Can shower or bath water cause rashes?

Water urticaria, or aquagenic urticaria, is a rare condition in which hives develop within 1 to 15 minutes after contact with water. The hives last for 10 to 120 minutes and do not seem to be caused by histamine release like the other physical hives. Most investigators believe that this condition is actually exquisite skin sensitivity to additives in the water such as chlorine.

How do you know if you or a loved on has it? Water urticaria is diagnosed by applying tap water and distilled water to the skin and observing the reaction. What is the treatment? Water urticaria is treated with a cream called capsaicin (Zostrix) that is applied to the irritated skin. This is the same treatment used for shingles. Antihistamines are of questionable benefit since histamine is not the causative factor in water urticaria.

Other Causes of Rashes.

Heat rash. Heat can bring urticaria out, or make it worse.

Chronic 'idiopathic' urticaria. By far the commonest form of urticaria, which lasts a long time. A puzzling name for a puzzling condition.

Cold Urticaria. If cold brings out your hives, take great care to avoid falling in the water, and see a specialist.

Pressure Urticaria. There are at least two completely different kinds of urticaria brought on by pressure on the skin.

Cholinergic urticaria. Tiny hives when you get hot. Sunlight can cause urticaria:

Solar urticaria. Hives caused only by direct sunlight, a rather rare condition. The much more common 'polymorphous light eruption' can be mislabeled as solar urticaria.

Vasculitic urticaria, urticarial vasculitis.

Contact urticaria. Hives from allergy to things touching the skin.

Urticaria caused by aspirin, and by food coloring and preservatives, and salicylates. The commonest discoverable cause of chronic urticaria, which you can do something about. The dietitian may make tablets unnecessary, but aspirin and some other painkillers could be dangerous.