Biopsy specimens have been obtained from the skin of 28 patients with proven or suspected hypothyroidism. Specific cytologic changes were found in the eccrine sweat glands in all patients who were under treatment for less than 4 months and in some patients who had been treated for a year or longer. Skin biopsy may provide a simple and useful method for the diagnosis of hypothyroidism, particularly when conventional tests are impracticable.
Means MA, Dobson RL. Cytological Changes in the Sweat Gland in Hypothyroidism. JAMA. 1963;186(2):113-115. doi:10.1001/jama.1963.03710020033007