Urticaria, also known as hives, is an outbreak of swollen, pale red bumps or plaques (wheals) on the skin that appear suddenly -- either as a result of the body's adverse reaction to certain allergens (insect stings, sunlight exposure, etc.) or for unknown reasons.
Hives usually cause itching, but may also burn or sting. They can appear anywhere on the body, including the face, lips, tongue, throat, or ears. Hives vary in size (from pencil erasers to a dinner plate), and may join together to form larger areas known as plaques. They can last for hours, or up to one day before fading.
The best treatment for hives is to identify and remove the trigger, if you can figure out what that is. While you're waiting for hives and swelling to disappear, apply cool compresses or wet cloths to the affected areas. Try to keep clothing loose-fitting and lightweight.