Urticaria is the medical term for hives - pale, red swelling or "wheals" that occur in groups on any part of the skin and usually last a few hours before fading without a trace. New areas of hives may develop as old areas fade. The hives can range in size from as small as a pencil eraser to as large as a dinner plate and may join together to form larger areas of swelling. Hives are usually itchy, but may also burn or sting.
Hives are very common. Between 10 and 20 percent of people have at least one episode in their lifetime. Hives are formed by the release of a chemical called histamine into the skin. Allergic reactions, chemicals in foods or medications can cause histamine release but sometimes the cause is impossible to find. Hives usually go away within a few days or weeks, but occasionally last for many years.
When hive form around the eyes, lips or genitals, swelling can be excessive and frightening; however, the swelling usually subsides within 24 hours.
Acute urticaria is a type of hives lasting less than six weeks. With this type of hives the cause can usually be found. Foods, drugs or infections are the most common causes. Insects bites and internal disease may also be responsible.
Foods: Nuts, chocolate, fish, tomatoes, eggs, fresh berries and milk are the common foods that cause hives. Food additives and preservatives may also be the cause. Hives caused by food may appear within minutes or up to two hours after eating.
Drugs: Almost any medication can cause hives. Prescription antibiotics, pain medications, sedatives, tranquilizers and diuretics can all be potential causes as can non-prescription antacids, vitamins, eye and ear drops, laxatives, vaginal douches or other products. Tell your dermatologist about all medications and preparations you use to assist in pinpointing the cause of your hives.
Infections: Many different types of infections can cause hives. Colds are a common cause in children.
Chronic Urticaria is a case of hives lasting more than six weeks. The cause of chronic urticarial is more difficult to identify. Your dermatologist will need to ask many questions to find a possible cause, and even then, a cause for chronic hives is found in only a few patients.
Physical Urticarias are hives caused by sunlight, cold, pressure, vibration or exercise. Hives due to sunlight are called solar urticarial, a rare condition in which hives form within minutes of sun exposure and fade in one to two hours. Hives due to cold are common and appear when the skin is warmed after exposure to the cold. If large areas of the body are exposed to cold, wheezing, flushing, generalized hives and fainting may occur. In about 5 percent of the population, hives can form after firmly stroking or scratching the skin. If these hives occur along with other forms of hives, finding and eliminating the cause usually clears the condition. Otherwise it may last for months or year.
Treatment for hives starts with finding and removing the cause of the outbreak. This is not always easy and your dermatologist will need to ask many questions about your diet, medications, general health to determine the most likely cause.
Antihistamines are usually prescribed to provide relief from itching and other symptoms. These medications work best if taken on a regular schedule to prevent hives from forming. To determine which antihistamine works best for you, your dermatologist may try more than one antihistamine or combinations of these medications.
In severe cases, an injection of epinephrine (adrenalin) or a cortisone medication may be necessary.