Approximately 20% of the population will experience hives, also known as “urticaria,” at some point in their lives. Hives are raised welts that are typically quite itchy, occur anywhere on the body, and last for hours before fading and reappearing elsewhere. Swelling, which may accompany the hives or exist on its own is termed “angioedema” and typically affects the lips, eyelids, hands and feet.
Acute urticaria lasts less than six weeks and can be caused by food allergies, medication reactions, stinging insects, severe airborne allergic reactions, infections, and physical factors such as exercise. Chronic urticaria persists for more than six weeks, and in these cases the cause is more difficult to identify. Detailed history, physical exam, and appropriate skin and/or blood testing can help identify the cause. Keeping a food diary, a food elimination diet, or medication changes may be advised. Medications commonly used include non-sedating antihistamines and oral steroids in the case of severe, recalcitrant episodes. Xolair, an injectable medication was recently approved for use in severe chronic urticaria.