A person with Aquagenic Urticaria is essentially allergic to water. It is an extremely rare condition with no cure.
After coming into contact with water - or blood, sweat and tears - the sufferer develops painful, itchy hives that spread over the affected area. These can last anywhere between 10 minutes to an hour-and-a-half and some sufferers have to lie down to let the pain subside.
There is no proven treatment, so the recommendation is to avoid all forms of water, keeping showers short and avoiding rain. Dermatologists say those with the condition can ease the burn of the hives with certain antihistamines.
More allergy information and advice here