A skin biopsy is a procedure in which a dermatologist cuts and removes a small sample of skin to have it tested. This sample may help your dermatologist diagnose diseases such as skin cancer, rashes, infection, or other skin disorders. Done under local anesthesia in the office, the procedure is quick and relatively painless.
First, the skin is sanitized with alcohol or another antiseptic. Then a small amount of numbing medicine is injected into the skin surrounding the spot to be biopsied. At most, you’ll feel a minor burning sensation for 10 seconds as the anesthesia is injected. Then, the biopsy procedure will be performed.
There are several types of skin biopsies including:
Shave biopsy: The top layer of skin is shaved off with a small blade. This procedure is generally used to diagnose nonmelanoma skin conditions such as actinic keratosis and basal and squamous cell carcinoma. A deeper shave biopsy called a "scoop" or "saucer" shave biopsy is sometimes used to rule out a melanoma. Stitches are not required and bleeding is minimal.
Punch biopsy: The doctor uses a tool that looks like a tiny round cookie cutter to remove a deeper layer of the skin. If a large sample is taken, one or two stitches may be needed.
Incisional vs. excisional biopsy: An incisional biopsy involves removing a small sample of a lesion with a scalpel. An excisional biopsy removes the entire lesion with a scalpel. Stitches are used to close the wound.
During these procedures, there is usually a small amount of bleeding. This is stopped using cautery, a small electrical current that closes the wound or sometimes aluminum chloride is applied to the wound to stop bleeding. Then a layer of Vaseline is applied and a bandage. Some biopsies require sutures but most do not. Healing occurs in 1 to 2 weeks.
Biopsies are mainly performed to determine whether a lesion is cancerous, precancerous, or benign. By examining the biopsied specimen under a microscope and using special stains, the dermatopathologist can give a more exact diagnosis than is possible with physical examination alone.
What to Expect After a Skin Biopsy
After the skin biopsy is done you may have some soreness around the biopsied site for a few days. Tylenol is usually sufficient to relieve any discomfort. If you had stitches after the procedure, keep the area as clean and as dry as possible. Your doctor will tell you when the stitches should be removed. You should expect a small scar from the biopsy.
What Is Done With a Skin Biopsy Sample?
The tissue is processed, and a dermatopathologist examines the skin biopsy sample under a microscope to determine if there is any disease. The results usually come back within one to two weeks.
When Should I Call the Doctor After a Skin Biopsy?
Call your doctor if you have bleeding that can't be stopped by applying pressure or any signs of infection such as redness, warmth, pus, or red streaks. Also call if you have any questions or concerns after a skin biopsy.