A case of gustatory sweating.

Profuse facial sweating on eating is a rare phenomenon of interest not only as a clinical problem but also as a means of elucidating the complex mechanism of the nervous and hormonal control of perspiration. Of the cases described hitherto all except one have occurred as a result of sympathetic paralysis particularly in the distribution of the auriculo-temporal nerve. The present case is unusual in having no such predisposing cause and in presenting some unusual features on investigation. The usual story is that an injury to the sympathetic supply to a part of the face is followed after an interval of anything from a few days to several months by sweating, of varying degree, on eating. Investigation confirms the deficient sympathetic supply and shows that certain drugs like acetylcholine and pilocarpine which normally cause sweating on injection produce an excessive response. The one case in which no sympathetic paralysis occurred was a patient with syringomyelia (Wilson, 1936). A variety of explanations has been offered for the phenomenon of gustatory sweating. The sensitivity of the sweat glands to acetylcholine suggested that sweating might be due to a diffusion of this substance from the cholinergic nerve endings during reflex salivation (List and Peet, 1938). On the other hand it was suggested that since section of the sympathetic nerves had taken place there might have been abberrant regeneration in which other cholinergic fibres, say salivary fibres, came to supply sweat glands so that there would be a sweating response to any stimulus to salivation (Ford, 1933). Yet another suggestion was that there might be a double innervation to the sweat glands of the face, since sweating, which could be inhibited by peripheral nerve block, was seen to occur in an area where the sympathetic nerves were known to have degenerated (Wilson, 1936; Guttmann, 1931). Unfortunately none of these explanations can be applied to the present case in which, as will be shown, sweating appears to occur in response to stimulation through normal channels.