A New Method for Scoring Active Sweat Glands

Abstract

Two different and interrelated steps are involved in the assessment of active sweat glands: stimulation of sweating and its subsequent recording and quantification.Sweat activation has been promoted by simple thermal stimulation, by intradermal injection of drugs such as methylcholine, 1 and by dermal introduction of such drugs using iontophoresis. 2,3 Gibson and Cooke's device for iontophoresis, one of the most employed devices, 2 provides DC current and uses large lead electrodes lined with porous material. The positive pole is dampened with 2% pilocarpine hydrochloride, and the negative one with 0.9% NaCl solution.In order to visualize sweat glands, 2 methods have been used, ie, the starch-iodine test 1,4 and a method that allows permanent recording of sweat drops on silicone. 5 The latter method consists of stimulating sweat production, drying out the skin, and then applying a thin layer of liquid silicone to it. Prior to utilization, the silicone is mixed with a catalyzer that polymerizes and solidifies the material in about 90 seconds. The solid silicone is then manually removed, and sweat drops are counted by prints left on the material.With respect to recording sweating activity, the methods reported in literature are limited to what was available in 1972, as reviewed in a study by Harris et al 5 and reiterated in the recent Rook's Textbook of Dermatology (2004), 6 in which is stated "…silicone impression techniques are probably the most reliable…".We introduce a new dynamic operational method that includes 3 devices: 1) a small battery-powered iontophoretic apparatus to stimulate sweating, 2) a digital photo or video camera to record sequential digital photographs of sweat production, and 3) a computer loaded with digital image-processing software to quantitate the sweat drop production.