Hives generally:

  • Appear as small round wheals, rings or large patches and may change shape
  • Itch and may be surrounded by a red flare
  • Occur in batches, and often appear on the face or the extremities

Individual hives can last from 30 minutes to 36 hours. As some hives disappear, new hives may develop.

About 40 percent of people with chronic hives also have angioedema. Signs and symptoms of angioedema include large welts or swelling of the skin that may occur around the eyes and lips, hands, feet, genitalia, and inside the throat. Swelling in the throat can obstruct breathing and requires emergency treatment. Angioedema may itch less than hives do, but can cause pain or burning.

Symptoms may not occur all the time. They may come and go with no apparent trigger. For some people, certain conditions — such as heat, exertion or stress — can make symptoms worse.

When to see a doctor

Although chronic hives and angioedema usually aren't life-threatening, they can be debilitating — and in some cases are a sign of an underlying health problem.

See your doctor if you have:

  • Severe hives
  • Hives that don't respond to treatment
  • Hives that continue to appear for several days

Seek emergency care if you:

  • Feel lightheaded
  • Have difficulty breathing
  • Feel your throat is swelling
Sep. 17, 2011