Hives (Urticaria)

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What Is Urticaria?


Top Things to Know About Hives


Doctors put hives into two categories:

  1. Acute hives: when the condition lasts for less than 6 weeks (also called “acute urticaria”).
  2. Chronic hives: when the condition lasts for longer than 6 weeks (“chronic urticaria”).

How Do You Know It’s Hives?


  • Hives often itch or sting.


What Causes Hives?


The red blotches happen when cells in the bloodstream (called mast cells) release the chemical histamine. This causes tiny blood vessels under the skin to leak. The fluid pools within the skin to form spots and larger blotches.

Acute Hives

When an allergic reaction causes hives, they usually show up within minutes. Things (called triggers) that can cause someone to have hives include:


  • infections, including colds
  • anxiety or stress
  • exposure to the sun
  • exercise
  • contact with chemicals
  • scratching


Chronic Hives


How Do Doctors Diagnose Hives?

Usually a doctor will look at a person’s skin and be able to say it’s hives without doing anything else. With chronic hives, the doctor will ask more questions to find out why they’ve been going on for so long. He or she also may do some tests, like blood tests or allergy tests, to rule out other conditions.



  • your daily activities
  • everything you eat and drink
  • where hives appear on your body

How Are Hives Treated?

Some cases of hives go away on their own without treatment. If something is definitely causing a person to get hives, the doctor will recommend avoiding that trigger.

If hives are very itchy, the doctor may recommend taking an antihistamine medicine to block the release of histamine in the bloodstream. For chronic hives, doctors may prescribe a non-sedating (non-drowsy) or over-the-counter antihistamine to take every day.

The same medications don’t work for everyone, though. If you have chronic hives, it can take time and patience for you and your doctor to figure out the right treatment. If a non-sedating antihistamine doesn’t work, your doc might suggest a stronger antihistamine or another medication or a combination of medicines.

In rare cases, a doctor may prescribe a steroid pill or liquid to treat chronic hives. Usually, this will only be done for short periods (5 days to 2 weeks).

When It’s an Emergency


Fortunately, serious attacks of hives are extremely rare. Most of the time, hives are completely harmless and go away on their own. Even chronic hives can sometimes clear up on their own within a few months to a year.

Reviewed by: Rupal Christine Gupta, MD
Date reviewed: August 2014