Urticaria, commonly known as hives, is a common skin condition that affects around one in five people at some point in their lives. It causes intensely itchy, raised welts called weals, which can be round, ring-shaped, or merge into larger patches. These welts may appear anywhere on the body, often after the skin is scratched, and although they can be uncomfortable, they usually disappear within 24 hours without leaving permanent marks. Hives develop when mast cells in the skin release histamine and other chemicals into the bloodstream, causing fluid to leak from tiny blood vessels and resulting in redness and swelling. Many people with urticaria also experience angio-oedema, a deeper swelling beneath the skin that commonly affects the lips, eyelids, hands, or inside the mouth. Unlike hives, angio-oedema is often painful rather than itchy. If swelling occurs without hives, it may indicate hereditary angio-oedema, a separate inherited condition that is not caused by histamine and requires different diagnostic tests and treatment.

Urticaria is classified according to how long it lasts and what triggers it. Acute urticaria lasts less than six weeks and is often linked to allergies, infections, medications, or food, while chronic urticaria persists for more than six weeks and usually has no obvious cause. Another form, known as physical urticaria, is triggered by environmental factors such as pressure on the skin, cold temperatures, sunlight, heat, exercise, or scratching. Stress and underlying medical conditions can also contribute to flare-ups. Although most cases improve on their own, persistent or severe symptoms may require treatment with antihistamines to reduce itching and swelling. In more serious cases, doctors may prescribe short courses of steroid tablets or recommend soothing creams to relieve discomfort. People with allergies or certain health conditions may have a higher risk of developing hives, making early recognition and appropriate care important. Understanding the different types, triggers, and treatment options can help individuals better manage symptoms, reduce recurrences, and seek medical attention promptly if swelling becomes severe or affects breathing.