Sweating response to moderate thermal stress in atopic dermatitis

The local sweating response to thermal stress (mean ambient temperature 33 degrees C) was assessed under resting conditions on the non-eczematous back skin of 26 young men with atopic dermatitis (AD) and in 22 non-atopic controls with other dermatoses. The baseline (transepidermal) water loss was separately determined at room temperature (mean 23.6 degrees C) to calculate the pure sweat loss. A gravimetric collecting method was used for the measurements at 40, 60 and 80 min. In the heated room the sweat loss in AD patients was significantly lower at all time intervals. The cumulative sweat loss was 50-60% lower in AD patients than in the controls (P less than 0.02). Subjects with dry AD skin had a lower sweat loss than subjects with normal-looking skin. Compared with controls the sweat loss in AD patients was lowest at 40 min, suggesting a retarded sweating response. Half of the patients with AD and half of the controls had active participation in sports, and showed a greater sweat loss compared to the non-sporting subjects in the same group.