Local sweat stimulation with the skin prick technique.

Intracutaneous injections of cholinergic agonists are usually employed for induction of local sweating. The possibility to apply a less painful skin prick technique as a sweat test was examined. Pricks were made on the forearm skin of 25 young men by puncturing the skin through drops of methacholine (MCH) and control saline solutions with lancets having a point length of 1 mm. The drops were kept on skin for 10 min and were then wiped off. Using an evaporimeter the measurements of water loss (WL) were started 5 min later and continued at 5 min intervals. Sweat loss (SL) was calculated from the difference of rates of evaporative WL recorded at the MCH and saline pricks. Ten, 1, 0.1, and 0.01% solutions of MCH elicited the following average peak evaporative sweat losses: 107.1, 77.5, 32.4 and 5.4 g m-2h-1. Both the degree and duration of the sweat responses were dependent on concentration. The prick technique is well tolerated and may serve for comparative studies of local sweating.