Urticaria and Angioedema

Abstract

Urticaria and angioedema are common diseases with diverse origins that constitute a substantial component of medical practice. Urticaria, or hives, refers to one or more areas of intensely pruritic papules or plaques with swelling of the superficial dermis (wheal) surrounded by local erythema (flare). Angioedema refers to deep dermal subcutaneous swelling that may manifest as swelling of the mucosa of the face, tongue, pharynx, larynx, or intestines that can be alarming and, in some cases, life threatening. These conditions are heterogeneous in their presentation and chronicity. Although allergies are responsible for some cases, autoimmunity and dysregulation of the bradykinin system often play a significant role, leading to challenging diagnostic and therapeutic dilemmas. This review discusses the epidemiology, natural history, pathophysiology, diagnosis, and treatment of acute and chronic urticaria and angioedema. Emphasis is placed on physical triggers, the role of proper laboratory testing, and alternative agents for refractory cases. Emerging therapies for hereditary and acquired angioedema syndromes are also covered. Tables list the causes of acute and chronic urticaria, an escalating treatment approach for difficult cases, and a comparison of available parenteral therapies specific to bradykinin-mediated angioedema. Figures illustrate the mechanisms of urticaria, photographs of typical presentations, and an evidence-based diagnostic algorithm for clinicians. This review contains 9 figures, 8 tables, and 104 references.