What should you know about effects of anaphylaxis?

This severe allergic reaction can cause swelling of the lips, tongue or throat, wheezing, a tight throat, hoarse speech or difficulty breathing. Blood vessels may widen, causing dizziness, weakness, confusion or collapse. Hives, flushing, itching and swelling can appear on the skin. Nausea, repeated vomiting, stomach cramps or diarrhoea may also occur. Symptoms can involve more than one body system and may worsen quickly; a rash does not have to be present.

Use an adrenaline auto-injector if one has been prescribed, following its instructions, and call emergency services immediately. Keep the person lying down with legs raised if comfortable; someone struggling to breathe may sit with legs outstretched. Do not let them stand or walk. A second injector may be needed if symptoms continue and emergency help has not arrived. Follow-up assessment can identify triggers such as a food allergy and help plan future avoidance and emergency care.

Treat sudden breathing difficulty, throat or tongue swelling, faintness, confusion, collapse, or symptoms after a known allergen as an emergency. Call for help even if the person seems better after adrenaline, because symptoms can return and observation may be required. Anyone who has had a suspected episode should arrange medical review for trigger assessment and an emergency action plan.

Ask which symptoms should prompt an injector, whether you need more than one device, how to check its expiry, and whether allergy testing is appropriate. Ask how family, school or work colleagues should respond and which suspected triggers should be recorded.