Teen's Water Allergy Treated Successfully with Daily Pill

Imagine dreading every shower, every rainstorm, every swim because water itself makes your skin break out in painful welts. That was reality for a Canadian teenager who discovered she had one of the world's rarest allergies.

The girl first noticed something was wrong about two years after she started menstruating. Within 20 minutes of bathing, showering, swimming in pools or ocean water, or getting caught in rain, raised bumps surrounded by red patches would appear on her skin. The welts would fade on their own after 30 to 60 minutes, but the cycle repeated every time water touched her.

Her doctors ran tests to rule out common allergens. She was allergic to dust, rabbits, and cats, but none of those explained the water reaction. Her blood work and urine tests came back normal, and she had no family history of unexplained hives.

To confirm their suspicion, doctors performed a provocation test. They placed a cloth soaked in room temperature water on her abdomen and waited. Within 20 minutes, the telltale welts appeared, confirming their diagnosis of aquagenic urticaria, a water allergy so rare that only 100 cases have ever been documented worldwide.

The condition typically appears at puberty and affects women more often than men, though researchers still don't understand what causes it. Diagnosing it is particularly tricky because hives can also be triggered by pressure, extreme temperatures, exercise, and countless other allergens.

The teen's mother had tried managing the symptoms with asthma medication, which helped moderately but didn't solve the problem. Doctors prescribed a daily dose of cetirizine, a common antihistamine that targets the root cause of allergic reactions.

The Bright Side

The simple solution worked remarkably well. Eight months after starting the medication, the teenager reported that her symptoms only returned if she missed a dose. By her 14-month follow-up appointment, she told doctors she could participate in all normal daily activities without any restrictions.

Her quality of life returned to normal as long as she took her daily pill. For someone living with such an unusual condition, that daily antihistamine represents freedom to shower without dread, swim without worry, and walk in the rain like everyone else.

This case shows that even the rarest medical mysteries can sometimes have straightforward solutions.