A skin biopsy is used to diagnose or help treat skin conditions and diseases, including:

• Actinic keratosis.
• Blistering skin disorders.
• Skin cancer.
• Skin tags.
• Irregular moles or other growths.

A skin biopsy is usually safe. But unwanted results can occur, including:

• Bleeding.
• Bruising.
• Scarring.
• Infection.
• An allergic reaction.

Before the skin biopsy, tell your health care provider if you:

• Have had reactions to creams or gels applied to your skin.
• Have had reactions to tape.
• Have been diagnosed with a bleeding disorder.
• Have had serious bleeding after a medical procedure.
• Are taking blood-thinning medicine. Examples include aspirin, aspiring-containing medicine, warfarin (Jantoven) and heparin.
• Are taking supplements or homeopathic medicine. At times these can cause bleeding when taken with other medicine.
• Have had skin infections.

Depending on the location of the skin biopsy, you may be asked to undress and change into a clean gown. The skin to be biopsied is cleaned and marked to outline the site.

You then receive medicine to numb the biopsy site. This is called a local anesthetic. It's usually given by injection with a thin needle. The numbing medicine can cause a burning feeling in the skin for a few seconds. After that, you shouldn't feel any pain during the skin biopsy. To make sure the numbing medicine is working, your health care provider may prick your skin with a needle and ask you if you feel anything.

A skin biopsy typically takes about 15 minutes, including:

• Preparing the skin.
• Removing the tissue.
• Closing or bandaging the wound.
• Getting tips for at-home wound care.

During the skin biopsy

What you can expect during your skin biopsy depends on the type of biopsy you'll undergo.

• For a shave biopsy, a razor-like tool is used to scrape the tissue. The depth of the cut varies. A shave biopsy causes bleeding. Pressure and a medicine applied to the skin are used to stop the bleeding.
• For a punch biopsy or an excisional biopsy, a cutting tool collects a sample from the deeper skin layers. Stitches may be needed to close the wound. A bandage is placed over the wound to protect it and prevent bleeding.

After the skin biopsy

Your health care provider may instruct you to keep the bandage over the biopsy site until the next day. Sometimes the biopsy site bleeds after you leave the clinic. This is more likely in people taking blood-thinning medicine. If this occurs, apply direct pressure to the wound for 20 minutes, then look at it. If bleeding continues, apply pressure for another 20 minutes. If bleeding still continues after that, contact your health care provider.

All biopsies leave scars. They tend to fade with time. The scar's permanent color will be set 1 to 2 years after the biopsy.

Some people develop a thick, raised scar. This type of scar, also called a keloid scar, is more common in people with brown or Black skin. The risk of a keloid scar is also higher when a biopsy is done on the neck, back or chest.

Avoid bumping the area or doing activities that stretch the skin. Stretching the skin could lead to bleeding or a bigger scar. Don't soak in a bathtub, swimming pool or hot tub until your health care provider says it's OK — usually about seven days after the procedure.

Healing can take several weeks. Wounds on the legs and feet tend to heal slower than those on other areas of the body.

Clean the biopsy site two times a day unless it's on your scalp. Scalp wounds can be cleaned once a day. Follow these steps:

• Wash your hands with soap and water before touching the biopsy site.
• Wash the biopsy site with soap and water. If the biopsy site is on your scalp, use shampoo.
• Rinse well and pat dry with a clean towel.
• Apply a thin layer of petroleum jelly. Use a new container of petroleum jelly the first time you do wound care. Use a new cotton swab each time you apply the product.
• Cover the site with a bandage (Band-Aid, Curad, others) for 2 to 3 days after the procedure.

If you have stitches, continue wound care until they're removed. If you don't have stitches, take these wound care steps until the skin is healed.

If your wound is sore, ask your health care provider if you can apply ice wrapped in a thin towel.

Your biopsy sample is sent to the lab to be tested for signs of disease. Ask your health care provider when you may get results. It may take a few days or even months, depending on the type of biopsy, the tests being done and the lab's procedures.

Your health care provider may ask that you schedule an appointment to discuss the results. You might want to bring someone you trust to this appointment. Having someone with you may help with hearing and understanding the discussion.

List questions that you want to ask your health care provider, such as:

• Based on the results, what are my next steps?
• What kind of follow-up, if any, should I expect?
• Is there anything that might have affected or altered the test results?
• Will I need to repeat the test?
• If the skin biopsy showed skin cancer, was all of the cancer removed?
• Will I need more treatment?