Baseline water loss and cholinergic sweat stimulation in atopic dermatitis: a gravimetric measurement of local skin water loss.

The sweat gland function in atopic dermatitis (AD) and in respiratory atopy is a matter of controversy. We examined the baseline water loss and local sweating response in non-eczematous back skin of 146 young men: pure AD, AD with rhinitis/asthma, rhinitis/asthma alone, non-atopic dermatosis and non-atopic healthy. All AD subjects were further divided into the subgroups AD dry and AD normal skin. Following injections of saline and a high concentration of methacholine (5 x 10(4) mol/l) into separate sites the moisture losses were collected into closed pads over a period of 40 min. The baseline water loss was significantly increased (P less than 0.001) and median pure sweat loss was significantly decreased (P less than 0.01) in AD compared with nonatopic healthy individuals. These trends were accentuated in AD dry skin. Respiratory symptoms had no appreciable influence on results. A depressed sweating response occurred in 30% of AD subjects and 9% of non-AD subjects. An elevated baseline water loss value and a depressed sweat loss value coexisted in 22% of subjects with AD dry skin compared with 3% of the non-atopics.