Urticaria

Urticaria, commonly known as hives, is a skin disorder characterized by transient, pruritic wheals (raised, red or skin-colored plaques) that result from superficial dermal edema and mast cell degranulation with release of histamine and other mediators. Individual wheals usually last less than 24 hours, but new ones can continue to appear, leading to ongoing flares. The condition may be accompanied by angioedema, deeper swelling of the face, lips, or eyelids, which can occur with or without wheals.

Urticaria is classified by duration and pattern. Acute urticaria lasts less than six weeks and is commonly triggered by infections, medications (such as nonsteroidal anti-inflammatory drugs or antibiotics), foods, insect stings, or exposures. Chronic urticaria persists for six weeks or longer and may be spontaneous (of unknown cause) or provoked by physical stimuli such as heat, cold, pressure, vibration, solar exposure, or cholinergic stimuli. In some cases, an autoimmune mechanism with autoantibodies to the IgE receptor or to IgE itself is suspected.

Diagnosis is clinical, based on history and examination. Tests are guided by features such as persistent symptoms, lack of response to treatment, or suspicion of alternative diagnoses (for example urticarial vasculitis or angioedema without wheals). Management focuses on symptom relief and trigger avoidance. First-line treatment uses second-generation H1 antihistamines, often at standard or higher doses, with adjuncts such as leukotriene receptor antagonists. Short courses of systemic corticosteroids may be used for severe episodes. Chronic refractory urticaria may respond to therapies including omalizumab or, in selected cases, cyclosporine. Most cases of acute urticaria resolve, while chronic urticaria can be intermittent and may require long-term management.