Food allergies are immune reactions to food. They happen when the immune system reacts to a food protein as if it were harmful. Reactions can be mild, but some food allergies can cause anaphylaxis, a rapid and potentially life-threatening allergic reaction.
Food allergy is different from food intolerance. Allergy involves the immune system and can become dangerous quickly. Intolerance more often causes digestive or other symptoms without the same immediate anaphylaxis risk.
Common Triggers
Any food can cause an allergy, but common triggers include cow's milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, soya, sesame, celery, mustard and lupin.
Children may outgrow some allergies, such as milk or egg allergy, but others, including peanut, tree nut, fish and shellfish allergy, are more likely to persist.
Symptoms
Symptoms can appear within minutes, although delayed reactions can also happen. Common symptoms include itching or tingling in the mouth, hives, swelling of the lips, face, tongue or throat, wheezing, shortness of breath, feeling dizzy, nausea, vomiting, abdominal pain and diarrhoea.
Signs of a severe reaction include breathing difficulty, throat tightness, swelling affecting the airway, collapse, confusion, pale or clammy skin, and symptoms involving more than one body system. These may indicate anaphylaxis.
Anaphylaxis
Anaphylaxis needs immediate action. NHS advice is to use an adrenaline auto-injector if one is available, call 999 for an ambulance, and keep the person lying down unless breathing difficulty means they need to sit up slowly. A second auto-injector may be needed if symptoms do not improve after five minutes.
People at risk may be prescribed two adrenaline auto-injectors and referred to an allergy specialist. Family, friends, schools, workplaces and carers may need to know where the injectors are kept and how to use them.
Diagnosis
Diagnosis is based on the reaction history and, where appropriate, allergy testing. Tests may include skin prick testing, blood tests for specific IgE antibodies and supervised food challenge testing in specialist settings.
Unsupervised food challenges can be dangerous for people who may have severe allergy. A clear history is important because positive tests can show sensitisation without proving that a food causes symptoms.
Management
The main management is avoiding the confirmed allergen while maintaining a nutritionally adequate diet. This usually involves reading labels, understanding precautionary allergen statements, avoiding cross-contamination, and communicating clearly with restaurants, schools and carers.
Treatment depends on the reaction. Mild symptoms may be treated with advice from a health professional, while suspected anaphylaxis requires adrenaline and emergency medical help.
Labelling and Everyday Risk
Food labels and catering information are a major part of allergy management. In the UK, packaged food must highlight specified allergens in the ingredients list, and food businesses must provide allergen information for non-prepacked food.
People with food allergies often carry written plans, auto-injectors and safe snacks. The practical burden can be significant, especially for children, families and people with multiple allergies.
See Also
References
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