Wheat allergy: symptoms, diagnosis and how it differs from coeliac disease

A food allergy happens when the immune system overreacts to a particular food. The NHS says it is not clear why this happens, but certain foods are more likely to cause an allergic reaction. Wheat is one of the foods it names among the most common, together with cows’ milk, eggs, peanuts, soybeans, peas and chickpeas, tree nuts and shellfish.

Because wheat is in so many foods, a wheat allergy can be harder to avoid than some other allergies. Bread, pasta, cakes and breakfast cereals are obvious sources, and the NHS notes that gluten, found in wheat, barley and rye, appears in certain sauces and some ready meals too. Reading ingredient labels is therefore the everyday task.

The NHS says you have a slightly higher chance of getting a food allergy if you or a close family member have other allergies, asthma or eczema.

These three are often confused. The NHS separates them clearly. A food allergy involves the immune system reacting to a food, with symptoms such as itchy skin, wheezing or swelling of the lips, face and eyes. A food intolerance, by contrast, is caused by difficulty digesting a food or ingredient, and the NHS says it is not caused by your immune system overreacting, which means you cannot have a serious allergic reaction.

Coeliac disease is different again. The NHS describes it as an autoimmune condition in which the immune system attacks the gut lining when you eat gluten, damaging the small intestine so the body cannot properly take in nutrients. It has no cure, and treatment is a lifelong gluten-free diet.

The NHS says symptoms of a food allergy can affect any part of the body, including different parts at the same time. Most are not serious, but they can be for some people. It lists the common symptoms below.

• Feeling dizzy or lightheaded.

• Itchy skin or a raised rash (hives).

• Swelling of the lips, face and eyes (angioedema).

• Coughing, wheezing, breathlessness, noisy breathing or a hoarse voice.

• Sneezing, or an itchy, runny or blocked nose.

• Feeling or being sick, tummy pain and diarrhoea.

The NHS says to see a GP if you think you or your child may have a food allergy. It says to call 999 if lips, mouth, throat or tongue suddenly swell, if breathing is very fast or hard, if the throat feels tight or swallowing is difficult, if skin, tongue or lips turn blue, grey or pale, if someone suddenly becomes very confused, drowsy or dizzy, or if someone faints and cannot be woken.

If you or the person you are with has an adrenaline auto-injector or nasal spray, the NHS says to use it immediately and call 999 afterwards, even if the person seems better. For anaphylaxis it says to lie down, raise the legs, and use a second injector if there is no improvement after 5 minutes. It says not to stand or walk, even if you feel better, and not to drive yourself to A&E.

The NHS says a GP who thinks you have a food allergy may refer you to a specialist for tests. These can include a skin-prick test, blood tests, or a special diet where you avoid the suspected food to see if symptoms improve. You may also be asked to keep a food and symptoms diary to help work out what is triggering your symptoms.

The NHS also warns that you should not cut foods out of your diet without speaking to a GP. For intolerance, it says some home tests that claim to diagnose food intolerances are not recommended because there is limited evidence they are accurate and they may suggest avoiding multiple foods, which can be harmful.

There is no treatment that removes a food allergy. The NHS says if you have one, you will not be able to eat the food you are allergic to, including foods where it is an ingredient. You will be given medicines to manage symptoms or for emergencies: antihistamines for mild reactions and adrenaline auto-injectors or a nasal spray for severe reactions. Your specialist will give you an allergy action plan.

Day to day, the NHS advises checking food labels and restaurant menus carefully, telling friends, family, nursery, school and work about your allergy, carrying two adrenaline auto-injectors or nasal sprays with you at all times if prescribed, telling staff at restaurants and cafes, and telling airlines and cabin staff before you fly.

Care is provided free through the NHS, usually starting with the GP and an allergy clinic. Private allergy clinics also offer testing and consultations, but the principles of avoidance, emergency medicines and an action plan are the same.