Abstract Anaphylaxis is an acute, potentially fatal systemic hypersensitivity reaction with varied mechanisms and clinical presentations. Although prompt recognition and treatment of anaphylaxis are imperative, both patients and healthcare professionals often fail to recognize and diagnose its early signs. Clinical manifestations vary widely, however, the most common signs are cutaneous symptoms, including urticaria and angioedema. Immediate intramuscular administration of epinephrine into the anterolateral thigh is first-line therapy, and is always safe even if the diagnosis is uncertain. The mainstays of long-term management include specialist assessment, allergen avoidance measures, and the provision of an epinephrine auto-injector with an individualized anaphylaxis emergency plan. This article provides an overview of the causes, clinical features, diagnosis, and acute as well as long-term management of anaphylaxis.

Key take-home messages • Anaphylaxis is the most severe form of a hypersensitivity reaction that is rapid in onset and potentially fatal. • Prompt recognition and treatment are critical in anaphylaxis. • The diagnosis is based primarily on clinical signs and symptoms. • The most common clinical manifestations are cutaneous symptoms, including urticaria, facial/lip swelling, erythema, and pruritus. • Referral to an allergist or immunologist should be considered for all persons who have experienced a previous anaphylactic episode. • Epinephrine is the drug of choice for anaphylaxis and should be given immediately, even if the diagnosis is uncertain; intramuscular administration into the anterolateral thigh is recommended. • There are no absolute contraindications to the use of epinephrine. • Up to 15% of anaphylaxis cases will have a biphasic response, with a second wave of symptomatology. • The mainstays of long-term treatment include: specialist assessment, avoidance measures, the provision of an epinephrine auto-injector and an individualized anaphylaxis emergency plan.