Acute and Chronic Urticaria: Evaluation and Treatment.

Urticaria is a common dermatologic sign of a variety of diseases seen in primary care settings. It can affect skin on any part of the body and is primarily mediated by histamine release from mast cells. Urticaria, with or without angioedema, is classified as acute or chronic. Acute urticaria, defined as lasting less than 6 weeks, is self-limited. Diagnostic testing is typically not required for acute urticaria; limited investigation is recommended for chronic urticaria. H1 antihistamines are the initial pharmacologic agent used to provide relief from symptoms of acute urticaria. Second-generation H1 antihistamines are preferred over first-generation because of fewer sedating effects. Short courses of oral corticosteroids may be used if there is minimal or no response to antihistamines. First-line treatment of chronic urticaria should follow a stepped plan that includes second-generation H1 antihistamines, increasing the dose up to four times if needed. Recommendations for the use of H2 blockers and leukotriene receptor agonists are conflicting; however, if there is minimal or no response to a second-generation antihistamine, leukotriene receptor agonists or other immunosuppressants are recommended. Long-term corticosteroids are not recommended for chronic urticaria. Omalizumab is approved by the US Food and Drug Administration for the treatment of refractory chronic urticaria. Due to their safety profile, second-generation H1 antihistamines should be used in pregnant and breastfeeding individuals, children, and older adults.