Water
In 2016, the BBC detailed the tragic story of Rachel Warwick, a woman unable to even sweat without developing red welts on her skin. Warwick is one of the few people in the world known to have something called aquagenic urticaria (urticaria being the medical term for hives). Though her body doesn’t overreact to the water stored inside her cells, skin contact with any outside source of water—no matter the temperature or how distilled it is—can cause an intensely painful and itchy sensation that lasts for hours. Scientists don’t know much about why or how the rare condition happens, though it is known to affect women more than men, and symptoms tend to emerge in puberty.
