What is a skin biopsy?

Skin biopsy

skin biopsy is a procedure in which a small sample of skin is removed to examine it. The skin sample is examined under a microscope to detect skin cancer, skin infections or skin diseases, such as psoriasis.

There are three main ways to do a skin biopsy:

  • A punch biopsy, which uses a special circular tool to take the sample
  • An exfoliative biopsy, which takes the sample with a razor blade
  • An excisional biopsy, which takes the sample with a small knife called a scalpel

The type of biopsy that is obtained depends on the place and size of the abnormal part of the skin, known as a skin lesion. Most skin biopsies can be done in the doctor's office or and do not require hospitalization.

Other names: punch biopsy, scrap biopsy, excisional biopsy, skin cancer biopsy, basal cell biopsy, squamous cell biopsy, melanoma biopsy



For what do you use it?

A skin biopsy is used to diagnose a variety of skin conditions, including:

  • Skin diseases, such as psoriasis and eczema
  • Bacterial or fungal infections of the skin
  • Skin cancer. A biopsy can confirm if a mole or other suspicious growth is cancerous or not.

Skin cancer is the most common type of cancer in the United States. The most common types of skin cancer are basal cell and squamous cell cancer. These cancers rarely spread to other parts of the body and are usually curable with treatment. The third type of skin cancer is called melanoma. Melanoma is less common than the other two, but it is more dangerous because it is more likely to spread. The majority of deaths from skin cancer are caused by melanoma.

A skin biopsy can diagnose skin cancer in the early stages when it is easier to treat.



Why do I need a skin biopsy?

You may need a skin biopsy if you have certain symptoms, for example:

  • A persistent rash
  • Scaly or rough skin
  • Open wounds
  • A mole or other growth that has an irregular shape, color, or size

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What happens during a skin biopsy?

A doctor cleans the biopsy site and injects an anesthetic so you do not feel pain during the procedure. The rest of the steps of the procedure depend on the type of skin biopsy. There are three main types:

Punch biopsy

  • The doctor places a special circular tool on the abnormal skin (lesion) and rotates it to remove a skin sample (about the size of a pencil eraser)
  • The sample is taken out with a special tool
  • If a larger sample is taken, they may need one or two stitches to cover the biopsy site
  • The pressure is applied to the region until the bleeding stops
  • The site is covered with a sterile bandage or dressing
A punch biopsy is often used to diagnose rashes.

Exfoliative biopsy

  • The doctor uses a razor blade or scalpel to take a sample from the top layer of the skin.
  • Pressure will be applied to the biopsy region to stop bleeding. You can also receive a medication that is placed on the skin (also called topical medication) to help stop the bleeding.
An exfoliative biopsy is usually used if your doctor thinks you may have skin cancer, or if you have a rash that is limited to the top layer of the skin.

Excisional biopsy
  • The surgeon uses a scalpel to remove the entire skin lesion (the abnormal part of the skin)
  • The surgeon closes the biopsy with stitches
  • The pressure is applied to the region until the bleeding stops
  • The site is covered with a sterile bandage or dressing
Excisional biopsy is often used if your doctor thinks you might have melanoma, the most serious type of skin cancer.

After the biopsy, keep the region covered with a bandage until it has healed or until the stitches come out. If you have been stitched, they will be removed 3 to 14 days after the procedure.


Will I have to do something to prepare for the test?

The skin biopsy does not require any special preparations.

Does this test have any risk?

You may have a small bruise or some bleeding or pain at the biopsy site. If these symptoms last more than a few days or get worse, talk to your doctor or health professional.

What do the results mean?

If your results are normal, that means no cancer or skin disease was found. If the results are not normal, you may be diagnosed with one of the following conditions:

  • A bacterial or fungal infection
  • Skin disease like psoriasis
  • Skin cancer. The results may indicate one of three types of skin cancer: basal cell, squamous cell or melanoma

Is there anything else I need to know about a skin biopsy?

If you are diagnosed with basal cell or squamous cell cancer, the entire cancer lesion can be removed at the time of skin biopsy or soon after. Often, no other treatment is needed. If melanoma is diagnosed, more tests are needed to see if cancer has spread. Then, you and your doctor or health professional can make the most appropriate treatment plan for you.