Patterns of sympathetic skin response in palmar hyperhidrosis.

Sympathetic skin responses (SSRs) were studied in 44 patients with palmar hyperhidrosis. The mean age was 19 +/- 4 years and the mean age of onset 9.1 +/- 3.6 years. Palmar SSRs were evoked by median nerve stimulation and by magnetic stimulation of the neck. Four types of SSR were identified: normal response, small-amplitude response, multiphasic response and absent response. Four palmar conditions were also identified: warm-wet in 26 patients, warm-dry in seven, cold-wet in seven, and cold-dry in four. Normal SSRs were present in about 25% of patients and absent SSRs in another 25%. The other two types of SSR were evenly distributed among patients, except those with cold-dry palms, who only had absent responses. There was no apparent difference between centrally and peripherally activated SSRs. It is concluded that skin temperature and moisture of the palms play an important role in producing different types of SSR in palmar hyperhidrosis.