Learn what causes food allergies, the common allergens, symptoms including anaphylaxis, how allergies are diagnosed and how to manage them safely.
Food allergies happen when your immune system mistakes a protein in a food as harmful and reacts to it. Symptoms can range from itching, hives and swelling to vomiting and, in severe cases, anaphylaxis, which is a medical emergency. The most common triggers include milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, soya and sesame.
Living with a food allergy, or caring for a child who has one, can feel worrying at first. With an accurate diagnosis, careful label reading and a clear emergency plan, most people manage their allergies safely. This guide explains the causes, symptoms, diagnosis and day-to-day management of food allergies.
What are food allergies?
When someone with a food allergy eats (or sometimes touches) a trigger food, their immune system releases chemicals such as histamine. These cause the symptoms of an allergic reaction, usually within minutes to two hours.
Types of food allergy
- IgE-mediated allergy: the most common type, with symptoms that appear quickly. This type can cause anaphylaxis.
- Non-IgE-mediated allergy: symptoms develop more slowly, often hours later, and mainly affect the gut or skin. It is more common in babies, for example with cow’s milk allergy.
Food allergy vs food intolerance
A food intolerance, such as lactose intolerance, does not involve the immune system. It can cause uncomfortable digestive symptoms like bloating and diarrhoea, but it is not life-threatening. Coeliac disease is different again: it is an autoimmune reaction to gluten. Learn more in our guide to coeliac disease.
What are the most common food allergens?
Any food can cause an allergy, but a small group of foods is responsible for most reactions.
| Allergen | Where it may be hidden |
|---|---|
| Milk | Ghee, paneer, laban, baked goods, sweets, some breads |
| Eggs | Cakes, mayonnaise, glazes, some pasta and noodles |
| Peanuts | Sauces, satay, snacks, some sweets and baked goods |
| Tree nuts | Baklava, mithai, pesto, kormas, nut oils, marzipan |
| Sesame | Tahini, hummus, halva, breads and za’atar mixes |
| Fish and shellfish | Fish sauce, stocks, some Asian dishes |
| Wheat | Bread, chapati, pasta, couscous, sauces thickened with flour |
| Soya | Soy sauce, tofu, processed foods, some vegetarian products |
Many children outgrow milk and egg allergies. Peanut, tree nut, fish and shellfish allergies are more likely to last into adulthood.
What are the symptoms of food allergies?
Mild to moderate symptoms
- Itchy mouth, throat or ears
- Raised, itchy rash (hives)
- Swelling of the lips, face or eyes
- Tummy pain, nausea, vomiting or diarrhoea
- Sneezing or a runny nose
Signs of anaphylaxis
Anaphylaxis is a severe, life-threatening reaction. Signs include swelling of the tongue or throat, difficulty breathing or swallowing, wheezing, a hoarse voice, feeling faint or dizzy, collapse, and pale or floppy skin in children. If you suspect anaphylaxis, use an adrenaline auto-injector if one has been prescribed and call local emergency services immediately.
How are food allergies diagnosed?
If you think you or your child has a food allergy, see your doctor. They will ask about your symptoms and what you ate, and may refer you to an allergy specialist. Tests may include:
- Skin prick tests: a tiny amount of the food is placed on the skin to look for a reaction.
- Blood tests: measuring specific IgE antibodies to certain foods.
- Supervised food challenge: eating gradually increasing amounts of a food under medical supervision.
Be cautious about tests sold online or in shops, such as IgG food sensitivity tests, hair analysis or kinesiology. These are not recommended for diagnosing food allergy and can lead to unnecessary food restrictions.
How to manage food allergies day to day
Read food labels carefully
Many countries require major allergens to be clearly listed on packaged foods. Check labels every time, as recipes can change. Statements such as “may contain” warn of possible cross-contact.
Eat out safely
Always tell restaurant staff about your allergy before ordering, and ask how dishes are prepared. Be especially careful with sauces, desserts and fried foods cooked in shared oil. Our article on the food service industry explains how businesses handle allergens.
Have an emergency plan
- Carry any prescribed adrenaline auto-injectors at all times, and check expiry dates.
- Make sure family, school staff and friends know how to recognise and respond to a reaction.
- Consider wearing a medical alert bracelet.
Keep your diet balanced
Avoiding foods can lead to nutrient gaps. For example, a child avoiding milk needs other sources of calcium, such as fortified plant milks. A nutrition professional can help you plan a balanced, safe diet.
Introducing allergens to babies
Current guidance suggests introducing common allergens such as egg and peanut (as smooth peanut butter, never whole nuts) from around six months, one at a time, alongside other solid foods. If your baby has severe eczema or an existing allergy, speak to your doctor first. See our guide to newborn nutrition for more on feeding babies.
Free download: want an easy week of gut-friendly meals using everyday foods? Get our free 7-Day Gut-Friendly Meal Plan.
When to see a doctor or nutrition professional
- You or your child react repeatedly after eating a particular food
- You have had swelling of the lips or face, or a widespread rash after eating
- You are avoiding several foods and worry about your nutrition
- Your baby has severe eczema, poor growth or ongoing digestive symptoms
- Any sign of breathing difficulty, throat swelling or collapse. Call emergency services immediately.
Frequently asked questions
Can you develop a food allergy as an adult?
Yes. Although most food allergies start in childhood, adults can develop new allergies, most often to shellfish, fish, tree nuts or certain fruits.
Can food allergies be cured?
There is currently no cure for most food allergies. Some children outgrow them, and specialist treatments such as oral immunotherapy may be offered in certain cases under strict medical supervision.
Is a food allergy the same as a food intolerance?
No. Allergies involve the immune system and can be dangerous, while intolerances mainly cause digestive discomfort. Your doctor can help you work out which you have.
Get personalised nutrition support
Managing a food allergy should not mean a boring or unbalanced diet. Dr. Rida Saeed helps adults and families plan safe, nourishing meals that avoid trigger foods without missing key nutrients. Learn more about our food allergy and sensitivity service or book an online consultation via WhatsApp +971 54 448 6145.
This article is for general information only and is not a substitute for medical advice. Please speak to your doctor or a qualified health professional about your individual needs.
Free downloads
Practical guides from Dr. Rida Saeed
Get our free 7-Day Gut-Friendly Meal Plan or the PCOS-Friendly Food List — everyday South Asian and Middle Eastern foods, easy swaps and printable shopping lists.
Have a question about this topic?
Send it to Dr. Rida’s team — we reply within 24 hours.
Dr. Rida Saeed
Dr. Rida Saeed is a nutritionist offering online nutrition consultations for clients in the UAE, Pakistan and worldwide. She helps with gut health, PCOS and hormones, fertility and pregnancy, weight management and diabetes through practical, personalised diet plans. Book on WhatsApp +971 54 448 6145.
