Urticaria

The primary pathophysiologic mechanism involves mast cell degranulation and histamine release in the superficial dermis.

Chronic spontaneous urticaria is defined by the presence of symptoms for greater than 6 weeks without an identifiable external trigger.

First-line treatment for symptomatic urticaria is second-generation H1-antihistamines such as cetirizine, loratadine, or fexofenadine.

Dermatographism is the most common form of physical urticaria, characterized by the development of wheals following mechanical stroking of the skin.

Angioedema involves deeper dermal and subcutaneous tissue swelling and must be evaluated for airway compromise if involving the lips, tongue, or pharynx.

ACE inhibitor-induced angioedema is a bradykinin-mediated process that does not typically present with concurrent urticaria or pruritus.