Aquagenic urticaria is a rare form of urticaria, a type of hives that causes a rash to appear after you touch water. It’s a form of physical hives and is associated with itching and burning.

Aquagenic hives is thought to be a water allergy. However, research is limited.

According to a 2011 report, there are fewer than 100 cases of aquagenic urticaria reported in medical literature.

Hives from this condition can be triggered from many water sources, including:

  • rain
  • snow
  • sweat
  • tears

Researchers are still working to determine the exact cause of aquagenic urticaria. Some speculate it’s the chemical additives in water, like chlorine, that cause the reaction, rather than contact with water itself.

The allergy-like symptoms you may experience from this rash are due to the release of histamine.

When you have an allergic reaction, your immune system releases histamines as a response to fight off the harmful substance. These histamines can trigger allergy-like symptoms depending on what part of the body is affected.

Aquagenic hives is a rare condition that can cause an itchy, painful rash. This rash commonly appears on the neck, arms, and chest, though hives can appear anywhere on the body.

Within minutes of being exposed to water, people with this condition can experience:

In more severe cases, drinking water can cause you to experience symptoms including:

When you dry your body, symptoms should begin to fade within 30 to 60 minutes.

To diagnose aquagenic urticaria, your doctor will conduct a physical exam to observe your symptoms. They’ll also review your medical history, and may also perform a water challenge test.

During this test, your doctor will apply a water compress of 95°F (35°C) to your upper body. This is done to trigger a reaction. Symptoms should begin within 15 minutes.

Your doctor will record your reaction to the water challenge test and compare it to symptoms of aquagenic pruritus. Aquagenic pruritus causes itching and irritation, but doesn’t cause hives or reddening.

There’s no cure for aquagenic urticaria. However, there are treatment options available to alleviate symptoms.

Antihistamines are medications used to treat allergy-like symptoms. Your doctor may recommend you take a prescription antihistamine to calm your hives after coming into contact with water.

If you have a severe case of aquagenic urticaria and can’t breathe, you may need to use an EpiPen. EpiPens contain epinephrine, also known as adrenaline. They’re only used as an emergency alternative for severe allergic reactions. EpiPens increase blood pressure to reduce swelling and hives. They help the lungs function when they’re constricted.

Once you receive a diagnosis of aquagenic urticaria from your doctor, you should try to avoid touching water.

This isn’t always possible. Try to restrict your contact with water as much as you can. This includes taking brief, infrequent showers, wearing moisture-wicking clothes, and being mindful of the weather.

You may also want to change your diet to avoid foods that have a high water content.