Skin biopsy

By SickKids staff

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Find out how a doctor uses a skin biopsy to diagnose a change or growth on the skin.

Key points

A biopsy involves removing a small piece of skin to help diagnose the cause of skin changes.
A doctor may do a punch, an excisional or a shave biopsy, depending on what your child needs.
After a biopsy, the doctor will apply ointment and a bandage and may sometimes close the skin with stitches.
Call your child’s doctor or go to your nearest emergency department if your child has a fever, unusual bleeding, swelling or discharge during the first 48 hours after their biopsy.

Introduction

What is a skin biopsy?

A skin biopsy is a procedure that helps a doctor diagnose a skin lesion (a change or growth on the skin) or a skin rash.

It involves taking a small sample of skin and sending it to a laboratory for testing. There, the skin cells and skin structure are studied closely to check for any signs of a skin disease, such as dermatitis or melanoma. The results of the biopsy can help diagnose your child’s condition.

More information

Types of biopsy

Your doctor will decide the type of biopsy depending on the type of skin lesion and the information they are looking for. The most common options are:

punch biopsy
excisional biopsy
shave biopsy.

Punch biopsy

A punch is a tool that creates a small hole in the skin, usually to the depth of a paper cut. It looks like a tiny cookie cutter. The doctor will use this circular instrument to remove a small cylinder of skin tissue, usually 3 to 4 mm wide.

Excisional biopsy

An excision involves cutting out a specific area of skin (for example, removing a mole). The doctor will use a scalpel to remove the skin.

Shave biopsy

A shave biopsy uses an instrument with a small blade to remove some of the top layer of skin.

Test

What happens during a skin biopsy?

The first part of the skin biopsy, removing a piece of skin, takes place in the hospital clinic and is quite quick.

Just before the procedure, the doctor will inject a local anaesthetic to numb the skin. The injection may be uncomfortable at first, but it will prevent your child from feeling any pain while the doctor removes the skin sample.

If your child is afraid of needles, they can receive a special cream to numb the skin (called a topical anaesthetic) to reduce some of the feeling of the needle for the local anaesthetic. Younger children may also be able to play games, blow bubbles or watch a movie to distract them during their biopsy.

After the test

What happens right after the biopsy?

The doctor may decide to close the biopsy site with stitches and will cover the skin with a bandage. If your child does not need any stitches, the doctor will make sure the bleeding stops before putting the bandage on.

Stitches

Stitches control bleeding and can make a scar appear more like a healed line than a healed circle. Whether your child will need stitches depends on the type of biopsy they have.

In shave biopsies and very small punch and excision biopsies, the doctor might decide not to use stitches. This will leave a small circular scar.
For larger biopsies, the doctor will likely close the area, usually with non-dissolvable stitches. This means that the stitches will need to be removed after several days. Your doctor will give you instructions about removing the stitches.

Bandage

All biopsy sites will be covered with a bandage, even if no stitches are needed.

If the area is not bleeding, the doctor will apply ointment and a bandage to the skin.
If the area is bleeding, the doctor or nurse will apply medication to help stop the blood flow or will apply pressure to the area until bleeding stops. They will then apply a bandage.

Your doctor will tell you how to care for your child’s biopsy wound at home.

What to expect after a biopsy

Most of the time, skin biopsies heal very well without any problems. Because the procedure involves cutting into the skin, however, there can sometimes be related complications such as bleeding or infection. A small scar will also develop at the site of the biopsy.

Helping your child

When can my child return to their usual activities?

Your child can usually continue their normal day-to-day routine once they are moving comfortably and not straining the area around their biopsy site.

Speak to your child’s doctor about when your child can return to any special activities. They may recommend, for example, that your child wait a few days before returning to swimming or to any high-impact sports that could interfere with skin healing.

Follow-up care

When will I find out about my child’s biopsy results?

It takes a few weeks to get the results of a biopsy. The team will decide with you when to follow up in the clinic to review the results.

When to seek medical attention

When to see a doctor after a biopsy

Call your child’s doctor or go to the nearest emergency department if, during the first 48 hours, your child has:

a fever greater than 38°C (100.4°F)
a lot of swelling, discharge or a change in colour (including redness) around the biopsy site
excessive bleeding around the biopsy site
severe pain or other change in sensation at the biopsy site.

Last updated: June 13th 2016