What’s Behind Your Hives?

Those itchy bumps can be a real pain. Here’s what could be causing them.

Your skin goes through a lot. It’s there through every ray of sun, cut, bug bite and scrape. So, when it gets irritated, your skin can be pretty unhappy. If you’ve ever had an unexpected case of hives, you might wonder where they came from (and what to do to get relief).

What are hives?

“Hives, also called urticaria, are raised, itchy welts that develop on your skin,” says Mikael Horissian, MD, dermatologist at Geisinger.

They’re a reaction to your body releasing a chemical called histamine.

These bumps can range in size from a few millimeters (think a small pimple) to a few centimeters (the size of a quarter) or larger. Hives can be red, the color of your flesh or white.

They also come on suddenly and disappear quickly, usually within 24 hours.

Types of hives include:

Acute urticaria: The most common type of hives. This type is short-lived, typically lasting less than six weeks.
Chronic urticaria: Chronic hives last longer than six weeks. And they can keep returning for months or even years.

What causes hives?

Hives can be caused by different things like:

Allergic reaction

The most common cause of hives? Allergic reactions. Allergic reactions can be caused by:

Bug bites
Medications, especially antibiotics
Pollen and other seasonal allergy triggers

Stress

“Stress and anxiety can cause our bodies to release histamines, which triggers inflammation,” Dr. Horissian says. That inflammation can lead to a type of hives known as cholinergic urticaria.

Temperature changes

Rapid changes in your body temperature can cause you to break out in hives. This can happen from excessive cold or heat. They usually resolve on their own once your body temperature goes back to normal.

Infections

Having a virus can sometimes trigger hives. They don't always happen while you're sick, either. “Hives can appear during or after a viral illness,” says Dr. Horissian.

Other causes

Sometimes, the cause of hives is unknown. But some less common causes of hives include:

Sunlight
Exercise
Contact with water
Certain autoimmune conditions
Tight clothing or straps irritating the skin

Finding relief

When you have hives, the only thing you care about is getting relief. Depending on the type of hives you have, you may have the tools you need in your medicine cabinet. Your healthcare provider may recommend these things to help.

Antihistamines

Antihistamines work to reduce the occurrence of hives and reduce symptoms, like itching. They can relieve your symptoms. And they can stop the urge to scratch the area, preventing you from further irritating your skin.

Anti-itch creams

Like antihistamines, these creams work to lessen itchiness. Common types include calamine lotion or hydrocortisone. For more severe cases, your healthcare provider may prescribe a steroid cream.

Cold compresses

Applying a cold compress to hives can help reduce swelling and soothe your skin. Dr. Horissian recommends applying a cold washcloth or ice to the affected area for a few minutes.

Other ways to get relief include taking a cool shower or bath and wearing loose-fitting clothes.

Getting to the bottom of things

If hives are more severe or long-lasting, your healthcare provider may recommend a prescription medication. They may also order tests to look for the cause. And if they’re not sure of the reason for your hives, they can help you find the right treatment so you can feel your best.