Why have a neurodiagnostic skin biopsy?

Skin biopsies have proved useful in diagnosing various small-fiber sensory neuropathies. Most patients with these syndromes will have frequent pain, usually starting in the feet, and sometimes spreading in time to involve other parts of the body. Other neurologic diseases can also cause skin abnormalities.

Who is not a good candidate for a neurodiagnostic skin biopsy?

If a person’s neuropathy symptoms involve only the nerves that travel to muscles, there are better tests for diagnosing neuropathy. Neurodiagnostic skin biopsy can only be performed on relatively normal skin, so patients with skin abnormalities on both lower legs, such as widespread scars or rashes, may not be appropriate for referral. Patients on blood-thinners such as warfarin (Coumadin) or heparin cannot be biopsied without making special arrangements. However, patients who use aspirin daily do not run any extra risk of bleeding. Patients allergic to lidocaine or other local anesthetics cannot be biopsied without making special arrangements. Patients with allergies to plastic or latex must inform the staff so that the appropriate precautions can be taken.

What will happen during the procedure?

Most patients with suspected sensory neuropathy will be biopsied at a standard location, above the ankle on one leg. Your physician might arrange for additional or alternative sites for biopsy, depending on your condition. The procedure will be discussed with you and the risks and benefits explained. You will be asked to sign informed consent giving permission to proceed. Biopsies are performed in the MGH Neurology Clinic by Ms. Dipu Patel, a Physician's Assistant. The biopsy site will be cleaned and a small amount of local anesthetic injected under the skin at the site to numb it. One or more small (3 mm diameter) full-thickness skin biopsies will be removed from the numbed skin using a sterile punch. Usually, 2 biopsies are removed from the same area, and sent to different labs for testing. The biopsy site is covered with a sterile plastic bandage, and the patient can leave immediately.

Is any special care needed after the biopsy?

A gauze pad is left over the plastic bandage for the first day. The gauze can be removed after 1 day; the plastic bandage can remain in place for 1–2 weeks. No special care is needed, and our only recommendation is to avoid hot tubs, since they can loosen the bandage and allow entry of germs from others. Routine showering, bathing, and swimming are fine. When the plastic bandage is removed or falls off, the area can be covered with a regular adhesive bandage strip if desired. A small pink dot will be visible where each skin punch was removed; these will fade over the coming months and, in most patients, blend into the skin.

What are the risks of neurodiagnostic skin biopsy?

Neurodiagnostic skin biopsy was developed precisely to avoid the greater risks and costs of sural nerve biopsy. The technique has been used on thousands of patients worldwide, with no known serious complications. The only possible complications are infection, bleeding, or allergy to latex or local anesthetic.