Urticaria (Hives)

Urticaria, which is also known as hives, is a red, itchy skin rash with a raised white area in the center that can appear anywhere on the body. It is often mistaken for blisters, but does not contain fluid.

Urticaria usually goes away in 24 hours, but it may last several days.

Hives can be an allergic reaction to:

  • Foods 
  • Medicines 
  • Insect stings 

Hives may be triggered by:

  • Cold or heat 
  • Infections (usually viral) 
  • Other illnesses
  • Sun exposure
  • Physical exercise

Hives that last for more than six weeks and may last months for years. There is no known cause for most cases of chronic urticaria. 

Some of the known causes include: 

  • Antibodies that react with the tissue in the body
  • Certain kinds of infection

Your doctor may order blood tests to help determine the cause of the hives.

  • Antihistamines
  • Severe cases may require treatment with steroids.
  • A small number of patients with chronic urticaria may require other
    medicines to control their hives.

Last Updated 08/2012