Aquagenic urticaria, also known as water allergy and water urticaria, is a rare form of physical urticaria in which hives develop on the skin after contact with water, regardless of its temperature. The condition typically results from contact with water of any type, temperature or additive. Signs and symptoms
The main symptom of aquagenic urticaria is the development of physical hives, which may or may not itch. Itching after contact with water, without the development of physical hives, is known as aquagenic pruritus. Aquadynia is a condition in which pain occurs after contact with water.In severe cases, drinking water can result in swelling of the oral cavity , swelling of the throat  and in extreme cases, anaphylaxis. The hives associated with aquagenic urticaria are typically small (approximately 1–3 mm), red- or skin-colored welts (called wheals) with clearly defined edges. It most commonly develops on the neck, upper trunk and arms, although it can occur anywhere on the body. Once the water source is removed, the rash generally fades within 30 to 60 minutes.Water in all forms, such as tap or sea water, swimming pool water, sweat, tears, and saliva can induce the lesions. Cause
The cause of aquagenic urticaria is not fully understood; however, several mechanisms have been proposed. Interaction between water and a component in or on the skin or sebum has been suggested. This theory suggests that a substance is formed by this interaction, the absorption of which causes perifollicular mast cell degranulation with release of histamine.
Sulfhydryl group-containing drugs should be avoided and steroids can be used in resistant cases. == References ==