Sweat studies under conditions of moderate heat stress in two patients with the Nägeli-Franceschetti-Jadassohn syndrome.

The sweating response of 2 patients with the Nägeli-Franceschetti-Jadassohn syndrome was measured by direct calorimetry. During the experiment, under conditions of moderate heat stress, the 2 patients felt comfortable and showed a normal thermoregulatory response. This tended to corroborate the patients' history which did not reveal a clear-cut heat intolerance. However, the starch-iodine test on the right flexor forearm revealed a marked reduction in activated sweat gland density while the patients were still under experimental conditions. Probably this was not the only region with a reduced number of functioning glands. Still, the patients' overall performance through the experiment indicated that their total number of functioning glands was able to produce a sweat output sufficient to prevent disturbances in thermoregulation. To our knowledge, this is the first study of the thermoregulatory capacity of patients suffering from a hereditary dermatosis in which hypohidrosis is part of the clinical picture.