What is Pollen Allergy?
Pollen is one of the most common causes of allergies in the United States (US).
About 8% of adults and children in the US have pollen allergies.
Worldwide, 10-30% of the population is affected by this condition.
Pollen is a powdery substance that is transported from one plant to another to help in fertilization (reproduction). Pollen is made up of minute pollen grains.
Plants release pollen grains in the atmosphere, and these either travel through the wind or are carried by birds, animals, and insects to other plants. Light, dry, and small pollen grains can easily travel by the wind. Pollen grains are the most common causes of allergies.
Pollen allergy can be seasonal or year long. It is usually seen in most people during the growing seasons and depends on the specific pollen that you’re allergic to. During spring, there’s tree pollen in the air that some people are allergic to. Others may be allergic to grass pollen, especially during summer. Ragweed allergies usually occur in late spring or early fall.
Once pollen enters the human body, the immune system of people allergic to pollen considers it as a foreign and dangerous substance. The immunoglobulin E (IgE) cells are antibodies that are produced by the immune system in the presence of an allergen. When pollen comes in contact with IgE cells in the tissues of the nose and mouth, the tissues release chemicals like histamine and leukotrienes to alert the body.
Known for their peculiar barks that peel like paper, birch trees are found throughout the cool regions of Northern hemisphere.
Birch trees are wind pollinated. The levels of pollen are influenced by many factors including the weather, local flora diversity, etc. A single birch tree can produce up to 5 million pollen grains.
Other Food Allergies Caused Due To Birch Pollen Allergy
Oral Allergy Syndrome or OAS is a form of a contact allergic reaction triggered due to the consumption of certain raw fruits and vegetables. This is because your immune system mistakes the proteins present in these for pollen due to their similarity.
Some foods that cross-react with birch pollen allergy are:
Symptoms of Birch Pollen Allergy
These chemicals cause the body to respond with unpleasant allergic symptoms, including:
- Itch in the nose, eyes, mouth, and ears
- Runny nose
- Excess mucus production in the nose
- Itchy throat
Other Types of Pollen Allergy
There are thousands of different species of trees, plants, bushes, and shrubs that release pollen into the atmosphere. Some people can be allergic to a certain type of pollen but be alright when exposed to other types.
Here are some of the common types of pollen allergies found in the United States.
1. Grass pollen allergy
2. Ragweed pollen allergy
3. Oak pollen allergy
4. Cedar pollen allergy
The Genetics Behind Pollen Allergy
Changes or mutations in certain genes have been observed in people with birch pollen allergy. Studying these changes can help predict if a person has a higher risk for these allergies as compared to other people.
The CHI3L1 Gene
The CHI3L1 gene contains instructions for producing Chitinase-3-like protein 1, a glycoprotein. Glycoproteins are molecules that consist of a carbohydrate and protein.
CHI3L1 proteins are involved in both innate and adaptive immune responses.
Any changes in this gene can result in exaggerated immune responses to harmless substances found in environment, like tree pollens.
rs880633 one such change (or Single Nucleotide Polymorphism - SNP) found in the CHI3L1 gene.
People who carry the G allele for this SNP are at an increased risk for birch pollen allergy than those with the C allele.
Non-Genetic Risk Factors For Birch Pollen Allergy
Season - Late winter and spring seasons are when the pollen count in the atmosphere is very high. People experience pollen allergies the most during these seasons.
Climate changes - When plants produce more pollen, the pollen count in the atmosphere is high, and this increases the chances of pollen allergy flare-ups. Here are factors that affect pollen production.
- Air temperature
- CO2 (Carbon dioxide) in the atmosphere
- Intensity of sunlight
An increase in the global temperature has led to pollen grains being produced early in the plant cycle. This has also led to an extended pollination season. These, together, increase the risks of pollen allergy flare-ups.
Insect migration - The number of insects that carry pollen from one place to another has increased globally. Insects are migrating from one place to another in large numbers. This also increases the chance of getting allergies.
Increase in global humidity - Increase in humidity makes insects, dust mites, and molds more active. This, in turn, increases exposure to pollens.
Weather changes - Increased instances of thunderstorms and heavy rains cause breakage (fragmentation) of existing pollen in the atmosphere. This increases the pollen count and results in hay fever outbreaks.
External irritants - External irritants like aerosol spray, tobacco smoke, dust mites, wood smoke, and air pollution exposure can also trigger hay fever by making the nasal passage more sensitive to irritants.
Diagnosing Birch Pollen Allergy
A pollen allergy can usually be diagnosed easily, but you may need to consult an allergist sometimes to confirm the reaction and treat it.
Skin-prick test: A small amount of allergen is pricked into different areas of the skin. After 15-20 minutes, if signs of allergy like redness, swelling, and itchiness are observed, the person is said to be allergic to pollen.
Managing Birch Pollen Allergy
The best way to manage any allergy is to avoid the allergen causing it. This can prevent severe allergic reactions.
- Try to stay indoors on windy days.
- Wear a mask when pollen counts are reported to be high.
- Try to avoid gardening or yard work during peak growing season.
- Vacuum your house regularly using a vacuum with HEPA filters to eliminate any allergens.
- Wash clothes that you wear outside as pollen may stick to them.
- Try to avoid drying clothes outside as pollen may stick to them.
- Keep a squeeze bottle handy in case you inhale pollen and need to flush it out of your nose.
- Use air conditioning at home and in the car to avoid direct exposure to pollen.
Certain OTC medications like antihistamines and decongestants can help with allergy symptoms.
If OTC medications don’t help with symptoms, your doctor would recommend an allergy shot.
Allergy shots are basically a series of injections containing the allergen. The shots are meant to help your immune system get used to the allergen and reduce the severity of symptoms. A series of shots is needed overtime to help relieve symptoms.
Most people mistake OAS for food allergies and restrict the consumption of only those foods. It is important to get checked for OAS and avoid all the trigger foods.
- Birch pollen allergy is a reaction of the body’s immune system against pollen produced by the birch tree. Pollen allergy can be seasonal, during the growing season, or year long.
- The symptoms of birch pollen allergy include sneezing, cough, nasal congestion, itchy throat, and aggravation of asthma in certain cases.
- Changes or mutations in certain genes that regulate the body's immunity can result in exaggerated immune responses to harmless substances found in the environment like pollen.
- A few diagnostic tests like skin-prick test are available to test for birch pollen allergy.
- The best way to deal with any allergy is to avoid exposure to the allergen. Certain home remedies and OTC medications can help relieve symptoms. Allergy shots may be prescribed for severe cases where other remedies do not work well.
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