Anaphylaxis

Anaphylaxis is a serious, immediate-type systemic hypersensitivity reaction affecting multiple organ systems and characterized at its most severe by bronchospasm, upper airway angioedema, hypotension, and collapse. Lifetime prevalence is estimated to be 0.05% to 2%, but while anaphylaxis can be life-threatening, fatal anaphylaxis is rare. Medication, foods, and insect stings are the commonest triggers. The cornerstones of emergency management are support of the airway and/or ventilation, supine positioning of the patient, epinephrine (adrenaline), and volume expansion. In the community setting, early administration of rescue epinephrine and contact with emergency services are of equal importance. Following an episode of anaphylaxis, prevention of further episodes requires identification of likely trigger(s) and cofactors, optimizing the management of comorbidities, allergen avoidance strategies, and immunotherapy if available. Patient education including an anaphylaxis action plan and an epinephrine autoinjector should be considered where an allergen may be encountered unexpectedly (food and insect sting anaphylaxis, idiopathic anaphylaxis).