Sympathetic skin response in patients with systemic sclerosis and rheumatoid arthritis

Background: Sympathetic skin response (SSR) is a technique to assess the sympathetic cholinergic pathways. Sympathetic dysfunction may participate in the development of pain, which is the major complaint in patients with systemic sclerosis (SSc) and rheumatoid arthritis (RA). Objectives: In this study, we aimed to assess the autonomic dysfunction in patients with (SSc) and (RA) using SSR as a simple neurophysiologic test. Methods: Palmar SSR to median nerve electrical stimulation was recorded in 21 patients with SSc, 39 patients with RA, and in 60 healthy age and sex-matched control subjects. Results: Palmar SSR to median nerve stimulation (of SSc patients and RA patients) shows significantly delayed latency and reduced amplitude in comparison to the control group. SSR of SSc patients has significantly delayed latency and reduced amplitude when compared to RA patients. Moreover, six SSc patients have delayed SSR in spite of the absence of manifestations of polyneuropathy. Conclusions: Patients with SSc and RA have features of autonomic dysfunction with more affection of SSc patients.