Hives - Definition and Overview

Urticaria or Hives is a relatively common form of allergic reaction that causes. Hives are a series of raised red skin welts, ranging upwards from 5 mm (about a 1/4 inch) in diameter, they itch severely, and often have a pale border. They are caused by direct contact with an allergenic substance (generally a plant, such as poison ivy), or an immune response to food or some other allergen. Some people suffer hives as a result of severe stress.

Urticaria also includes so called physical allergies. Some physical allergies include those due to water, heat, and the cold. - Cold Urticaria is the most common physical allergy whose primary symptom is localized hives on an area of the body exposed to the cold. Hives generally worsen when the cold area is warmed and symptoms usually show up a few minutes after contact with the cold and can last a short while to a few hours.