Gustatory sweating on the head, neck and arms, often occurs after cervico-thoracic sympathectomy. Haxton (1948) reported an incidence of 36 percent, the same as in the present series. It was thought that some information about regeneration in the cervical sympathetic might be revealed by investigation of this surgical curiosity.
Although sweating is the common gustatory response after cervical sympathectomy, other changes are experienced. Haxton (1948) described associated paresthesia and flushing, gooseflesh may occur (Herxheimer, 1958) and vaso-constriction is reported in this paper. These occur together or separately and occasionally sweating might be absent. The subject has been confused by comparison with post-parotidectomy gustatory sweating which has a different mechanism (Glaister et al.,1958; Bloor, 1958).
Sweating is produced by cholinergic sympathetic fibres. In normal individuals both vasocontriction and gooseflesh are adrenergic. This also holds in gustatory responses. Figure 2 shows blocking of sweating by atropine, whilst gooseflesh continues unchanged.
The tingling sensations were described as being unlike normal sensation, and likened to plucking out of hair. In one patient in was so unpleasant that she refused to take a test stimulus. Flushing usually occurs on the upper chest and neck, and is an erythema with sharp demarcation, not associated with a rise in skin temperature.
Of the patients, 29 were found to have gustatory responses, and 24 were studied in detail. Of 22 patients with sweating who could be studied, 11 had gooseflesh, 10 tingling, 6 flushing, and 4 vasoconstriction. Four patients, however, had no sweating and their gustator responses consisted of gooseflesh and tingling in one, tingling alone, and flushing in two. None of these four showed vasoconstriction.
The stimulus for testing used was usually Worcester sauce, but specificity of the response was sometimes great, and one patient reacted only to boiled sweets made by one particular firm.
http://brain.oxfordjournals.org/content/92/1/137.extract &
http://ang.sagepub.com/content/17/3/143.extract
The development of gustatory sweating after cervical sympathectomy can only be explained if one is to admit that the primary event of gustatory sweating is a degeneration of the cervical sympathetic neurons. The initial event is the loss of postganglionic sympathetic neurons and the resulting denervation of the corresponding facial sweat glands. Regeneration of parasympathetic fibers, within the degenerating sympathetic neurilemmal sheets, is a secondary event although it accounts for the observed symptoms.
Salivary gland disorders
Springer, 2007 -
Medical - 517 pages
In a series of 100 bilateral upper dorsal sympathectomies performed for palmar hyperhidrosis, gustatory sweating and other gustatory phenomena were reported by 68 of 93 patients (73%), followed up for an average of 11/2 years. These gustatory phenomena were quite different from physiologic gustatory sweating: a wide range of gustatory stimuli caused a variety of phenomena in varied locations. There was a negative correlation between the incidence of these phenomena and the occurrence of Horner's syndrome after sympathectomy. Analysis of our observations, and of clinical and experimental work of others, leads to the conclusion that gustatory phenomena after upper dorsal sympathectomy are the result of preganglionic sympathetic regeneration or collateral sprouting with aberrant synapses in the superior cervical ganglion.
http://archneur.ama-assn.org/cgi/content/abstract/34/10/619
