Following up patients after treatment for anaphylaxis.

Anaphylaxis is defined as a severe, life-threatening, generalised or systemic hypersensitivity reaction. Diagnosis is based on the presenting symptoms and signs which classically develop rapidly, typically evolving over minutes but in some cases hours. Various combinations of airway and/or breathing and/or circulatory problems are possible, as well as urticaria, and hypotension. Skin and/or mucosal changes (typically urticaria and/or angioedema) are seen in around 75% of cases, but importantly these features alone are insufficient for a diagnosis of anaphylaxis. As soon as possible after successful emergency treatment, timed blood samples should be taken for the mast cell tryptase (MCT) test. Serum samples need to be taken within 1-2 hours but no later than 4 hours from the onset of symptoms. It is important to document the acute clinical features (record BP, respiratory rate etc) and the time course of the onset of symptoms/signs and their resolution. Because of the risk of relapse patients should be observed for 6-12 hours after the onset of symptoms. Children under 16 years should be admitted and supervised by a paediatrician. An adrenaline injector device for intramuscular use only, should be prescribed as an interim measure before referral to a specialist allergy clinic. Referral to a specialist allergy service (or specialist paediatric service), is strongly recommended. Diagnosis can be confirmed, and further investigations organised.