Urticaria

Urticaria is a common skin condition characterized by the sudden appearance of itchy, raised welts or hives on the skin. These welts can vary in size and shape and often have a pale center with a red border. The condition affects the skin and immune system, causing an allergic-type reaction that leads to swelling and redness. It can occur anywhere on the body and usually lasts for a few hours to a day before fading. The main health impact is discomfort from intense itching and swelling, which can interfere with daily activities and sleep. Sometimes, triggers such as certain foods, medications, or infections cause the reaction. In rare cases, it may be part of a more serious allergic reaction affecting breathing.

Urticaria is defined as a transient, pruritic, edematous skin eruption resulting from the release of histamine and other inflammatory mediators from activated mast cells in the dermis. It is commonly caused by IgE-mediated hypersensitivity reactions to allergens, but can also result from non-immunologic triggers such as physical stimuli or infections. The hallmark lesion is a wheal, a sharply demarcated, erythematous, and edematous plaque that typically resolves within 24 hours without residual skin changes. Chronic urticaria is defined by lesions persisting or recurring for more than 6 weeks and may involve autoimmune mechanisms. The condition is clinically significant due to its impact on quality of life and potential association with anaphylaxis in severe cases. Diagnosis is primarily clinical, supported by history and exclusion of other causes of pruritic rash.