Definition:
Hives are raised, itchy red or pink welts on the surface of the skin. Superficially, they may resemble insect bites, but they often occur over a large area. Hives may appear due to the release of histamine as part of an allergic reaction to a variety of substances, both food and non-food.
A related condition, angioedema, causes swelling of the blood vessels under the skin and may result in pain and redness.
Also Known As: urticaria
