Thermoregulatory sweat testing in patients with erythromelalgia.
OBJECTIVE
To examine the results of thermoregulatory sweat testing in patients with erythromelalgia and to compare them with the results of other neurophysiologic tests of small-fiber nerve function.


METHODS
Retrospective study.


METHODS
Tertiary referral center.


METHODS
Thirty-two consecutive patients with erythromelalgia who had thermoregulatory sweat testing in addition to vascular and nerve testing.


METHODS
The following information was abstracted for each patient: demographics, clinical presentation, and results of thermoregulatory sweat testing, vascular (noninvasive) testing, and nerve testing (electromyography and autonomic reflex screen, including quantitative sudomotor axon reflex test).


METHODS
Results of thermoregulatory sweat testing to evaluate small-fiber neuropathy, compared with other tools used to estimate small-fiber neuropathy.


RESULTS
Thermoregulatory sweat testing results were abnormal in 28 (88%) of 32 patients, and quantitative sudomotor axon reflex test results were abnormal in 22 patients (69%). Abnormalities noted on thermoregulatory sweat testing varied from local hypohidrosis or anhidrosis to global anhidrosis. Global or almost-global anhidrosis was present in 8 patients (25%); in 19 patients (59%) the anhidrosis was distal, and 1 other patient (3%) had a less specific pattern of anhidrosis (multifocal or regional). The area of anhidrosis generally corresponded to the area that was symptomatic of the erythromelalgia.


CONCLUSIONS
Small-fiber neuropathy is prevalent in most patients with erythromelalgia. Thermoregulatory sweat testing is a sensitive and useful marker of small-fiber neuropathy in these patients.
Davis
Mark D P
MD
Department of Dermatology, Mayo Clinic, Rochester, MN 55905, USA. davis.mark2@mayo.edu
Genebriera
Joseph
J
Sandroni
Paola
P
Fealey
Robert D
RD
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001341:Autonomic Nervous System / Q000503:physiopathology; D001783:Blood Flow Velocity; D003937:Diagnosis, Differential; D004576:Electromyography; D004916:Erythromelalgia / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012867:Skin / Q000098:blood supply / Q000294:innervation; D013546:Sweating / Q000502:physiology*; D013817:Thermography / Q000379:methods*