Seasonal Allergies Explained
Red, itchy and watery eyes, sneezing and runny nose – only a few of the symptoms that can make warm summer days miserable to those with seasonal allergies (also termed hay fever or allergic seasonal rhinitis). But what are allergies and why do some of us have them? Can hay fever be managed? Read on to find out.
What is an allergy?
Allergy is an abnormal adaptive immune response where the immune system misidentifies a harmless substance (allergen) as a threat. In affected individuals, this misidentification elicits a response with symptoms ranging from mild discomfort to life-threatening anaphylaxis which can occur within minutes of allergen exposure. Common allergens are found in sources like peanuts, pollen and insect venom. These abnormal responses are classified into types depending on the mechanisms in which they occur. Most common allergies (hay fever, asthma, eczema, and food allergies) are classed as Type I hypersensitivities because they are mediated by IgE-antibodies.
What are seasonal allergies?
Seasonal allergic rhinitis occurs when airborne pollen from wind pollinated grasses, trees, weeds and plants is inhaled and comes in contact with immune cells in the airways. Hay fever is usually worst between late March and September, when pollen count is the highest. Runny nose, sneezing, coughing, red and itchy eyes – only a few symptoms of hay fever; whilst this may appear trivial at first, “it can significantly affect quality of life, work and school performance and attendance, and is a risk factor for the development of asthma” (Allergy UK, 2017).
How do allergies develop?
“The process through which a person’s body becomes sensitive to a given allergen is known as sensitisation” (British Society for Immunology, 2017). Allergies develop in two stages. In the first stage, a person encounters the allergen for the first time. The immune system mistakenly ‘sees’ an innocuous substance as unsafe and makes specific IgE-antibodies against it. These antibodies coat a type of cell known as mast cells, which contain inflammatory mediators, like histamine. Upon secondary exposure, the allergen cross-links adjacent IgE molecules on mast cells, leading to the release of chemicals, in particular histamine, which causes the clinical symptoms of swelling, rashes, shortness of breath and so on.
Why are some people allergic and other not?
Some people may have a greater allergic predisposition, a condition termed atopy. Atopic individuals are more likely to develop eczema, asthma and hay fever (the atopic triad) which develop in a sequence throughout the life-course. Scientists refer to this as the “atopic march” or “allergy march”. “Infants and children with gastrointestinal and cutaneous allergies have a 2‐ to 3‐fold increased risk of later developing asthma and hay fever” (Roitt et al., 2017) but further research is needed to determine whether this relationship is causal.
Whilst there are many factors that affect someone’s likelihood to develop allergies, finding a single causative link is a complex task. The ‘Old Friends Mechanism’ theory suggests that a diverse human microbiome helps ‘teach’ our immune system what is a threat and what is not. It’s been hypothesised that changes in our lifestyle, including less breastfeeding, smaller households, improved hygiene, antibiotic use/abuse, has reduced our exposure to microbes thus leading to increased immune vigilance and hypersensitivity. According to the British Society of Immunology (2017), “[this] is the most compelling theory for why allergies are increasing in the developed world”.
There is currently no cure or prevention measure for allergies like hay fever. However, steps can be taken to understand your allergies better and help manage the symptoms.
- Identify what is really setting you off with a quick allergen test
- Monitor pollen count and stay indoors whenever possible
- Put Vaseline around your nostrils to trap pollen
- Wash your clothes and shower after spending time outdoors
- Wipe your pet’s coat with a damp cloth after spending time outdoors
- Dry laundry indoors to minimise pollen on clothing
- Keep windows shut to minimise indoor pollen
- Vacuum regularly and clean surfaces with a damp cloth
- Consider using an air purifier with a HEPA filter
- Eat a varied diet and consider supplementing to ensure you’re getting the nutrients needed for a well-functioning immune system
- Book a consultation with one of our doctors to find the best recommendations to address your allergies
Rusne is a United Kingdom-based writer passionate about nutrition as treatment and prevention of illness. She is currently completing her Bachelor in Food Science and Nutrition at the University of Leeds, and has Research & Development experience in the reformulation of sugary soft drinks.
Apart from her studies, Rusne particularly enjoys cooking, travelling and exploring independent coffee shops.