Water allergies real, but rare

Aquagenic urticaria causes hives and affects daily life

Yes, it's true. There is a rare condition called aquagenic urticaria that causes people to have an allergic skin reaction to water. Imagine getting hives and bumps as often as several times a day when you come into contact with water — for example, taking a shower or bath. It can interfere with many aspects of work, social and daily life.

“We just don't know,” says Dr. Benjamin Barankin, dermatologist, medical director and founder of Toronto Dermatology Centre, when asked what causes a water allergy. “The water seems to cause a histamine release from mast cells in the skin that leads to hives, which is consistent with an allergy. Mast cells are immune cells in connective tissue throughout the body. They regulate immune responses, blood vessel formation and dilation, and overall balance.”

Barankin, who has served on the executive of the Canadian Dermatology Association, says that no one has a full understanding of the factors that could put you at risk.

WHAT DOES A WATER ALLERGY LOOK LIKE?

When people with the condition come into skin contact with water, they develop itchy hives — usually on the neck, upper torso and arms, although it can happen anywhere on the body. The hives are made up of red-coloured raised bumps on the skin called wheals. Even contact with your sweat and tears can trigger a reaction.

“The rash can spread to affect areas that didn't touch water,” says Barankin. “The wheals usually disappear within 30 to 120 minutes after stopping contact with water. People feel itching, burning and prickling.”

In rare instances, symptoms of wheezing and shortness of breath can occur.

LACK OF SCIENTIFIC STUDY

Boston University School of Medicine researchers reviewed the diagnostic and management challenges of the condition in the Journal of Asthma and Allergy, pointing to the lack of scientific study and the low numbers of people with the condition — estimated at about 50 cases in 2016. The findings showed that while there have been child-onset patients, aquagenic urticaria is more common in younger women and those with a family history. Symptoms can dissipate with aging.

WHAT KIND OF DOCTOR TREATS URTICARIA?

Barankin says urticaria is more commonly treated by an allergist, but it is seen in dermatology clinics periodically because of reactions to infections and medications.

CAN SOMEONE ALLERGIC TO WATER DRINK IT?

People with aquagenic urticaria can safely consume water. However, if any water comes into contact with the skin, there will likely be a reaction.

HOW IS IT TREATED?

The best treatment is to eliminate contact with water when possible, which can be tricky. Antihistamines can provide relief and are most effective if they're taken on a regular schedule to prevent hives from forming.

“Non-sedating antihistamines are very safe and can be taken daily as a preventive, or one hour before exposure to water,” says Barankin.

For more information and help, see a dermatologist or allergist who can provide treatment and care.