What should you know about late anaphylaxis?

Anaphylaxis is a rapid, serious allergic reaction affecting breathing, circulation, skin or the digestive system. Symptoms may include throat or tongue swelling, wheezing, difficulty breathing, widespread hives, dizziness, fainting, vomiting or sudden weakness. Symptoms can recur after they improve, sometimes without another obvious exposure. A delayed rash alone is not the same as anaphylaxis, but symptoms involving breathing, swelling or circulation need urgent action.

Possible triggers include foods, medicines, insect stings and other exposures. A clinician can review the event and consider allergy testing or a written emergency plan.

If anaphylaxis is suspected, use the person’s prescribed adrenaline auto-injector immediately, call emergency services, and state that anaphylaxis is suspected. Follow the device instructions. Keep the person lying down with legs raised if tolerated; allow a person struggling to breathe to sit with legs extended. Do not let them stand or walk. A second device may be needed if symptoms continue and the emergency plan allows it.

Treat breathing difficulty, wheezing, throat tightness, facial or tongue swelling, faintness or collapse as an emergency, even if the person feels better afterward. Emergency assessment is needed after adrenaline because symptoms can return. Do not rely on an antihistamine alone when breathing or circulation is affected.

Ask what may have triggered the reaction, how to use your auto-injector, whether you need more than one device, and which symptoms require a second dose. Discuss referral for allergy assessment, avoidance advice and an emergency action plan.