Many people with chronic hives learn to avoid the common triggers that make their condition worse. But what would you do if you were allergic to water? That’s a question that Tessa Hansen-Smith, 25, has to ask herself every day, as she contracts hives after any contact with water. Today, she’s raising awareness about one of the rarest kind of allergies known as aquagenic urticaria, a condition in which people break out in hives after they come into contact with water. After she told students in college at University of California, Davis, about her diagnosis, some would deliberately splash water or hurl ice cubes at her because they didn’t believe her, according to a recent report.