Pilocarpine-induced cholinergic sweat secretion compared with emotional sweat secretion in atopic dermatitis

We studied pilocarpine-induced cholinergic sweating, emotional sweating and sympathetic reflex sweating in atopic dermatitis (AD) patients. Secreted sweat was measured both with equipment that continuously records sweat rate and with a filter paper method that measures sweat weight absorbed. Comparison of the two methods revealed that the filter paper method underestimated the sweat secretion in AD patients. While AD patients showed no significant abnormalities in emotional sweating and sympathetic reflex sweating, the duration of pilocarpine-induced sweating was prolonged. The time from the maximal sweat rate until the sweat rate fell to half of the maximal rate was significantly longer in AD patients than in control subjects. In contrast, the time from the beginning of sweat secretion until the maximal sweat rate was not significantly different between AD patients and control subjects. There was no significant difference between AD patients and control subjects in sweat volume secreted in 20 min after pilocarpine iontophoresis. In AD patients, the total sweat volume secreted after pilocarpine iontophoresis was greater than in control subjects, although not significantly. These results suggest that the system of deactivation of pilocarpine-induced sweat secretion is impaired in AD patients whereas the activation system is not altered.