How Are Chronic Hives Diagnosed?

Medically Reviewed by Debra Jaliman, MD on March 05, 2024
Written by Terri D'Arrigo
2 min read

If you have hives that keep coming and going for weeks on end, and you don’t know what’s causing them, see a doctor. You could have what is called chronic idiopathic urticaria (CIU) or chronic spontaneous urticaria (CSU).

CIU is when a person has these breakouts almost daily for at least 6 weeks, with no known cause.

Your doctor will look for the cause of your welts. If they figure out what’s making you have them, you don’t have CSU.

It’s a process of elimination. They’ll want to rule out more serious conditions that can trigger hives, like hepatitis or an overactive thyroid. They’ll ask you about your medical history and your family’s medical history, and possibly do some tests.

If your doctor is able to rule out other conditions, they may refer you to a skin specialist or allergy specialist.

Things you’re exposed to every day, like food, medication, infections, plants, pet dander, and latex, can sometimes be the problem.

The doctor will want to know:

  • What kinds of things are you exposed to at home or work?
  • Do you have pets? Have you been around other people’s animals lately?
  • What medications do you take?
  • What kinds of foods do you eat regularly?
  • Do you notice that you get hives when you’re hot, cold, or sweaty?

It may be helpful to keep a diary for a few weeks to bring to your appointment. This will help your doctor rule things in or out.

To look for causes, you might get some of these tests:

Blood test. Your doctor takes some of your blood and sends it to a lab to look for illnesses or infections.

Biopsy. Your doctor removes a small piece of your skin to look at under a microscope. This is to see if an inflammation of the blood vessels, called vasculitis, may be the cause of your hives.

If you’re still having breakouts and the tests don’t point to a cause, your doctor will most likely say you have CIU.

Some people have outbreaks for several weeks, while others have them for years. They should eventually go away. Talk to your doctor about the best treatments to manage the itching and discomfort.