Tests and diagnosis

By Mayo Clinic Staff

Your doctor is likely to suspect anhidrosis based on your signs and symptoms, a thorough medical history, and physical exam, but you may need certain tests to confirm the diagnosis. These include:

  • Axon reflex test. In a test called a quantitative sudomotor axon reflex test (QSART or QSWEAT), small electrodes placed on your forearm, leg and foot activate the nerves that supply your sweat glands. The volume of sweat produced by this stimulation is then measured. You may feel a mild tingling or slight burning sensation during the test.
  • Silastic sweat imprint. This test measures the size distribution of perspiration by taking an imprint of drops of sweat in a rubbery material (Silastic). As in the axon reflex test, small electrodes are used on the hand and foot to stimulate sweating.
  • Thermoregulatory sweat test. During this test, you're coated with a powder that changes color when and where you sweat. You then enter a chamber that causes your body temperature to increase to a level that makes most people perspire. Digital photos document the results, and the whole body surface can be tested at once.
  • Skin biopsy. In some cases, your doctor might request a biopsy of the area suspected of anhidrosis. For this test, skin cells and sometimes sweat glands are removed for examination under a microscope.

Sometimes the cause of anhidrosis or hypohidrosis can't be found.

Feb. 15, 2012