A New Wrinkle in Diagnosing Small-Fiber Neuropathy

New findings, if confirmed, suggest that the inexpensive, readily available test of stimulated skin wrinkling may be useful in screening for SFN.

Confirming a diagnosis of small-fiber neuropathy (SFN) usually requires specialized testing that may not be readily available. These authors sought to determine whether the simple test of inducing skin wrinkling could identify small-fiber dysfunction in 21 patients with idiopathic SFN accompanied by foot and hand dysesthesias. The researchers exposed the participants to two conditions to induce skin wrinkling on the fingertips: 40°C saltwater and a eutectic mixture of local anesthetics (EMLA). They also underwent sympathetic skin response (SSR) testing of four limbs and punch biopsy of glabrous hypothenar skin for measurement of intraepidermal nerve fiber density.

As expected, the SSR was poorly sensitive (43%) for SFN. The sensitivities of …

Reviewing Author

David Lacomis, MD