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What Is A Photic Sneeze?

Sneezing is a common reaction that forces air through the nose and mouth. When the tissues of the nasal cavity are irritated, sneezing is an act that helps clear the cavity. This is a reaction that cannot be controlled and results in an explosive sound too.

Some people sneeze when they are suddenly exposed to a light source.

Reflexive sneezing that is induced by sunlight or other bright lights is called photic sneeze reflex.

Experts say that the photic sneeze reflex causes sneezing when people experience variations in the intensity of light.

Photic sneeze reflex is also called photosneezia or Autosomal Dominant Compelling Helio-Ophthalmic Outburst (ACHOO) syndrome.

About 10-35% of people in the world suffer from photic sneeze reflex.

White women seem to be at more risk for developing photic sneeze reflex. A study amongst 367 patients reported that 94.3% of photic sneezers were Caucasian (white) individuals and 67% of them were women. This study also mentioned that 90.7% of these individuals had three or lesser sneezes on sudden exposure to light. Only 12.3% of people had continuous reactions on exposure to light.

Symptoms of Photic Sneeze

The primary symptom of photic sneeze is sneezing when exposed to light. Most individuals don’t have extended reactions to light. They only react when they suddenly move from a dark space to a lit space. The number of sneezes ranges from 1-10.

How Does Genetics‌ Influence Photic Sneeze? ‌

ZEB2 Gene

The ZEB2 gene helps make a protein that plays a role in forming the nerve cells before birth. This protein is also important in making vital parts of the body like the kidneys and skeletal muscles.

rs10427255
The rs10427255 SNP is located near the ZEB2 gene. The minor C allele is the risk allele of this SNP and is associated with an increased risk for developing photic sneeze reflex.

Non-Genetic‌ ‌Influence‌s on Photic Sneeze

Deviated nasal septum - The nasal septum is the thin wall that gives structure to your nose. Some people’s nasal wall gets displaced or moves from the original place because of certain injuries. The risk for developing photic sneeze is high in people with a deviated nasal septum.

Use of tobacco - A certain study relates the use of tobacco with light-induced episodes of sneezing.

Optic nerve response - Some scientists believe that when the optic nerve is exposed to sudden light sources, it creates similar reactions in the body, like when the nose is irritated. This can cause episodes of sneezing.

Eye injections - In some cases, people end up having photic sneezing when they are given eye injections. These injections trigger the trigeminal nerve. This is one of the cranial nerves that give sensations to the various parts of the face. Triggering the nerve causes sneezing.

Prominent corneal nerves - According to a small study conducted, 67% of people with some degree of prominent corneal nerves experienced photic sneezing.

The Pesky Effects Of Photic Sneeze

Recommendations‌ ‌To‌ Manage Photic Sneeze

Cover your eyes - When you are stepping out in the sun, wear sunglasses to prevent direct exposure to sunlight. This is a very easy trick to prevent the flaring up of sneezes. You can also wear hats and scarves to bring down the intensity of sunlight.

Philtral Pressure Technique (PPT) - When you apply pressure to the sub-philtral region, it is said to help stop sneezing. The philtrum is the region between the nose and the upper lips. When you press this region gently with the index finger, this brings down the urge to sneeze.
When you press the philtrum region, this stimulates the mechanoreceptors. These receptors send signals to the brain when stimulated by an external medium (touch, in this case). These mechanoreceptor signals override the signals caused by trigeminal nerve stimulation and hence prevent sneezing.

Antihistamine sprays and drugs - Even though photic sneeze is not an allergic reaction, it seems to get better with antihistamine sprays and drugs.

Summary‌ ‌ ‌

  1. Photic sneeze reflex is a condition that causes people to sneeze when they are exposed to sudden light sources. Sunlight, flashlights, and other sources of lights that fall on a person suddenly can cause photic sneezing reflex. This reflex results in sneezing when the person is exposed to varying intensities of light.
  2. Photic sneeze reflex is also called Autosomal Dominant Compelling Helio-Ophthalmic Outburst (ACHOO) syndrome or photosneezia.
  3. A majority of people (about 90%) experience 1-10 sneezes when they come in contact with sudden light. They become alright after that. For some people, the reflex reaction can be prolonged and continuous.
  4. The C allele of the rs10427255 SNP located near the ZEB2 gene increases a person’s risk for developing photic sneeze.
  5. Some experts mention that triggers to the optic nerve results in an ‘allergy-like’ reaction in the body, causing sneezing.
  6. Protecting the eyes with sunglasses while stepping out and using antihistamine sprays and drugs can help manage photic sneeze reflex.

References‌ ‌

https://www.bbc.com/future/article/20150623-why-looking-at-the-light-makes-us-sneeze
https://pubmed.ncbi.nlm.nih.gov/7673597/
https://www.healthline.com/health/photic-sneeze-reflex#risks
https://www.nature.com/articles/s41433-019-0368-4
https://www.nature.com/articles/s41598-019-41551-0
https://www.pbs.org/newshour/science/does-the-sun-make-you-sneeze
https://medlineplus.gov/genetics/gene/zeb2/
https://www.snpedia.com/index.php/Rs10427255

One look at a cockroach walking on your kitchen floor or slab, and you rush to get it right out of your home! Cockroaches are icky pests that are known to spread germs and cause diseases. But, did you know, just like other animals, birds, and pollen, people can be allergic to cockroaches too?

You will be shocked to know that around 78%-98% of homes in urban areas contain cockroaches, and about 60% of the people with asthma who live in cities are allergic to cockroaches. A protein found in cockroaches triggers an allergic reaction in some people.

Like any allergy, cockroach allergy gets triggered by an allergen, often an enzyme (a type of protein) released from the body of roaches. This allergen is found in the cockroach’s saliva, waste, and body parts and spreads everywhere the cockroach goes. Coming in contact with these cockroach proteins can trigger an allergic reaction.

Symptoms of Cockroach Allergy

In people who are allergic to cockroaches, common symptoms include:
- Uncontrolled sneezing
- Runny or stuffy nose
- Itchy, red, and watery eyes
- Itchiness in throat, mouth, and nose
- Cough
- Skin itch and skin rash

In asthmatics, symptoms of cockroach allergy include:
- Wheezing
- Chest tightness
- Breathing trouble
- Whistling sound while breathing out

Cockroach Allergy and Asthma

Cockroach allergy has been reported as an important cause of asthma for over 50 years. Many studies that have been conducted so far establish a positive correlation between cockroach allergy and the development of asthma. The main reason for this is environmental exposure and sensitization to the various species of cockroaches that exist in the world today. In fact, this sensitization to cockroach allergens is the biggest risk factor for the development of asthma in low-income populations in urban setups.

How Does Genetics Contribute To Cockroach Allergy?

There are many genes and polymorphisms that have strong associations with this condition, particularly the genetic variants in TSLP, MBL2, CD14, and IL-12A genes.

IL-12A Gene

One particular gene, the IL-12A or Interleukin 12, and its variants influence cockroach allergy in children with asthma. IL-12A is involved in immune responses, especially the one involving T cells. IL-12A also has a role to play in the pathogenesis of asthma. The gene is located on the p-arm of chromosome 3.

Variations in The IL-12A Gene
Two SNPs, rs2243123 and rs2243151, associated with the IL-12A gene, have shown a risk of increased allergic susceptibility to different species of cockroaches

The presence of the T allele in SNP rs2243123 is associated with an increased risk of cockroach allergy with respect to the two common cockroach species P. Americana and B. germanica.

The presence of the A allele in SNP rs2243151 is associated with an increased risk of cockroach allergy.

Non-Genetic Influences on Cockroach Allergy

From the many studies performed on cockroach allergy and its association with asthma, non-genetic risk factors that increase one’s risk of developing the cockroach allergy include:

Recommendations for Managing Cockroach Allergy

Lifestyle modifications:
Individuals who are allergic to cockroaches need to make a few lifestyle modifications to avoid cockroaches as much as they can. Here’s what you can do:
- Always cover all your trash/garbage bins.
- Keep food, both cooked and uncooked, in airtight containers with proper lids.
- Clean up any food spills, crumbs, oil, etc., from the stovetop, counters, tables, and floor as these can attract cockroaches.
- Cockroaches like damp places. So, look out for any leaking pipes in your home and seal any cracks in the floor or walls from where cockroaches can enter the house.
- Use anti-cockroach sprays, gels, and traps to drive out or kill existing cockroaches from your house.

Cockroaches are common members in most homes, and an allergy to them is a very common occurrence too. If you suspect you have a cockroach allergy, or your symptoms seem to be getting worse, visit your doctor immediately to help bring it under control. A simple blood test or skin test can help diagnose if you or your loved one is allergic to cockroaches.

Summary

  1. Cockroaches are common members in most homes, so are cockroach allergies. It is rather surprising to know that a pest that is found in homes all over the world can trigger an allergy.
  2. The condition shows common allergic symptoms, and has a strong genetic component, and affects some races more than others.
  3. Variations in the IL-12 gene, associated with immune system responses, have been associated with an increased risk for cockroach allergies.
  4. A few lifestyle modifications, maintaining cleanliness and hygiene around the house can help prevent an allergic reaction. If you suspect you have a cockroach allergy, or your symptoms seem to be getting worse, visit your doctor immediately to help bring them under control. A simple blood test or skin test can help diagnose if you or your loved one is allergic to cockroaches.

References

https://www.aafa.org/cockroach-allergy/https://acaai.org/allergies/types/cockroach-allergy
https://pubmed.ncbi.nlm.nih.gov/8648037/
https://www.jacionline.org/article/S0091-6749(96)70209-9/fulltext
https://www.healthline.com/health/cockroach-allergy#bottom-line
https://www.webmd.com/allergies/nasal-allergy-trigger-cockroaches
https://www.nationaljewish.org/conditions/allergy/overview/allergens/cockroach
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2525650/

House Dust Mites or dust mites belong to the spider family and are small and microscopic beings present everywhere. They are 1/3rd of a millimeter in size and look like a small white bug.

Did you know that dust mites are present all over the world except in Antarctica? If you seem to have allergic reactions all through the year, then it could mean that you are allergic to dust mites.

Dust mites love humid and slightly warm temperatures and have strong survival skills. While there are up to 13 types of dust mites present, the three common types that could be present in your house are:
1. American house dust mites
2. European house dust mites
3. Mayne’s house dust mites

House mites feed on the dead skin flakes of humans and other animals. Since human beings shed 30,000-40,000 dead skin cells every minute, there is always so much food for dust mites to eat, flourish, and reproduce.

About 100,000 dust mites live in each square yard of your home carpet. The mattresses you sleep in have hundreds of thousands of dust mites happily living and reproducing.

If your pillow is 2+ years old, up to 10% of the weight of your pillow could be from dust mites and their droppings!

What is a Dust Mite Allergy?

People are usually not allergic to live dust mites. However, they react negatively to the droppings of these mites and the dead bodies of these mites. Every dust mite leaves behind at least 20 droppings a day. Imagine your mattress having 500,000 dust mites. That means every day, your mattress is filled with 10,000,000 new mite droppings!

Each dust mite can live for about 2-3 months. Female dust mites lay 60-100 eggs during their lifespan. As a result, the number of dust mites in your house multiplies every day.

This is the reason people’s allergic reactions to dust mites increase with time.

Symptoms of Dust Mite Allergy

If you are allergic to the dead mites and droppings of dust mites, then you can have the below allergic reactions.
- Sneezing
- Watery eyes
- Red and itchy eyes and nose
- Postnasal drip (dripping flow of mucus from the nose to your throat)
- Itchy and red skin
- Coughing and wheezing
- Shortness of breath

How Does Genetics Contribute To Dust Mite Allergy?

IL10 Gene

The IL10 gene produces the interleukin 10 protein. This protein plays a role in bringing down inflammation in the body. This is considered a good gene and brings down the unwanted effects of immune responses.

[The GG genotype of the rs3024496 SNP of this gene brings down the activity of the interleukin 10 protein and hence increases the risk of asthma when exposed to dust mites] (https://www.jacionline.org/article/S0091-6749(08)00599-X/fulltext).

rs117902240
The AC genotype of the rs117902240 SNP decreases FEV1 capacity and increases the risk of asthma attacks when exposed to excessive dust mites. FEV1 is a measure of a person’s vital capacity.

rs115997623
The minor T allele of the rs115997623 SNP is considered risky and is associated with reduced FEV1 function and an increased risk for asthma attacks with exposure to dust mites.

Non-genetic Influences On Dust Mite Allergy

Industrial settings: People who live in highly industrialized areas are exposed to more dust pollution and dust mites. These individuals have a higher chance of developing dust mite allergy.

Heredity: Though rare, dust mite allergy can run in the family. If your grandparents or parents have had dust mite allergies, the chances are that you develop it too.

Age: Infants and children are at higher risk for developing dust mite allergies than adults.

Exposure to excessive dust mites early in life: If a person has been exposed to excessive dust mites very early in life, he/she is at more risk for developing a dust mite allergy.

Smoking: Cigarette smoking can damage the airway epithelial cells. The airway epithelium is a column-like structure in the respiratory tract that prevents allergens and external elements from entering the tract. Tobacco smoke kills these cells and makes you vulnerable to dust mites. [Smoking also worsens symptoms of dust mite allergies] (https://pubmed.ncbi.nlm.nih.gov/10340943/).

Asthma and other allergies: 75% of children and 50% of adults with asthma are also diagnosed with other forms of allergies. Up to 85% of people with asthma and other allergies end up being allergic to house mites. This relationship between these different kinds of allergies makes it difficult to treat the underlying condition.

Managing Dust Mite Allergy

Confirm dust mite allergy
There are so many substances that can cause allergies and it is important to understand if you are allergic to dust mites. Here are some tests/diagnostic methods that help with the confirmation:
- IgE blood test - This blood test looks for IgE antibodies in the blood to identify if the person is having an adverse reaction to dust mites.
- Skin prick test - Exposes the skin to a small amount of dust mite allergen and checks the reactions.
- Atopic patch tests - Atopic patch tests make use of delayed reactions and the presence of T cells in the body to diagnose dust mite allergies.
- Basophil activation tests - Basophils are types of White Blood Cells that fight against external allergens. These tests look for basophil activation markers to know if a person is having an allergic reaction to dust mites.

Cover mattresses and pillows with thicker fabrics and plastic sheets
By covering mattresses with plastic sheets in the morning, you can prevent the penetration of dust mites into the mattress surface. Thicker and finely woven fabric covers in the night prevent dust mites from penetrating from the mattress to your body.

Don’t use carpets unless necessary
If not needed, carpets can be removed from floors, as this helps bring down dust mite growth at home.

Wash bedding in hot water
Make sure you wash your bedding at least once a week in hot water to kill dust mites. Drying the bedding in bright sunlight also helps kill existing mites.

Use air filters
Air filters or air purifiers come with HEPA (high-efficiency particulate air) filtration system and can eliminate microscopic dust mites and their particles from the room.

Use dehumidifiers
Dehumidifiers are appliances that help bring down the humidity levels in a room. If you live in a humid area, using these can help bring down the growth of dust mites.

Acaricide cleaners
Acaricides are kinds of pesticides used in killing dust mites and ticks. These are toxic in nature and need to be used with caution. Most people take the help of professional cleaners who use acaricide based products to get rid of mites.

Antihistamine sprays and drugs
Since dust mites cause general allergic reactions in the body, treating the reactions with antihistamine sprays and over the counter drugs help.

House dust mites allergen immunotherapy
This immunotherapy practice is also called desensitization. This involves injecting minute doses of the allergen (dust mites in this case) to the individual over a period of time to decrease sensitivity.
The injections are offered in regular periods for around 24 weeks, and this will be followed by 3-5 years of monthly maintenance schedules. This process gives permanent relief and reduces the flaring up of dust mite allergic symptoms.

Summary

  1. Dust mites are microscopic bugs that belong to the spider family. Hundreds of thousands of dust mites are present on all surfaces around you.
  2. Dust mites survive in humid and warm temperatures. The dead bodies and droppings of dust mites cause allergic reactions in human beings.
  3. The symptoms of dust mite allergy include watery eyes and nose, redness in eyes and nose, sneezing and coughing, and shortness of breath.
  4. Variations in the IL10 gene increase a person’s risk of developing asthma attacks because of dust mites. Few other SNPs also decrease FEV1 capacity and cause symptoms like shortness of breath and cough when the person is exposed to excessive dust mites.
  5. People living in industrial settings, habits like smoking, and asthma, and other allergies all result in an increased chance of dust mite allergy flare-ups.
  6. Washing bedding regularly in hot water, using air filters and dehumidifiers, and cleaning surfaces using acaricide products can all help handle house dust mites.

References

https://www.ncbi.nlm.nih.gov/books/NBK447098/
https://www.mayoclinic.org/diseases-conditions/dust-mites/symptoms-causes/syc-20352173
https://www.healthline.com/health/allergies/dust-mites#treatment
https://www.aafa.org/dust-mite-allergy/
https://acaai.org/allergies/types/dust-allergy
https://www.ehso.com/dustmites.php

What is Misophonia?

Misophonia means “hatred of sound” in Greek. Also called selective sound sensitivity syndrome, misophonia is the dislike or hatred of certain sounds to an extent where it interferes with daily lifestyle. It is a neurological condition that has both psychological and physiological symptoms.

Everyone gets occasionally irritated by certain sounds like chewing or clicking a pen. For people with misophonia, these sounds cause a severe reaction in them. They have very strong emotional reactions and physiological distress. The sensitivity to sound can cause a fight-or-flight response in people and interfere with their everyday lives. Emotional reactions like anxiety, rage, panic, anger, and hatred are triggered by this condition. This can also turn into verbal and physical aggression, avoidance, isolation, and depression.

The reaction is an involuntary physical and emotional reflex triggered by the sound. It activates the autonomic nervous system located in the brain and the limbic system associated with emotion. This results in emotional distress and the fight or flight response, which involves sweating, rapid heartbeat, and hormonal changes, among other symptoms. This reaction usually happens immediately within seconds of hearing the sound. The symptoms are instant and huge and take over cognitive functioning.

People with misophonia are often misdiagnosed as having anxiety or other disorders. This is because misophonia related research is fairly new. A lot of studies are being done to understand the condition better and establish more facts about it. It is not included in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which is the main resource for diagnosing mental disorders in the United States. There is an International Misophonia Network that lists doctors with knowledge of misophonia to help with the condition.

Triggers of Misophonia

The triggering sounds may vary over time and among different people. Almost any sound can be a potential trigger. The common triggers that cause misophonia are:
- Sounds related to the mouth like smacking lips, slurping, throat clearing, chomping, and swallowing
- Loud breathing sounds
- Clicking pens
- Papers rustling
- Clocks ticking
- Sounds of some animals
- Slamming car doors
- Certain visual triggers include wagging feet, twirling hair

Characteristics of Misophonia

Since misophonia-related research is fairly new, many health professionals cannot easily differentiate between it and other related conditions. A few characteristics of misophonia include:
1. More women have misophonia than men.
2. The symptoms are first seen between the ages of 9 to 12 in most people. The onset of this condition is generally before puberty.
3. The first reaction is usually triggered by a specific sound from a parent or other family members, and this intensifies over time, and new triggers arise.
4. People with this condition tend to have a higher IQ.

The Genetics Behind Misophonia

Misophonia is more common in women than in men. About 15-20% of adults with European ancestry were found to suffer from this condition. This indicates that there’s a genetic link to misophonia.

A genetic marker located near the TENM2 gene involved in brain development is associated with the feeling of rage at trigger sounds.

TENM2 Gene

The TENM2 gene encodes a protein called Teneurin-2. This protein is involved in neural development and neuronal connectivity.

rs1837253
rs1837253 is an SNP found in the TENM2 gene. The G allele of this SNP is the risk allele and is associated with an increased risk of the condition.

Non-Genetic Factors that Influence Misophonia

How to Manage Misophonia?

This is a lifelong disorder with no specific cure. However, the symptoms can be managed by following several measures.
- Try to actively avoid triggers as repeated exposure to the trigger can make the response worse.
- Maintaining good health, both emotional and physical, and help lessen the severity of the response for a trigger.
- Counseling: This can definitely help people manage their symptoms better and lead a normal lifestyle. Misophonia can have a negative impact on the people around you, too, as you display severe emotional and physical distress. Support is needed for both the person with the condition and their family. Misophonia Interantional, an advocacy and networking organization, provides a lot of useful information regarding this condition, including managing this condition and connecting with several researchers and trained professionals.
- Cognitive behavioral therapy: This may help change the negative associations linked to triggering noises. Audio of rain, nature, or other sounds are streamed using ear-level devices, and this helps most people experience a relief in symptoms.
- Treating tinnitus can help people tolerate triggering noises better.

Summary

  1. Misophonia is a condition where severe emotional and physical reactions are triggered by certain sounds. It is a neurological condition that has both psychological and physiological symptoms.
  2. Misophonia is often misdiagnosed, as research on this disease is fairly new. There is an international misophonia network that gives information about the condition and a list of professionals to consult.
  3. Sounds related to eating, breathing, movement of hands and feet are the common triggers of misophonia. Certain visual triggers can also induce symptoms.
  4. The genetic link to misophonia is the TENM2 gene. The G allele of SNP rs1837253 is found to increase the risk of misophonia.
  5. There is no definitive cure for this condition, but symptoms can be managed by avoiding triggers, maintaining a healthy and balanced lifestyle, counseling, and certain therapies.

References

https://www.healthline.com/health/misophonia
https://www.webmd.com/mental-health/what-is-misophonia#1
https://www.medicalnewstoday.com/articles/320682
https://misophoniainstitute.org/what-is-misophonia/
https://www.misophoniainternational.com/
https://www.snpedia.com/index.php/Rs2937573
https://www.23andme.com/topics/traits/misophonia/
https://rarediseases.info.nih.gov/diseases/12058/misophonia

What is Pet Allergy?

[In the United States, about 62% of households have pets] (https://www.aaaai.org/conditions-and-treatments/allergies/pet-allergy). At the same time, millions of Americans are allergic to pets.

The most common pet allergen is dander, the dead skin shed by pets. Other allergens include proteins found in the pet’s urine and saliva. The overreaction of the immune system results in an allergic reaction. The immune system recognizes the protein in the animal’s skin, saliva, or urine as foreign and produces histamine and other chemicals that lead to the symptoms of an allergy.

The pet allergens can even be found in homes that don’t have pets, as you can carry them on your clothing. The allergens can be found on furniture and walls. They spread through the air whenever the animal is petted or groomed, and can stay airborne for a long time.

Signs and symptoms are usually very mild and can be easily managed. The allergy can be life-threatening in rare cases where there is a severe allergic reaction like anaphylaxis. This impairs breathing and can send the body into shock if immediate action is not taken. Anaphylaxis can also lead to cardiac arrest.

Cats and dogs are the leading cause of pet allergies. Other animals like rodents and rabbits can also cause allergies. Animals without fur, rarely cause allergies.

Symptoms of Pet Allergy

The symptoms vary from person to person and can usually occur immediately after consumption or after a few hours. The symptoms are common to those seen in other allergic reactions.
- Runny or stuffy nose
- Nasal congestion causing pain
- Coughing
- Wheezing
- Hives
- Watery, red, or itchy eyes
- Anaphylaxis in severe cases
- Difficulty breathing
- Eczema
- Itchy skin

The Genetics Behind Pet Allergy

Variations in certain genes have been observed in people with pet allergies. Studying these variations can help predict if a person has a higher risk of getting the allergy compared to other people.

HLA-DQB1 Gene

The HLA-DQB1 gene is part of the family of genes that form the human leukocyte antigen (HLA) complex. The proteins produced by these genes play an important role in the immune system of the body. They help in distinguishing between self and foreign proteins and trigger the necessary immune response.

Variations in this gene are found to be associated with asthma and allergic rhinitis.

rs7775228
rs7775228 is an SNP found in the HLA-DBQ1 gene. People with the minor allele, the C allele, are found to have an increased risk of asthma, and [allergic rhinitis] (https://pubmed.ncbi.nlm.nih.gov/22036096/).
The C allele has also been associated with increased sensitivity to dog allergens.

LRRC32 Gene

The LRRC32 gene encodes for a membrane protein that contains 20 leucine-rich repeats. It regulates a key regulator of a growth factor called TGF-B, which is involved in several functions of the immune system.

rs2155219
rs2155219 is an SNP found in the LRRC32 gene. People with the minor allele, G allele are found to have a 1.18X increased risk of allergic sensitization. The TT genotype is found to be associated with allergic rhinitis.

If one or both the parents have any allergies or asthma, the child is more likely to develop a pet allergy.

Identifying Pet Allergy

Skin-prick test: A small amount of purified allergen extract is pricked into the skin on the forearm or back. After 15-20 minutes, if signs of allergy like redness or itching are observed, you’re found to be allergic to that specific allergen.

Blood test: Blood samples are tested for the presence of allergic antibodies against proteins found in pet dander, urine, or saliva. This can indicate how sensitive you are to an allergen.

How to manage pet allergy?

The best way to manage any allergy is to avoid the allergen causing it. This can prevent severe allergic reactions.

Lifestyle:
If you decide to give away your pet, you still need to thoroughly clean your house to get rid of all the allergens. Replace carpets, bedding, upholstered furniture, and vacuum your entire house with HEPA filters.

If you still want to keep your pet, there are certain measures you can take to avoid an allergic reaction.
1. Ask someone else you live with who does not have allergies to give frequent baths to your pet, at least once a week.
2. Make your bedroom a pet-free zone as you would spend most of your time there. This prevents allergens from settling on things in the room.
3. Use air purifiers with HEPA filters to remove allergens in the air. Vacuum your house frequently with machines containing HEPA filters.
4. Remove any furniture, upholstery, and curtains that can collect dander easily. Try to avoid carpets also.
5. Wear a dust mask if you cannot find anyone to help with cleaning your pet.
6. Clean the pet’s kennel, litter box frequently. It would be better if someone without allergies can help with this.

Studies show that being exposed to pets early in life can help avoid allergies.

Medications:
You may need to take allergy medications in addition to taking measures to avoid the allergen. Your doctor may prescribe any of the following medications based on your case:
- Antihistamines
- Decongestants
- Corticosteroids
- Leukotriene modifiers

Treatments:
1. Immunotherapy: This is done through a series of allergy shots. Small doses of allergen are given as weekly shots, and the dosage is gradually increased to get your immune system used to the allergen.
2. Nasal irrigation: A specially designed squeeze bottle or a neti pot can be used to flush the allergen and thickened mucus out of your sinuses. A prepared saline solution is used.

Summary

  1. Some people are allergic to pet dander, proteins present in the pet’s saliva or urine. This leads to symptoms of allergies. The immune system considers these proteins as foreign and mounts an immune response.
  2. The symptoms of pet allergy include wheezing, nasal congestion, watery, red, itchy eyes, difficulty breathing, to name a few.
  3. The C allele of rs7775228, an SNP found in the HLA-DBQ1 gene is associated with an increased risk of asthma and allergic rhinitis. The G allele of SNP rs2155219 found in the LRRC32 gene increases the risk of allergic sensitization. The T allele of the same SNP is associated with allergic rhinitis.
  4. If asthma or allergies run in your family, you are more likely to get pet allergies.
  5. A skin-prick test or blood test can be used to diagnose what you’re allergic to.
  6. Certain lifestyle changes, medications, and treatments can help avoid or manage symptoms of pet allergy.

References

https://www.niehs.nih.gov/health/topics/agents/allergens/pets/index.cfm
https://www.aafa.org/pet-dog-cat-allergies/
https://acaai.org/allergies/types/pet-allergy
https://www.mayoclinic.org/diseases-conditions/pet-allergy/symptoms-causes/syc-20352192
https://www.ncbi.nlm.nih.gov/pubmed/23817569
https://www.snpedia.com/index.php/Rs7775228
https://www.snpedia.com/index.php/Rs2155219

What is Contact Dermatitis?

Contact dermatitis is a reaction that occurs when you touch or come in contact with certain substances (typically an allergen or irritant). When your skin comes into contact with substances that you’re allergic or sensitive to, it can become red, itchy, and irritated. These substances include certain chemicals present in skincare products, detergents, jewelry made of certain metals, and poison ivy. Contact dermatitis usually presents as a rash on your skin in the affected area. The protective layer of your skin gets damaged, dry, cracked, and forms blisters. Most reactions aren’t severe and can be easily managed or treated completely.

Symptoms of Contact Dermatitis

The general symptoms include:
- Swelling
- Redness
- Skin irritation
- Bumps, blisters (rarely)
- Itching or burning
- Tender skin

The symptoms can vary based on the type of contact dermatitis. They can be mild or severe and can appear immediately on contact or a few days later. Contact dermatitis is not contagious. The hands are known to be the most common part affected by contact dermatitis.

Types of Contact Dermatitis

  1. Allergic contact dermatitis - An allergic reaction develops on contact with allergens like poison oak or poison ivy, latex, jewelry made of certain metals, and chemicals in cosmetic products.
  2. Irritant contact dermatitis - This is the most common type of contact dermatitis, that occurs when the skin comes into contact with toxic substances like bleach, detergents, or battery chemicals. People whose hands are frequently exposed to water or soap also experience irritant contact dermatitis.
  3. Phytophotodermatitis - This is the least common type of contact dermatitis, that occurs when your skin comes in contact with certain plant chemicals. These chemicals on exposure to sunlight get activated and cause skin reactions.

The Genetics Behind Contact Dermatitis

Variations in certain genes are found to increase a person’s risk of contact dermatitis. The risk for contact dermatitis runs in families. It can be passed down through generations. Research is still being done to establish further relations between genetics and contact dermatitis.

FLG Gene

FLG gene codes for a protein called filaggrin. Filaggrin is involved in the formation of the outermost layer of skin. It acts as a binder between other proteins present in the skin layer. It maintains a skin barrier against allergens, irritants, bacteria, and viruses. It also helps the skin remain hydrated.

Variants in this gene can decrease the production of the protein, compromising the structure of the outermost layer of skin allowing allergens to enter. This increases the risk of skin allergies and other skin disorders.

rs61816761
rs61816761 is an SNP found in the FLG gene. The A allele results in decreased production of filaggrin and increases the risk of skin allergies and other skin related disorders. The G allele is not associated with any skin related problems.

TNF Gene

TheTNF gene encodes the Tumor Necrosis Factor, which is a proinflammatory cytokine found in immune cells. This is mainly involved in the chronic inflammation process in the body. This gene has been implicated in various conditions like asthma, heart disease, liver disease.
Repeated exposure to allergens leads to inflammation on the skin. This is called the elicitation phase. TNF plays an important role in this phase of allergic contact dermatitis.

rs1800629
rs1800629 is an SNP found in the TNF gene. The A allele leads to increased production of TNF and a higher risk of developing allergic contact dermatitis compared to the G allele, which is the major allele.

Non-genetic Factors That Influence Contact Dermatitis

How to Manage Contact Dermatitis?

Home Remedies

Finding Potential Triggers

If you have sensitive skin, do a patch test or spot test before using any new product. A patch containing the product or the product itself is applied on a spot in the forearm and covered. Avoid using water or soap near the spot for 48 - 96 hours. If there’s any reaction like redness or itching, the product contains a potential allergen or irritant and should be avoided.

In Cases Of Severe Reaction

Summary

  1. Contact dermatitis is a reaction on the skin that causes redness, itching, irritation on contact with certain substances. These substances include certain chemicals, poison ivy, metals, detergents, and cosmetic products.
  2. The symptoms include rashes, itching, irritated skin, blisters, and dryness. The types of contact dermatitis include allergic, irritant, and phytophotodermatitis.
  3. Genes play a role in increasing your risk of contact dermatitis. The A allele of rs61816761, an SNP found in the FLG gene, increases the risk of contact dermatitis and other skin allergies. The A allele of rs1800629, an SNP found in the TNF gene, also increases your risk of allergic contact dermatitis.
  4. People who work in the construction industry, beauty industry, and healthcare industry increase their exposure to allergens and irritants.
  5. Contact dermatitis can be managed by finding the trigger and avoiding further contact. Certain home remedies can help treat the condition fully. In severe cases, a healthcare professional should be consulted.

References

https://www.healthline.com/health/contact-dermatitis#symptoms
https://www.webmd.com/skin-problems-and-treatments/contact-dermatitis#2
https://www.ncbi.nlm.nih.gov/pubmed/28300283
https://www.verywellhealth.com/contact-dermatitis-causes-83205
https://www.snpedia.com/index.php/Rs1800629
https://pubmed.ncbi.nlm.nih.gov/18620134/
https://www.ncbi.nlm.nih.gov/gene/2312
https://pubmed.ncbi.nlm.nih.gov/23374260/
https://www.snpedia.com/index.php/Rs61816761
https://onlinelibrary.wiley.com/doi/abs/10.1111/cod.12362

What is Egg Allergy?

Egg allergy is a reaction of the body’s immune system against eggs. Proteins present in the egg white are more likely to cause an allergy than the proteins present in the yolk. Some people can be allergic to both.

The overreaction of the immune system results in an allergic reaction. The immune system recognizes the protein in egg white/yolk as foreign and produces histamine and other chemicals that lead to the symptoms of an allergy.

Egg allergy is very common in children. Most children usually grow out of it before adolescence. In the US, about 2 percent of the total children population are known to be allergic to eggs. Egg allergies usually occur during infancy and become severe between 6 and 15 months of age. There are cases of egg allergy reported in adults also.

Signs and symptoms are usually very mild and can be easily managed. The allergy can be life-threatening in rare cases where there is a severe allergic reaction like anaphylaxis. This impairs breathing and can send the body into shock if immediate action is not taken.

If you’re allergic to eggs, you may be at an increased risk of other food allergies like milk or peanut allergy, allergies to pet dander, pollen, or dust mites, atopic dermatitis, and asthma.

Symptoms of Egg Allergy

The symptoms vary from person to person and can usually occur immediately after consumption or after a few hours. The symptoms are common to those seen in other allergic reactions.
- Skin inflammation, swelling, hives
- Redness of face
- Nasal congestion
- Stomach pain, vomiting, diarrhea
- Signs and symptoms of asthma-like wheezing, cough, shortness of breath
- Pale or blue skin
- Sneezing
- Dizziness
- Anaphylaxis in severe cases
- Lip or eyelid swelling, itchy ear, nose, or throat (usually in adults)

The Genetics Behind Egg Allergy

Variations in certain genes have been observed in people with egg allergies. Studying these variations can help predict if a person has a higher risk of getting the allergy compared to other people.

ABCB11 Gene

The ABCB11 gene encodes a protein in the liver called bile salt export pump. Bile salts present in bile released by the liver are transported through this pump. This is an indication of healthy liver function. Variation in this gene is found to be associated with egg allergy.

rs16823014
rs16823014 is an SNP found in the ABCB11 gene. The minor allele, A allele, is found to increase one’s risk of developing egg allergy.

ERCC4 Gene

The ERCC4 gene encodes the ERCC4 protein, which is a DNA repair endonuclease. It is known to participate in DNA repair and recombination along with other proteins. Variation in this gene is found to be associated with egg allergy.

rs6498482
rs6498482 is an SNP found in the ERCC4 gene. The minor allele, the C allele, is associated with an increased risk of egg allergy in individuals.

If one or both the parents have any food allergy or other allergic diseases like asthma, hives, or eczema, the child has an increased risk of egg allergy.

Non-Genetic Factors that Influence Egg Allergy

Age: Children are more prone to having an egg allergy. Allergic reactions are less likely to occur in older people.

Atopic dermatitis: Children who have this skin problem are more likely to develop a food allergy.

Diagnosing Egg Allergy

Skin-prick test: A small amount of liquid containing egg protein is allowed to seep into the skin on the back or forearm by piercing. After 15-20 minutes, if signs of allergy like redness are observed, the person is said to be allergic to eggs. You can determine which protein of egg you’re allergic to using this test.

Blood test: Blood samples are tested for the presence of allergic antibodies against egg proteins.

Oral food challenge: Small amounts of eggs are consumed under the supervision of an allergist or trained staff to see if any reaction occurs.

Food elimination diet: If the symptoms disappear on eliminating eggs from your daily diet, you may be allergic to eggs.

Managing Egg Allergy

The best way to manage any allergy is to avoid the allergen causing it. This can prevent severe allergic reactions.

Food products: Start reading the labels on food products. Most foods that include the words emulsifier, binder, coagulant, or any other ingredients that begin with ova contain eggs and should be avoided.
Various food items like mayonnaise, baked goods, frostings, and processed meat contain eggs. Be sure to read the ingredients carefully and find out if any form of egg is present in the item to avoid an allergic reaction. Make a list of all the products that contain eggs or related proteins and avoid them.

Egg replacers: Several egg replacers are available in the market. These include applesauce, yogurt, vinegar, baking soda, mashed banana, and ground flax or chia seeds. These can be used instead of eggs while baking. There are various other protein sources that you can include in your diet instead of eggs.

Allergy bracelet or necklace: Children should wear an allergy bracelet or necklace that informs people of the allergy, especially if the child can develop a serious reaction to eggs.

Vaccines that contain egg proteins: There are a few vaccines that contain egg proteins. Examples include the flu vaccine, yellow fever vaccine, and MMR vaccine. Inform the healthcare professional about your allergy before they prescribe any vaccination or medication to you.

Severe allergic reactions: Epinephrine in an auto-injector is usually used to treat anaphylaxis, which is a severe allergic reaction. This should be carried with a person susceptible to severe allergic reactions and used when symptoms start to occur.

Summary

  1. Egg allergy is a reaction of the body’s immune system against the protein present in eggs. They are treated as a foreign substance and attacked by the immune system. Egg allergy is more common in children than in adults. Most children outgrow their symptoms as they grow old except in certain cases.
  2. The symptoms of egg allergy are common to other allergies. They include redness, inflammation, stomach pain, and shortness of breath.
  3. Variations in certain genes are found to increase the risk of egg allergy. The A allele of rs16823014, an SNP found in the ABCB11 gene, and the C allele of rs6498482, an SNP found in the ERCC4 gene, are known to increase your risk for egg allergy.
  4. There are a few tests that can be done to find out if the egg proteins are a trigger for your allergic reactions.
  5. The best way to prevent symptoms is to avoid the consumption of eggs. Make sure you know the ingredients present in the food you’re eating. Several egg replacers are available to use in baking.

References

https://acaai.org/allergies/types-allergies/food-allergy/types-food-allergy/egg-allergy
https://www.healthline.com/health/allergies/egg
https://www.ncbi.nlm.nih.gov/pubmed/25710614
https://www.mayoclinic.org/diseases-conditions/egg-allergy/symptoms-causes/syc-20372115
https://www.healthline.com/nutrition/egg-substitutes
https://medlineplus.gov/genetics/gene/abcb11/
https://www.genecards.org/cgi-bin/carddisp.pl?gene=ERCC4

What is Milk Allergy?

Milk allergy is a reaction of the body’s immune system against milk and milk products. It is most often caused by the alpha S1-casein protein present in cow’s milk. Milk from sheep, goats, buffalo, and other mammals can also cause an allergic reaction in some people.

The overreaction of the immune system results in an allergic reaction. The immune system recognizes the protein in milk as foreign and produces histamine and other chemicals that lead to the symptoms of an allergy.

Milk allergy is the most common food allergy in children. Milk is one of the 8 types of food that cause 90% of allergies in children. Most children outgrow the allergy before adolescence.

Milk allergy is usually confused with lactose intolerance because of common symptoms. They’re not the same condition. Lactose intolerance is caused by the absence of an enzyme called lactase, needed to metabolize a milk sugar called lactose. Milk allergy is an allergic reaction to a protein present in milk.

Some people are allergic to almond milk or soy milk as well, which are commonly used as alternatives to cow’s milk. The right trigger of the reaction should be identified to manage the allergy.

Signs and symptoms are usually very mild and can be easily managed. The allergy can be life-threatening in rare cases where there is a severe allergic reaction like anaphylaxis. This impairs breathing and can send the body into shock if immediate action is not taken. Anaphylaxis can also lead to cardiac arrest.

If you’re allergic to milk, you may be at an increased risk of other food allergies like eggs, peanut or beef allergy, allergies to pet dander, pollen, or dust mites, which causes hay fever.

Symptoms of Milk Allergy

The symptoms vary from person to person and can usually occur immediately after consumption or after a few hours. The symptoms are common to those seen in other allergic reactions.
- Skin rash
- Diarrhea
- Wheezing
- Vomiting
- Hives
- Cough, sinus infection
- Swelling of lips and tongue
- Itching of lips and mouth
- Watery eyes
- Colic in babies
- Anaphylaxis in severe cases

The Genetics Behind Milk Allergy

Variations in certain genes have been observed in people with milk allergies. Studying these variations can help predict if a person has a higher risk of getting the allergy compared to other people.

IL2 Gene

The IL2 gene encodes a cytokine called interleukin 2, which is part of immune signaling in the body. It is involved in regulating white blood cells and is also a part of the body’s immune response against foreign bodies like microbes. Mutations in this gene have been found to be associated with milk allergy.

rs2069772
rs2069772 is an SNP found in the IL2 gene. The T allele is found in people who are allergic to cow’s milk.

TLR6 Gene

The TLR6 gene encodes a protein called toll-like receptor 6. This protein plays a major role in innate immunity, which is the first non-specific defense by the immune system against a foreign body. TLR6 is also involved in recognition of pathogens like bacteria and fungi. They trigger the immune system to produce chemicals necessary to fight the pathogens. Mutations in this gene have been found to be associated with milk allergy.

rs17616434
rs17616434 is an SNP found in the TLR6 gene. The C allele is found in people who are allergic to cow’s milk.

Non-Genetic Factors that Influence Milk Allergy

Age: Children are more prone to milk allergy. Allergic reactions are less likely to occur in older people.

Atopic dermatitis: Children who have this skin problem are more likely to develop a food allergy.

Pre-existing conditions: Any food allergy or other allergic diseases like asthma, hives, or eczema increases the risk of milk allergy.

Non-Genetic Factors that Influence Milk Allergy

Age: Children are more prone to milk allergy. Allergic reactions are less likely to occur in older people.

Atopic dermatitis: Children who have this skin problem are more likely to develop a food allergy.

Pre-existing conditions: Any food allergy or other allergic diseases like asthma, hives, or eczema increases the risk of milk allergy.

Diagnosing Milk Allergy

Skin-prick test: A small amount of liquid containing milk protein or milk protein extract is allowed to seep into the skin on the back or forearm by piercing. After 15-20 minutes, if signs of allergy like redness, raised welt are observed, the person is said to be allergic to milk.

Blood test: Blood sample is tested for the presence of allergic antibodies against milk protein. A newer type of blood test called component test is used to look for severe allergic reactions to specific proteins in milk.

Oral food challenge: Small amount of milk or milk powder is consumed under the supervision of an allergist or trained staff to see if any reaction occurs.

Managing Milk Allergy

The best way to manage any allergy is to avoid the allergen causing it. This can prevent severe allergic reactions.

Food products: Start reading the labels on food products. Look for casein, a milk derivative that is also found in tuna, sausages, and other non-dairy products. The other main milk protein to look out for is whey.
Several food items are marked as milk-free or non-dairy but can contain certain milk proteins or derivatives that can lead to allergies.
Make a list of all the products that contain milk or related proteins and avoid them.

Milk alternatives: For cooking or baking, milk can be easily substituted with water, juice, or other types of milk like soy or rice milk. Soy or rice milk can also cause an allergic reaction in some people.
If an infant is allergic to milk, the doctor would recommend hypoallergenic formulas that contain milk proteins broken down by enzymes. Depending on the level of breakdown, they are classified as partially, extensively hydrolyzed, or elemental formula. Amino acid-based formulas are also available. Talk to a doctor about what alternative would be best for your infant.

Allergy bracelet or necklace: Children should wear an allergy bracelet or necklace that informs people of the allergy, especially if the child can develop a serious reaction to milk.

Severe allergic reactions: Epinephrine in an auto-injector is usually used to treat anaphylaxis, which is a severe allergic reaction. This should be carried with a person susceptible to severe allergic reactions and used when symptoms start to occur.

Summary

  1. Milk allergy is a reaction of the body’s immune system against the protein present in milk. They are treated as a foreign substance and attacked by the immune system. Most children outgrow their symptoms as they grow old except in certain cases. Casein and whey are two milk proteins that are common causes of milk allergy in children.
  2. The symptoms of egg allergy are common to other allergies. Few symptoms are redness, wheezing, hives, and shortness of breath.
  3. Variations in certain genes are found to increase the risk of milk allergy. The T allele of rs2069772, an SNP found in the IL2 gene, and the C allele of rs17616434, an SNP found in the TLR6 gene, are known to increase your risk for milk allergy.
  4. There are a few tests that can be done to find out if the milk proteins are a trigger for your allergic reactions.
  5. The best way to prevent symptoms is to avoid the consumption of milk and related products. Make sure you know the ingredients present in the food you’re eating. Substitutes can be used in cooking, and hypoallergenic formulas can be used for infants.

References

https://www.healthline.com/health/allergies/milk
https://acaai.org/allergies/types-allergies/food-allergy/types-food-allergy/milk-dairy-allergy
https://www.mayoclinic.org/diseases-conditions/milk-allergy/symptoms-causes/syc-20375101
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776421/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4340086/
https://www.genecards.org/cgi-bin/carddisp.pl?gene=IL2
https://www.genecards.org/cgi-bin/carddisp.pl?gene=TLR6

What is Nut Allergy?

Nuts are types of fruits that come covered in an inedible and hard shell with an edible seed inside. Nuts are a popular source of food as they are energy-dense and calorie-rich. Starting from small pine nuts to larger walnuts, macadamia nuts, and hazelnuts, there are so many tree nuts enjoyed all over the world.

This is a serious condition that affects almost 3 million Americans and 1.1% of the general population.

Nut allergy lasts for a lifetime and can lead to serious complications when the affected person is not treated. 80% of all children diagnosed with tree nut allergies don’t outgrow the condition.

What Causes Allergic Responses In People With A Nut Allergy?

When a person with a nut allergy consumes nuts, the person’s body considers it as a harmful and dangerous foreign substance. The immune system is alerted, and it releases a hormone called histamine to handle the foreign substance.

Histamine can cause a variety of responses in the body, some of which can be unpleasant and painful.

Nut Allergy Symptoms

Are Peanut Allergy And Nut Allergy The Same?

Most people assume that peanuts are a form of nuts. This is not true. Peanuts are legumes, and a peanut allergy is different from a nut allergy. However, if you are allergic to peanuts, it is common to be allergic to one or a few types of nuts too.

Also, if you are allergic to one nut, you could be allergic to others too. This is why doctors advise people with a diagnosed nut allergy to stay away from all kinds of nuts.

How Does Genetics Influence Nut Allergy?

STAT6 Gene

The STAT6 gene helps produce the Signal Transducer And Activator Of Transcription 6 protein. This protein controls the IL4-mediates inflammatory biological responses in the body. IL-4 promotes conditions like asthma and allergic inflammations in the body.

rs324015 polymorphism in the STAT6 gene
A nut allergy study carried out in the UK, compared the effects of the rs324015 polymorphism of the STAT6 gene on nut allergies. The study concluded that those with nut allergies had an increased frequency of the G allele of the rs324015 SNP.

Non-Genetic Influences On Nut Allergies

Age - Tree nut allergies are more common in children and toddlers when compared to adults. The symptoms are also more severe in children whose digestive systems are not as mature as that of adults.

Other related allergies - If you have some kind of food allergy or an existing case of peanut allergy, it is expected that you also develop a nut allergy.

Cross-contamination - Cross-contamination is a process by which nuts allergic to you get transferred to another safer food substance unintentionally. Such contaminations can happen during the production or packaging process. If you have existing nut allergies, cross-contamination can end up causing a flare-up of the symptoms.

This is why the FALCPA (Food Allergen Labeling and Consumer Protection Act of 2004) requires food and beverage brands to mention if their manufacturing facility deals with nuts, even if nuts are not added as an ingredient.

Atopic dermatitis - About 20-40% of children with atopic dermatitis end up having some kind of food allergy, including peanut and tree nut allergies. If your child is diagnosed with atopic dermatitis, make sure you introduce nuts with caution.

Recommendations To Prevent Nut Allergy Flare-Ups

Avoid nuts - One of the most simple solutions to prevent nut allergies from flaring up is to avoid eating nuts. If you find yourself allergic to one nut, it is recommended you stay away from all nuts to be on the safer side.

Check the labels - If you have a nut allergy, definitely check the label of the food/beverage you choose thoroughly before buying it. Brands are required to mention in bold fonts if their product contains nuts.

Take care when you choose alcoholic beverages - Some alcoholic beverages may use nuts in the distillation process. When you find an alcoholic beverage with ‘botanical’ or ‘natural’ additives in it, talk to the manufacturer to know whether nuts are a part of the distillation process.

Keep your medications close to you - People with nut allergies have to carry an auto-injector with them all the time to handle allergic attacks. Such individuals should also be on anti-histamine drugs to bring down the severity of their allergic reaction.

Nut-proof the house - It is safer to not bring anything with nuts inside the house. If you have guests coming over, telling them in advance about not bringing nut-based foods and beverages helps too.

Introduce nuts in your diet early on - Studies say that when you slowly introduce nuts to babies from 6 months of age, their tolerance to the same increases, and the chances of them developing an allergy is low. Start with very low amounts and introduce one nut at a time to watch for allergic reactions. Keep your pediatrician informed if you are planning to introduce nuts.

Summary

  1. Nut allergy is an allergic reaction in the body to consuming nuts. About 3 million Americans are diagnosed with nut allergies, and 1% of the global population is allergic to nuts.
  2. Nut allergies cause histamine production in the body and lead to symptoms like skin rashes, watery and puffed up eyes, swollen tongue and lips, and coughing and wheezing.
  3. Extreme cases of nut allergies cause anaphylaxis. This causes the body to go into shock and leads to breathlessness and constriction of airways.
  4. Polymorphisms in the STAT6 gene lead to an increased risk for nut allergies.
  5. Children are more prone to developing nut allergies than adults. Having other kinds of food allergies also make you risky for nut allergies.
  6. Checking food and beverage labels carefully before buying food, nut-proofing your house, and keeping your medications close to you all help bring down the risk of nut allergy flare-ups.

References

https://nationaleczema.org/atopic-dermatitis-and-allergies-connection/
https://acaai.org/allergies/anaphylaxis
https://patient.info/allergies-blood-immune/food-allergy-and-intolerance/nut-allergy#nav-2
https://www.healthline.com/health/allergies/nut-allergy-symptoms#check-your-food-labels
https://www.healthline.com/health/allergies/nut-allergy-symptoms#check-your-food-labels
https://www.medicalnewstoday.com/articles/327033#treatments
https://acaai.org/allergies/types/food-allergies/types-food-allergy/tree-nut-allergy

What is Peanut Allergy?

Peanut allergy is a type of food allergy that causes an immune reaction on exposure to peanuts. In some individuals, even the smallest amount of peanut exposure can result in a severe, life-threatening allergic reaction called anaphylaxis. 

About 1-2% of the population is allergic to peanuts. If you have a close relative with a peanut allergy, your risk of being allergic to peanuts is 7%. So you are 14 times more likely to have a peanut allergy if you have a relative with peanut allergy. Non-identical twins in a fraternal twin pair had peanut allergies 7% of the time. Identical twins on the other hand, had the allergies 64% of the time, which indicates a strong genetic component in this type of allergy.

There have been multiple studies on peanut allergy, and the most likely cause for it is said to be genetic. Peanut allergy occurs when an individual’s body wrongly identifies the harmless protein in peanuts as a harmful substance and launches an immune attack against it. The chemicals released by the body’s immune system against the peanut protein trigger a range of symptoms. The contact with peanuts can be direct, indirect, or by inhalation.

Symptoms of Peanut Allergy

The allergic reaction occurs just minutes after exposure to peanuts in any form. Signs and symptoms of the allergy include:

In some cases, peanut allergy can be life-threatening and a medical emergency. This type of reaction is called an anaphylactic reaction. Symptoms of an anaphylaxis reaction due to peanut allergy include:

Evolution and Allergies

Peanuts are rich in proteins and are unconventional because they flower over the ground, whereas their pods containing seeds are present underground. This is why they are called a geocarpic fruit. Due to this nature of the peanut plant, the pods and seeds come in contact with many soil pathogens and pests, including the fungus Aspergillus. The seed proteins of peanuts are modified slightly when they come in contact with this fungus, in order to survive. These modified proteins in the peanut seed membranes trigger our body’s immune receptors and modulate the immune pathways to release IgE.

This evolutionary history can be explored further to understand how the humble peanut became one of “The big eight food allergens in the world”.

How Do Genes Influence Peanut Allergy?

HMGA2 Gene

The HMGA2 gene, or High Mobility Group AT-Hook 2, is responsible for encoding a protein that belongs to the non-histone chromosomal high mobility group family of proteins.

rs10878354 and peanut allergy

SNP rs10878354 is a G>A polymorphism located on chromosome 12 in the gene HMGA2 Gene. The presence of the G allele significantly increases the risk of developing peanut allergy.

ZFAT gene

Zinc Finger And AT-Hook Domain Containing or ZFAT gene encodes a protein that binds DNA and acts as a transcriptional regulator in the process of cell survival and cell death. It is also a susceptibility locus for autoimmune thyroid disease on chromosome 8.

rs4584173 and peanut allergy

rs4584173 is a T>C polymorphism that is located on chromosome 8. The presence of the T allele increases one’s chance of developing peanut allergy.

HLA-DRA Gene

Major Histocompatibility Complex, Class II, DR Alpha is a part of the HLA Class II alpha chain. This gene plays a prominent role in the immune system as it is entrusted with the responsibility to present peptides derived from extracellular proteins.

rs7192 and peanut allergy

rs7192 is one of the most strongly associated genetic polymorphisms with peanut allergy. Having one T allele increases one’s risk of developing peanut allergy by 1.7 times, whereas having two T (TT) alleles increases the risk by 3 times.

HLA-DQB1 Gene

The HLA-DQB1 gene is associated with asthma, a condition that is characterized by the release of IgE on exposure to trigger factors. The genes of the HLA family belong to the Major Histocompatibility Complex(MHC) locus, which are involved in antigen presentation to T cells.

It is also important to note that asthma and food allergies are linked.

rs9275596 and peanut allergy

rs9275596 is located between HLA-DQB1 and HLA-DQA2 on chromosome 6. Similar to SNP rs7192, rs9275596 is also associated with an increased risk of peanut allergy. Having a single C allele increases one’s risk of developing peanut allergy by 1.7 times, whereas having two ‘C’ alleles (CC) increases the risk by three times.

Non-Genetic Influences on Peanut Allergy

While genetics is claimed to be the main reason for peanut allergies, there are also other risk factors that have a significant effect:

- Allergies to other foods: If you are allergic to other food items, you are at an increased risk of peanut allergy too. It has also been observed that having hay fever increases one’s chances of developing peanut allergy.

How To Manage Peanut Allergy?

Dietary recommendations

- If you are allergic to peanuts, you must stay away from all foods that contain or are prepared using peanuts or its products like peanut oil.

- When you pick packaged foods, read the label carefully to check for other products that can trigger an allergic reaction similar to peanuts. These include monkey nuts, peanut butter, peanut flour, mixed nuts, and peanut oil, to name a few.

- You must also avoid cold-pressed, expelled, and expressed peanut oil, as these can trigger peanut allergy too.

- It is also recommended to avoid other nuts, nut butter, and extracts to be 100% sure you are staying safe.

Lifestyle modifications

If you are allergic to peanuts, there may be some chance that you are allergic to other nuts or foods too. To avoid an untoward allergic reaction, here are a few lifestyle modifications that can come in handy:

- Be cautious and never assume that a food does not contain allergens. This will prompt you to ask at a restaurant before you order a dish.

- Make it a habit to read food labels and warnings as relevant information is usually mentioned on it.

- It is okay to say ‘no’ to a dish that you are unsure of at a party or social gathering if you suspect peanuts or other possible allergens are present in it.

- If you or your child is allergic to peanuts, always carry emergency medications. It is always better to be safe than sorry.

Summary

  1. A very common food allergy, peanut allergy, affects a significant segment of the population.
  2. It occurs when the immune system identifies peanut protein as a harmful entity and triggers an immune response against it.
  3. A few genes that have been identified to have strong associations with peanut allergy. There is a better understanding of how some people are at an increased risk of developing the condition while others are not.
  4. The best way to manage peanut allergy or any food allergy, for that matter, is to avoid such foods. It is also advisable to have emergency antihistamines on hand in case you encounter the allergen accidentally.

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563476/
https://journals.plos.org/ploson/article?id=10.1371/journal.pone.0222440
https://www.healthline.com/health-news/researchers-discover-peanut-allergy-genes#Pinpointing-peanut-genes
https://genetics.thetech.org/ask/ask224

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