Urticaria, commonly known as hives, is a skin condition marked by red, raised, and itchy welts that may appear in clusters across various parts of the body, including the face, arms, legs, and trunk. While these welts typically resolve on their own within hours or days, they can sometimes reappear and significantly affect a person’s quality of life. Though often harmless, the appearance and discomfort caused by urticaria can be distressing.

The condition occurs when mast cells in the body release histamine and other chemicals into the bloodstream. This leads to leakage of fluid from small blood vessels into the skin, causing the typical swelling and redness seen in hives. A defining trait of urticaria is the evanescent nature of the welts — they often disappear within 24 hours without leaving marks, though new ones may form elsewhere.

Symptoms include raised, often red lesions called hives, intense itching (pruritus), and in some cases, angioedema — swelling of deeper layers of the skin. Angioedema typically affects areas like the lips, eyelids, hands, or feet and can cause discomfort. Swelling involving the throat or tongue can be serious and may require emergency medical care due to the risk of breathing difficulties.

Urticaria is generally categorized based on how long symptoms last. Acute urticaria lasts less than six weeks and is usually triggered by identifiable factors. Chronic urticaria persists beyond six weeks and may occur without a known cause. Another category, physical or inducible urticaria, is triggered by specific physical stimuli like cold, pressure, sunlight, or heat.

Common causes of acute urticaria include allergic reactions to foods, medications, or insect bites; infections; physical triggers; and stress. Chronic cases may be linked to autoimmune processes, though the exact cause is often unclear.

Treatment focuses on symptom relief and avoiding triggers. Antihistamines are the primary treatment, helping reduce itching and swelling. In more severe cases, short-term corticosteroids may be prescribed. Identifying and avoiding known triggers is key to preventing recurrences.