What is Hay Fever?
Hay fever does not cause any fever or have anything to do with hay, as the name suggests. Hay fever, also called allergic rhinitis or nasal allergies, is an allergic response to certain allergens like pollen, dust mites, or pet dander. Allergic rhinitis occurs when the immune system responds to something foreign in the environment and mounts a defense causing cold-like systems. It mainly affects the nose.
The symptoms can occur with a change in seasons or even throughout the year, depending on the trigger allergen. Seasonal rhinitis usually occurs in response to outdoor allergens like pollen, especially in spring and fall. Pollen is the most common allergen that causes seasonal allergic rhinitis. Perennial rhinitis occurs at any time during the year or all year round in response to allergens like pet dander.
Irritants like cigarette smoke, perfumes, and other strong odors can also cause hay fever. These irritants cause nonallergic rhinitis that is similar to allergic rhinitis except for the trigger of symptoms.
Allergic rhinitis is not life-threatening but can interfere with your daily life and make you feel uncomfortable. Finding the right trigger and subsequent treatment are important to manage this condition.
Symptoms of Hay Fever
Common symptoms of hay fever include:
- Blocked or runny nose
- Sneezing and cough
- Itching in the nose, mouth, eyes, or throat
- Sore throat
- Red and watery eyes
- Swollen eyelids
- Headaches
- Fatigue
- Dry and itchy skin, which is a common symptom of eczema
- Sinus pain
Symptoms occur on immediate exposure to the allergen. Certain symptoms like headaches happen after a long time of exposure to the allergen. Symptoms last as long as you’re exposed to the allergen. A blocked or runny nose, along with sneezing and cough, are the most common symptoms.
The Genetics Behind Hay Fever
If there’s a history of allergies in your family, you’re more likely to get allergic rhinitis. If both the parents have asthma or eczema, the child is more likely to get allergic rhinitis. Variations in several genes have been found to play a role in the risk of allergic rhinitis. A few variations are listed below.
TSLP Gene
The TSLP gene encodes a protein called thymic stromal lymphopoietin, which is a cytokine. Cytokines are a category of proteins involved in immune cell signaling.
This protein promotes the maturation of certain cells called T helper type 2 (TH2) cells associated with diseases like asthma, allergic inflammation, and other allergic conditions.
rs1837253
rs1837253 is an SNP found in the TSLP gene. The minor allele, the T allele, is found to be associated with protection from asthma and a reduced risk of allergic rhinitis. The major allele, the C allele, is associated with an increased risk of hay fever with asthma.
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.
rs9273373
rs9273373 is an SNP found in the HLA-DQB1 gene. [The major allele, the G allele, is found to be associated with an increased risk of allergic rhinitis and asthma]
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4280183/).
Non-Genetic Factors that Influence Hay Fever
Few non-genetic factors that increase your risk of developing hay fever are:
- Working in an environment in which you’re constantly exposed to certain allergens like dust mites.
- Animal dander can cause hay fever in certain people. Living with pets can increase the risk of hay fever.
- Smoking cigarettes or exposure to smoke increase the risk of nonallergic rhinitis.
- Other allergies, atopic dermatitis, or asthma
- Living in an environment in which you’re constantly exposed to allergens
Diagnosing Hay Fever
Skin-prick test: A small amount of allergen is pricked into the skin of your arm or upper back. If a bump or hive is seen at the site of the prick after about 20 minutes, it could mean that you’re allergic to that particular material. The allergen is also sometimes inserted under the skin in an intradermal skin-prick test, which is more sensitive.
Blood test: Blood samples are tested for the presence of allergic antibodies. It’s also called the radioallergosorbent test (RAST).
Managing Hay Fever
Self-care: The best way to avoid symptoms is to avoid exposure to allergens. If you’re experiencing symptoms, try to trace back your activities and find the cause of the symptoms.
- Try to stay indoors as much as possible to avoid increased exposure to pollen, especially in the spring and fall seasons when pollen counts are maximum.
- Keep your house clean and free of dust mites. Clean the air conditioner vents frequently as they accumulate a lot of dust.
- Wash your bedding frequently and use mite-proof covers if necessary.
- If you’re allergic to pet dander, try to keep the pet outside your room as much as possible to avoid exposure to allergens.
- Avoid using carpeted floors at home as they tend to accumulate a lot of dust and dander.
- Acupuncture, honey, certain probiotics, and nasal saline injection are certain home remedies that can help in treating allergies.
Medication: Many allergens aren’t airborne and cannot be easily avoided. Certain medications or treatment can help manage symptoms. Consult a doctor before starting any new medication or treatment.
- Antihistamines are used to treat allergies. Various OTC antihistamines like cetirizine, fexofenadine are available.
- Decongestants are usually used for a short period to relieve a blocked nose and other sinus-related symptoms.
- Eye drops and nasal sprays are also used for a short period to treat red eyes and other allergy-related symptoms. Steroid nasal sprays are used long-term to treat severe allergies.
- Corticosteroids are used to help with inflammation and immune response. They are usually used in nasal sprays.
- Immunotherapy or allergy shots are usually recommended by the doctor for severe allergies.
Summary
- Hay fever, also called allergic rhinitis or nasal allergies, is an allergic response to certain allergens like pollen, dust mites, or pet dander. The immune system responds to certain allergens and causes symptoms of allergy.
- Runny or blocked nose, red and watery eyes, itching of the nose and eyes, headaches, and sore throat are some of the common symptoms of hay fever.
- Variations in certain genes are associated with the risk of hay fever. The C allele of rs1837253, an SNP found in the TSLP gene, and G allele of rs9273373, an SNP found in the HLA-DQB1 gene, are known to increase your risk for hay fever.
- A skin-prick test or blood test can be used to diagnose allergic rhinitis.
- Certain home remedies can help treat hay fever. Finding the trigger is important in treating this condition. A doctor may prescribe some medication or treatments to help with severe cases.
References
https://www.healthline.com/health/allergic-rhinitis#_noHeaderPrefixedContent
https://acaai.org/allergies/types/hay-fever-rhinitis
https://www.medicalnewstoday.com/articles/160665
https://www.ncbi.nlm.nih.gov/pubmed/24388013
https://www.genecards.org/cgi-bin/carddisp.pl?gene=TSLP
https://medlineplus.gov/genetics/gene/hla-dqb1/
https://www.snpedia.com/index.php/Rs1837253
