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 come and go for several days.

What Causes Urticaria?

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

What Is Chronic Urticaria?

Hives that last for more than six weeks and may recur frequently over several months or 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.

How Is Urticaria Treated?

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