Why anaphylaxis can be life-threatening

Immune chemicals released during anaphylaxis can make tissues swell, narrow the airways and cause blood vessels to widen. Airway swelling can block airflow, while vessel changes can reduce blood flow to the brain and other organs. Symptoms may therefore escalate from itching or flushing to a hoarse voice, wheezing, laboured breathing, dizziness, confusion or collapse.

A severe reaction may occur without obvious hives. The combination of sudden illness after a possible allergen and problems involving breathing or circulation should be treated as anaphylaxis rather than watched at home.

Use the prescribed epinephrine auto-injector immediately, then call local emergency services and state that anaphylaxis is suspected. Follow the device directions and the person's written action plan. Keep the person lying down with elevated legs when feasible; support them sitting with legs extended if lying down makes breathing harder. Sudden standing can worsen circulatory symptoms.

If the person becomes unresponsive and is not breathing normally, begin cardiopulmonary resuscitation if you know how and follow instructions from the emergency operator. Use another auto-injector if symptoms persist or return and the action plan or emergency operator directs this.

Call immediately for tongue or throat swelling, difficulty speaking or swallowing, noisy breathing, wheezing, blue or pale skin, faintness, confusion, collapse, or fast-spreading symptoms. Improvement after epinephrine does not remove the need for hospital assessment. Clinicians may monitor breathing and circulation because symptoms sometimes recur after seeming to settle.

Ask for a written plan covering your early warning signs, correct injector technique and circumstances for a further dose. Review possible triggers, the value of specialist allergy testing, safe alternatives to any suspected medicine, and storage of auto-injectors away from excessive heat. Close contacts should know where the devices are kept.