What is a skin biopsy, and why is it done?
A skin biopsy is an easy and minimally invasive procedure that lets doctors examine the small sensory nerves in the skin. These nerves pass on information about pain and temperature. These types of nerves are often involved in certain kinds of peripheral nerve damage (neuropathies). The test lets doctors find the nerves and see how many of them there are and if they are healthy. In general, when the nerves are damaged, a number of nerves shows up as abnormal under a microscope.
How is a skin biopsy done?
A skin biopsy is a very simple outpatient procedure that takes about 10 to 15 minutes. This type of skin biopsy that examines nerves is typically done at three places on the leg: above the outer ankle, above the outer knee and the outer thigh.
- First, the areas are thoroughly cleaned with an antiseptic solution.
- A small injection of a local anesthetic (lidocaine) is used to numb the area where the biopsy will be taken. This may feel like a bee sting and only lasts for a few seconds. The skin is then checked for numbness.
- An instrument called a biopsy punch is used to remove a small sample of skin.
- Lastly, bandage dressings are used to cover the biopsy sites. Generally, the skin heals easily within one to two weeks without the need for stitches. The risk of bleeding or infection is extremely low.
The biopsy itself does not hurt, but getting the shot of local anesthetic before the biopsy usually causes a mild stinging sensation lasting a few seconds. After the biopsy, the skin heals rapidly within a few days and the healing site is almost never uncomfortable or painful.
What to do after a skin biopsy?
- Keep the dressings on the biopsy sites for 24 hours. After 24 hours, you may shower with the dressings on, then remove. Cover the biopsy sites with an adhesive bandage daily until a scab forms, then leave the areas open to the air. Do not remove the scabs that form.
- You may take showers, but please do not take tub baths, go in hot tubs, or swim for 7 days after the procedure.
- If bleeding occurs, apply firm pressure for 2 minutes using a clean piece of gauze.
- Initial mild redness may be present around the skin biopsy sites. If an area gets red, you may use Bacitracin or Polysporin® (Bacitracin and Polymyxin B) on the wounds as needed.
Results and Follow-Up
What should I look for at the biopsy site?
Before the biopsy, you will get detailed instructions about how to care for the healing biopsy site. It generally takes about a week for the biopsy to heal over and seal. The redness of the biopsy site will fade gradually over a few weeks or months. The doctor who referred you will get the results.