Do you get hives and do they keep coming back? We bet you aren't sure why. This is because you may have a condition called Chronic Idiopathic Urticaria. About 20% of people get itchy red or skin-colored welts (also known as urticaria) at some point. For most people, they’re caused by an allergic reaction to a food or drug, and they go away quickly.

A small number of people tend to have these hives come back again and again without any known cause. If this condition lasts 6 weeks or more with new outbreaks on a nearly daily basis, the condition is called chronic idiopathic urticaria. Less than 1 percent of people have it. It's most common in people between the ages 20 and 40. 

A single outbreak usually lasts no more than 24 hours. Experts still aren't sure what causes CIU. The immune system seems to play a role. Some people develop chronic hives at the same time as other problems like thyroid. 

Experts don’t know what causes CIU. The immune system seems to play a role. And some people develop chronic hives at the same time as other problems like thyroid disease, hormonal problems, or cancer.

What are some common triggers? Doctors can't say for sure what causes CIU. They do know things that can lead to flare-ups:

-alcoholic drinks

-tight clothing

-nonsteroidal anti-inflammatory drugs (NSAIDS) such as aspirin and ibuprofen

-exercise

If you've had an outbreak for several weeks and you don't know why, see your doctor. She'll want to know when and where they pop up. She'll want to know if you're taking new meds. She'll ask about the foods you eat and if you have pets to see if an allergy is to blame. 

CIU isn't contagious. Yes, it's itchy and painful, it isn't dangerous.