FACT SHEET

Urticaria (Hives)
  • Urticaria, also known as hives, is one of the most common skin conditions: an estimated 20 percent of Americans will have hives at some point in their lives.
  • The first sign of urticaria usually is sudden, severe itching, followed by the eruption of swollen red welts, or bumps on the skin, which sometimes are painful or cause a burning sensation.
  • The condition can occur anywhere on the body, and individual hives can vary in size from tiny to quite large and can join together. Each hive lasts no more than 24 hours, but new hives may erupt in another spot. Scratching makes the condition worse.
  • Urticaria can be acute or chronic.

Acute urticaria lasts from a few hours to six weeks and is more common in children and young adults. The cause or trigger often can be determined because hives typically develop a few minutes to a few hours after exposure.

Chronic urticaria lasts more than six weeks, may come and go for months or years and disappear on its own and is more common in middle-aged women. The trigger is identified only about 20 percent of the time.

  • Urticaria is classified as allergic or non-allergic.

Allergic urticaria: is caused by the immune system’s overreaction to a trigger; is more common in children than adults; and can be caused by foods (especially eggs, nuts and shellfish), medication (especially penicillin and sulfa drugs), infection, insect stings, blood transfusions or other substances.

Non-allergic urticaria: is the label given when an allergic source can’t be found; is more prevalent than allergic urticaria; and is caused by many things, including cold temperatures, food dyes and additives, medication, exercise, anxiety, constricting clothing (such as a belt or bra strap), the sun and stroking the skin with a firm object.

  • One episode of hives usually does not require medical attention. Patients should see a physician if they experience recurrent acute urticaria, chronic urticaria or urticaria complicated by swelling, difficulty breathing or other potentially serious problems.
  • A physician can help determine if a patient’s urticaria is allergic or non-allergic and recommend whether an allergist should be consulted. If a consultation is warranted, the allergist will review a diary of foods eaten, any unusual exposures and when the hives occurred.
  • The best way to manage urticaria is to avoid the trigger, if it can be identified. If avoiding the trigger is not possible, other measures can be taken to lessen exposure. For instance, patients with solar urticaria should wear protective clothing and apply sunscreen lotions when they go outdoors, and those with pressure urticaria can wear loose-fitting clothing.
  • Avoiding harsh soaps and frequent bathing can reduce the problem of dry skin, which can cause the itching and scratching that can aggravate urticaria. Vigorous toweling after a bath may trigger hives and should be avoided.
  • When an outbreak occurs, therapy may include an oral antihistamine or, in more severe cases, an adrenaline injection and possibly oral cortisone. Other medications may be prescribed depending on the type of urticaria.

The ACAAI has more information that can help you get your allergies and asthma under control. Call its toll-free number 800-842-7777 or visit www.acaai.org.