Q. I was posted at a hill station about 14 years back. After four years i.e. 10 years ago, I started getting a burning sensation after taking a bath. After a years treatment at Dehradun and two years treatment at AIIMS, New Delhi, I left the medicine because they did not provide any relief. Now I have come to the conclusion that I am suffering with allergy from high humidity because after taking a bath for about 20-30 minutes I feel my body burns. After a rainfall, I feel the burning sensation again for quite some time, while in other seasons, the burning is less. When I go to the plains like Delhi, the burning is less after a bath but due to sweat, I feel sensation in my body like something is running on my body. Am I right to conclude that it is allergy to humidity? If yes, what is the solution?
I would have loved to know what your doctors at Dehradun and AIIMS had diagnosed. From your history I can make only a probable diagnosis of Cholinergic urticaria (after sweating), Water (aquagenic) urticaria, or aquagenic pruritus (itching). Aquagenic urticaria is a rare form of physical urticaria in which contact with any source of water (for example, sea or tap water) evokes hives. Aquagenic urticaria is a rare form of physical urticaria in which contact, the physical form of urticaria described in this question could be cholinergic urticaria. This occurs in approximately 15% of people at some time during their lives. It is most common in teenagers and young adults. It carries a very good prognosis for eventual improvement. About half of the patients who experience this have other allergic illnesses. There are characteristically itchy, small, red papules that occur when heat stimulus is applied to the skin. It is caused by activation of cholinergic sympathetic intervention to the sweat glands and it often subsides in minutes after the patient cools. The occasional patient may also have chest symptoms associated with this condition. It responds well to a medication called hydroxyzine, which is an antihistamine.
Aquagenic urticaria is a rare form of physical urticaria in which contact with any source of water (for example, sea or tap water) causes hives. It 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. Most investigators believe that this condition is actually exquisite skin sensitivity to additives in the water such as chlorine. It has to be differentiated from. Aquagenic pruritus(itch), in which contact with water induces itching without skin lesions.
Water urticaria is diagnosed by applying tap water and distilled water to the skin and observing the reaction.
Local symptoms: Raised, itchy wheals with surrounding redness, especially on upper body
Special features: Elevated blood histamine sometimes reported
Diagnostic test: 35 degree C water compress on upper body skin for 30 minutes
Avoid swimming, exercises causing sweating (a good doctor needs to check whether it is cholinergic urticaria)take bath rapidly and dry quickly.
Water urticaria is treated with a cream called capsaicin that is applied to the irritated skin. Antihistamines are of questionable benefit since histamine is not the causative factor in water urticaria.