A Genetic Backstory To The Most Common Allergy: Hay Fever

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Find the report that covers the Hay Fever genes

Disclaimer: Presence of the trait or SNP in your report depends upon the marker being present in your DNA raw data.

What is hay fever?

Hay fever, also known as allergic rhinitis is an allergic condition that develops as a response to a wide range of indoor and outdoor allergens that can be inhaled. 

How do I know if I have hay fever?

Numerous allergens may trigger an allergic response.

The signs and symptoms that follow an allergic exposure, indicating hay fever are:

  • Sneezing
  • Nasal itching
  • Runny or stuffy (congested) nose
  • Watery and irritable eyes 
  • Cough
  • Postnasal drip

How do I know that I have hay fever and not the common cold?

There is a high chance of misinterpreting the condition as a common cold due to the close similarities in the symptoms of both; hence, it is necessary to know the difference for appropriate treatment.

There are certain features, in particular, which distinguish the common cold from allergic rhinitis:

ConditionCauseOne Distinguishing symptomOnset of conditionDuration of condition
Hay fever/Allergic rhinitisAllergensRunny nose discharge is wateryImmediately after exposure to the allergen  As long as there is exposure to the allergen 
Common coldVirusesRunny nose discharge is mucus1-3 days post-exposure to a virus4-7 days


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What causes hay fever?

There exists a wide range of allergens that are capable of triggering the allergy, a few of which are:

  • Indoor allergens- pet dander, dust mites, mold, etc.
  • Outdoor allergens- grass, trees, flowers, etc.

 The underlying cause for allergy has been identified as regular inhalation of an extremely tiny (smaller than the tip of a pin) dry protein called pollen.

Pollens are invisible and are usually smaller than 40 microns in diameter.

They are carried by air and enter the respiratory pathway on inhalation, and as a result, it gets lodged in the nose, causing immediate sneezing, itchy nose, etc.

What is the genetic background of allergic rhinitis?

Though the apparent reason for hay fever is the exposure to pollen, a person’s genetic makeup can make them more susceptible to developing this allergy.

A few genes underlying the reason behind an allergic reaction are- 

  • IL33
  • SMAD3
  • IL1R1
  • TLR1

 In hay fever, certain variant forms of the above genes are implicated:


The gene is a member of the Human Leucocyte Antigen family of genes that is responsible for secreting proteins that trigger an immune response by displaying foreign peptides to the immune system.

The single nucleotide polymorphism in HLADQB1 implicated in hay fever causes hyperactivity of the gene. Thus an immune response is elicited; consequently, harmless pollen is identified as a harmful foreign substance, resulting in an allergy.

GeneSNP IdRisk AlleleImplications of risk allele
HLADBQ1rs9273373GIncreased activity of immune system, recognizing pollen as an allergen.



IL33 gene is a part of the interleukin family and is responsible for the activation of various components of the immune system like basophils, eosinophils, and natural killer cells.

A mutation in the gene, found in hay fever leads to increased activity of IL33, thereby increased action of the immune system components, which results in an allergic outcome to exposure of mere pollens.

GENESNP IdRisk alleleImplications of risk allele
IL33rs72699186THyper-activation of immune system components.


The SMAD3 gene provides instructions to synthesize the SMAD3 proteins, which upon activation by TGFB protein plays a major role in the activation of various genes, in cellular processes like cell differentiation, proliferation, etc.

A mutation in this gene results in an increased differentiation and proliferation of immune cells.

GENERS IdRisk AlleleImplications of risk allele
SMAD3rs17294280GIncreased differentiation and proliferation of immune cells.


TLR1 (Toll-Like Receptor 1) encodes pattern-recognition receptors whose role is to recognize external pathogens and thereby activate appropriate immune responses.

The presence of T allele, the risk allele, leads to the sensitivity of pollen, therefore, hyper-activation of the corresponding immune response. 

GENERS IdRisk Alleleimplications of risk allele
TLR1rs4833095TPresents pollen as an harmful pathogen to the immune system.


The gene encodes for a particular cytokine protein of the interleukin receptor family.

It is involved in immune and inflammatory responses. 

A single nucleotide polymorphism in the gene triggers an allergic reaction to pollen.

GENERS IdRisk Alleleimplications of risk allele
IL1R1rs1097862AIncreases immunity of the body against potentially harmless substances like pollen.

How do you treat the allergy?

Managing the condition is a major treatment approach in allergies; hay fever can be managed by taking certain measures:

  • Avoid using window fans
  • Wear pollen masks
  • Avoid drying clothes in the outdoors
  • Keep bed linen, pillow covers, carpets, etc. clean
  •  Avoid close contact with your pet

Treatment options for hay fever include:

  • Intranasal corticosteroids
  • Antihistamine drugs
  • Decongestants
  • Nasal sprays
  • Eye drops

A diet to manage hay fever:

Including a few vegetables and fruits to your diet will help in alleviating the symptoms of allergy:

  • Onions
  • Garlic
  • Tomatoes
  • Broccoli
  • Pineapple
  • Apple
  • Kiwi
  • Oily fish
  • Seeds
  • Turmeric
  • Herbal tea

This might be of help to you: A Guide To Analyze Your DNA Raw Data For Allergy



  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4280183/

Do you have your DNA raw data from 23andMe, AncestryDNA, FTDNA, MyHeritage?

Upload your DNA raw data to Xcode Life. Our Gene Allergy report analyzes hay fever, dust mite allergy, pollen allergy, and 13 other such traits.


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