There is a specific condition called Aquagenic Urticaria (AU), where someone can be allergic to water as water touches the skin. When water comes in contact with the skin, it can cause symptoms such as itchy skin, hives, or even swelling. There have only been about 50 reported cases in the whole world, so this disease is very rare. These reactions can spark when any type of water comes in contact with the skin, including rain, snow, swear, and even tears. However, these reactions usually do not happen when you drink water, because the water does not directly touch the skin, so no, someone can not be allergic to drinking water, everyone can drink water. The symptoms of Aquagenic Urticaria usually come within 30 minutes of being in contact with water, and can last anywhere from 30 minutes to 2 hours, and the symptoms will usually cure themselves, going away on their own. Unfortunately there is no cure for Aquagenic Urticaria, meaning people with this will have to go their whole life while being allergic to water, making it very hard to do a lot of things, including showering. However, there are oils and creams that you can apply to the body to combat this, making it possible to come in contact without water without having an allergic reaction.