Neurologist Phillip A. Low, M.D., founded the autonomic nervous system testing laboratory at the Mayo Clinic about 30 years ago. He and his colleagues set standards for quantified evaluation of autonomic function, including the thermoregulatory sweat test (TST).

A 2006 study entitled "Thermoregulatory Sweat Testing in Patients With Erythromelalgia" (pdf) [WARNING: Graphic Medical Image] reached the conclusion that small-fiber neuropathy is prevalent in most patients with erythromelalgia; and Thermoregulatory Sweat Testing is a sensitive and useful marker of small-fiber neuropathy in these patients.

I believe I've had peripheral neuropathy for several years, and I've noticed in the last year especially that my skin would heat up in different places inexplicably but then never sweat, so I couldn't cool down easily. I still wake up every night feeling too hot. (The anomaly is that my core temp. is cold at 96.8F.)

It seems skin pressure triggers a nerve reaction. When I stand, my left foot feels hot. When I sit, the same type of thing. When I lie down on my side, it soon feels uncomfortably hot.

Sometimes my skin will feel hot (but it's actually cold; for example, if I touch it with my hand). Other times it is actually hot, but there's no sweat. It feels as if the heat gets trapped. My pillow (water) also gets extremely hot during sleep even when the RT is 18C, but there's never a drop of sweat.

Does anyone else have anything like this? Or have you ever got a Thermoregulatory Sweat Test?