How to treat anaphylaxis

Anaphylaxis can narrow the airway, impair breathing and lower blood pressure. Adrenaline acts on these dangerous changes, which is why it is the first-line emergency medicine. A prescribed auto-injector is designed for rapid use by the person having the reaction or someone nearby.

Antihistamines can help itching or hives, but they do not reverse airway obstruction or shock and must not delay adrenaline. Inhalers may ease wheezing for some people, yet they also do not replace adrenaline when several systems are involved or throat and circulation symptoms occur.

Use the auto-injector in the outer thigh according to its instructions, then call emergency services and state that anaphylaxis is suspected. Note when the medicine was given. Remove an ongoing trigger only when this is quick and safe, such as stopping an infusion being administered by a trained professional.

Lay the person flat and do not let them stand or walk. If breathing is difficult, allow sitting with legs extended; place an unconscious person who is breathing on their side. Follow the allergy action plan and dispatcher guidance about another injector if severe symptoms continue. Start cardiopulmonary resuscitation if the person is unresponsive and not breathing normally.

Call emergency services immediately for difficult or noisy breathing, throat or tongue swelling, a hoarse voice, persistent wheeze, sudden faintness, confusion, collapse, or pale, blue or grey lips. Do the same for a rapidly worsening allergic reaction involving more than one body system.

Emergency department assessment is required after adrenaline, including when the person feels fully recovered. Clinicians can provide oxygen, fluids and additional medicines when needed, monitor for recurrence and help arrange replacement injectors and allergy follow-up.

Confirm the suspected trigger, what should be avoided pending assessment, and whether an allergy specialist referral is suitable. Ask for a written action plan, prescriptions for replacement auto-injectors, device-specific training, storage advice and a clear explanation of when another dose may be needed.