Alexandra Allen was 12 when she first had an allergic reaction to water. After spending a long vacation day swimming and splashing around in a pool, Allen found herself covered in angry red hives. Though it was clear she was allergic to something, initially no one suspected it could be water.

But from that point on, Allen continued to break out at the touch of water—and her outbreaks started to increase in intensity. Doctors assumed she was sensitive to chemicals in impure water and repeatedly prescribed antihistamines to combat the allergy—but the antihistamines didn’t help. Finally, after reading a list of strange diseases on the Internet, Allen diagnosed herself. She printed the article and brought it to her allergist, whose initial skepticism turned to shock when a simple test—pressing a water-soaked rag to Allen’s arm—came out positive. 

In an interview with New York Magazine, Allen, now 18 and in college, described what it feels like to be allergic to water. “Technically, it’s a skin disease, not an allergy,” she explained. “Everyone produces oils that soften their skin, but the oils I produce become toxic when they meet water—and that’s the part that’s a mystery to doctors.”

“I describe it as like the top layer of your skin getting sandpapered off—you feel very raw,” she said. 

The illness, which was first observed in 1963, is incredibly rare: fewer than 100 cases have ever been recorded. As a result, few trends or risk factors have been identified, though so far it’s more common in women, and usually begins during puberty. Its technical name is aquagenic urticaria. 

Allen has learned to live with the disease, though she admits it’s frustrating: she can’t go out in the rain, and always carries a jacket to cover up her frequent outbreaks of hives. But she still finds occasional humor in her situation: “I was recently at this party where somebody had water balloons and squirt guns, and it was this hilarious moment where everyone around me had this look of terror realizing that they had to protect me from water,” she said. “I feel like that’s a quintessential moment in my life—I need an entourage to protect me from squirt guns.” 

Read the full interview at New York Magazine.