An allergy is an immune system overreaction to a substance that is harmless to most people. Your immune system tags that substance — pollen, dust mite protein, peanut, penicillin — as a threat and releases histamine, producing sneezing, itching, swelling or, at worst, a dangerous drop in blood pressure. Allergies are not a fixed childhood diagnosis. They can begin, worsen or fade at any age.
What Happens in the Body During an Allergic Reaction?
Your first exposure to an allergen usually causes no symptoms at all. Behind the scenes, the immune system produces immunoglobulin E (IgE) antibodies that attach to mast cells in your skin, gut, nose and airways. On a later exposure, the allergen binds to those antibodies, the mast cells rupture, and histamine floods the surrounding tissue. That is why a reaction can feel sudden even though the sensitisation happened months or years earlier.
What Are the Most Common Types of Allergies?
| Type | Common triggers | Typical symptoms |
|---|---|---|
| Respiratory (allergic rhinitis) | Dust mites, pollen, mould, pet dander, cockroach | Sneezing, blocked or runny nose, itchy watery eyes, post-nasal drip |
| Skin | Nickel, fragrance, hair dye, latex, certain plants | Hives, eczema flares, contact dermatitis, itching |
| Food | Milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish | Tingling mouth, hives, vomiting, cramping, swelling |
| Drug | Penicillin-type antibiotics, NSAIDs, sulfa drugs | Rash, hives, fever, swelling, breathing difficulty |
| Insect sting | Bee, wasp, hornet, ant | Large local swelling, hives, anaphylaxis |
Can You Develop Allergies as an Adult?
Yes, and it catches most people off guard. A move to a new city, a new pet, a renovation that stirs up dust and mould, a change of workplace or a new medication can all sensitise you well into midlife. Hormones appear to play a part too. Many women notice that nasal congestion, hives and skin sensitivity shift through pregnancy, perimenopause and menopause, and oestrogen is known to influence both mast cell behaviour and the moisture of the nasal lining. If your first real allergy season arrived in your forties, you are not imagining it.
Is It an Allergy or an Intolerance?
This distinction changes everything about how you manage it, and it is the one I correct most often in consultations.
- An allergy is an immune reaction. Even a trace amount can trigger it, symptoms come on within minutes to two hours, and it can be life-threatening.
- An intolerance is a digestive or enzyme problem, such as lactose intolerance. It is dose-dependent, causes bloating, wind and loose stools rather than hives or swelling, and is uncomfortable but not dangerous.
Lactose intolerance is very common in Indian adults and is frequently mislabelled as a milk allergy, which leads to far more restriction than necessary.
How Are Allergies Diagnosed?
An allergist confirms suspicion with a skin prick test, a specific IgE blood test, patch testing for contact dermatitis, or a supervised oral food challenge, which remains the gold standard for food allergy. Results are always read alongside your history — a positive test without matching symptoms does not mean you must avoid that food.
Be sceptical of IgG food sensitivity panels, hair analysis and applied kinesiology. Major allergy societies do not recommend them, and in my experience they are the single biggest cause of unnecessarily restricted, nutritionally poor diets in otherwise healthy women.
How Do You Manage Allergies Day to Day?
- Reduce exposure first. For dust mites, wash bedding weekly on a hot cycle, use mattress and pillow covers, and keep soft furnishings out of the bedroom.
- Rinse with saline. A daily nasal saline rinse clears allergens and mucus and reduces how much medication you need.
- Use a steroid nasal spray correctly. It is the most effective treatment for persistent allergic rhinitis, but it takes one to two weeks of daily use to work. Most people give up too early.
- Choose a non-sedating antihistamine for breakthrough symptoms rather than older drowsy formulations.
- Ask about immunotherapy if a specific allergen is confirmed. It is the only treatment that changes the underlying sensitivity rather than masking symptoms.
No diet cures an allergy. That said, correcting a vitamin D deficiency, eating oily fish or another omega-3 source regularly, and keeping fibre intake varied to support a diverse gut microbiome are sensible supports for immune regulation. Stress is a genuine amplifier too, so calming your nervous system is not a soft recommendation.
When Is an Allergic Reaction an Emergency?
Anaphylaxis needs adrenaline, not antihistamines. Call emergency services and use an adrenaline auto-injector into the outer thigh straight away if you notice:
- Difficulty breathing, wheeze or a tight chest
- Swelling of the tongue, lips or throat, or a hoarse voice
- Widespread hives together with vomiting or stomach cramps
- Dizziness, faintness or sudden collapse
Frequently Asked Questions
Can allergies go away on their own?
Some do. Many children outgrow milk and egg allergy, and hay fever often softens with age. Peanut, tree nut and shellfish allergies usually persist for life.
Do air purifiers help with allergies?
A HEPA purifier can reduce airborne pollen and pet dander in one room. It does little for dust mite allergen, which sits in bedding and carpets rather than floating in the air.
Can food allergies cause fatigue or brain fog?
True IgE food allergy causes fast, visible reactions, not vague tiredness. Persistent fatigue and brain fog deserve a proper workup for thyroid function, iron, B12 and sleep rather than an elimination diet.
Should I avoid a food because a test showed a positive result?
Not on that basis alone. Sensitisation on a test without symptoms on eating is common. Discuss the result with an allergist before removing anything from your diet.
About the Author
Nidhi Kakar is a nutritionist and the founder of Art of Wellness. She specialises in women’s health through the midlife years, from the mid-30s to the mid-60s, and has guided hundreds of women through perimenopause, menopause, and post-menopause with personalised nutrition and lifestyle plans.
This article is for educational purposes and does not replace personalised medical advice. If you suspect an allergy, ask your doctor for a referral to an allergist rather than self-diagnosing.
