Anaphylaxis causes and symptoms

Foods, medicines, and insect stings are recognised triggers, although the cause is not always clear. Severe airway or circulation symptoms require immediate adrenaline and emergency help.

A reaction begins when the immune system releases chemicals after exposure to a trigger. Possible triggers include particular foods, prescribed or over-the-counter medicines, insect venom, and latex. Exercise or other contributing factors may be relevant in some episodes.

Anaphylaxis may present with throat or tongue swelling, hoarseness, wheezing, difficult breathing, sudden weakness, dizziness, fainting, confusion, hives, flushing, swelling, vomiting, cramping, or diarrhoea. Skin symptoms can help recognition, but their absence does not exclude a severe reaction.

Give the prescribed adrenaline auto-injector into the outer thigh as directed and call local emergency services. Follow the person's action plan, note when medicine was administered, and use a further device if symptoms persist and the plan or emergency dispatcher directs it.

Lay the person flat with raised legs if possible and do not allow standing or walking. A supported position with legs extended may be needed for severe breathing difficulty. Use the recovery position if they are unconscious but breathing, and begin cardiopulmonary resuscitation if normal breathing stops.

Treat tongue or throat swelling, noisy breathing, wheezing, struggling for breath, collapse, faintness, confusion, or loss of consciousness as an emergency after a possible allergen exposure. Do not wait for hives, and do not use how common a trigger is to judge urgency.

Emergency assessment remains necessary after apparent recovery. Later follow-up can investigate the trigger, review avoidance measures, check auto-injector technique, and produce a written plan for another episode.

Ask what the likely trigger was, whether specialist allergy testing is suitable, which products or medicines require avoidance, and what signs should trigger adrenaline. A detailed account of exposures, timing, symptoms, treatment, and photographs can make the assessment more informative.