Hives are characterized as itchy red, raised welts (also known as wheals) on the skin's surface that can spread or join together and form larger areas of raised lesions. They are generally triggered by exposure to an allergen or chemical irritant. They tend to appear suddenly and often disappear equally as suddenly.
Hives are usually an allergic reaction to food, medicine or infections. They can also be triggered by sun exposure, stress, excessive perspiration or other, more serious diseases, such as lupus. Anyone can get hives. They are not contagious. Hives may itch, burn or sting. They can vary in severity from a minor nuisance to potentially life threatening when associated with swelling of the tongue or larynx. Your dermatologist may prescribe antihistamines or oral corticosteroids. The best way to prevent hives is to discontinue exposure to the allergic irritant.
Hives lasting more than six weeks are known as chronic urticaria. The causes of chronic urticaria are different than in the acute setting and can be difficult to determine in many cases.