Hives or welts are quite common. More than 20% of people in the United States experience at least one episode of hives during their lifetime. Hives can be localized around the waist, on palms of the hands or the bottom of the feet, around the neck, or generalized in which case the whole body is covered with welts. In severe cases swelling of the eye lids, lips, tongue, and throat can occur (also called angioedema).

Hives can have many causes such as allergies to foods, medication, animal dander, latex, house dust, house dust mites, mold, and pollen. Hives can also be caused by physical factors such as heat, cold temperature, pressure to the skin, exercise, and sweating. In addition, hives can be caused by acute or chronic infection, or stress. All patients with hives should be evaluated by board certified allergist. Allergy testing should be performed in order to determine whether or not hives are caused by allergies.