Chronic paroxysmal hemicrania. IX. On the mechanism of attack-related sweating.

In eight patients with chronic paroxysmal hemicrania (CPH), forehead sweating was measured after various provocation tests-body heating, exercise, and subcutaneous pilocarpine administration (0.1 mg/kg body weight). Evaporation was measured bilaterally on the forehead with an Evaporimeter (in g/m2/h). This was carried out in a thermo room under standardized conditions. There was no definite deficit in heat-induced or exercise-induced sweating on the symptomatic side of the forehead, contrary to findings in cluster headache. Neither did pilocarpine lead to any marked initial, temporary predominance of sweating on the symptomatic side, which has previously been found in cluster headache. In cluster headache there may be denervation supersensitivity of the sweat glands in the forehead of the symptomatic side. The present study does not therefore provide evidence for supersensitivity phenomena which could explain the homolateral forehead sweating increase seen during attacks in some CPH patients. The localized sweating increase in the forehead during attacks of CPH may possibly be a result of direct sympathetic stimulation.