Skin biopsy

A skin biopsy is a routine test that helps us to diagnose skin conditions.

A biopsy is when we remove a small sample of skin. We can then look at this sample under a microscope to make a diagnosis. We can also use a biopsy as a treatment to remove some growths on the skin, such as moles.

We give you a local anaesthetic. This is a medicine that makes a specific area of your body numb and pain-free, but does not put you to sleep.

Before your biopsy

If you plan to travel within 2 weeks of your biopsy, please tell us. This affects the arrangements for removing your stitches (if you have them).

Some people feel light-headed after their biopsy. For your safety, you must not drive to your appointment and need someone to accompany you home. You can eat and drink as normal before your appointment.

Medicines you take

We need to know if you take some medicines because they can increase the risks of bleeding and bruising. Please tell the staff looking after you if you take:

  • antiplatelet medicines to prevent blood clots (such as aspirin or clopidogrel)
  • anticoagulant medicines to prevent blood clots (such as warfarin or rivaroxaban)

Do not stop taking any of these medicines. 

Please also tell us if you have any allergies to medicines, including local anaesthetic.

If you take warfarin

If you take warfarin, please visit your local warfarin clinic 2 to 3 days before your surgery date and have your INR checked. The international normalised ratio (INR) measures how long it takes your blood to clot.

If your INR is below 2 or above 3.5, please contact us. We might need to rearrange your biopsy date.

During your skin biopsy

We inject local anaesthetic into the area where we are taking the biopsy. This may sting for a few seconds, but then the area becomes numb.

You might feel pulling or pressure on the area when we take the biopsy, but this should not be painful.

We take a sample of tissue by cutting or scraping your skin. Depending on your situation, we might have to take more than 1 biopsy.

If we close your wound with stitches, you will need to have these removed at your GP surgery.

The whole procedure does not usually take more than 30 minutes.

After the procedure

A nurse puts a dressing on your wound and explains how to look after it before you leave hospital.

If you have stitches, your nurse will also talk to you about arrangements for getting them removed. They give you a letter to pass on to the nurse at your GP surgery.

You can leave hospital when you feel well enough, and eat and drink as soon as you want.

Painkillers for any pain or discomfort

The local anaesthetic starts to wear off about 30 to 40 minutes after your skin biopsy procedure.

If you have any discomfort from your wound, you can take simple painkillers like paracetamol to help with this. Always follow the instructions on the packet and never take more than the recommended amount (dose).

It is important to check that the painkillers do not react with any other medicines you take. If you are unsure about this or have allergies to any medicines, speak to your pharmacist.

We want to involve you in decisions about your care and treatment.

If you decide to have a skin biopsy, we ask you to sign a consent form. This says that you agree to have the procedure and understand what it involves.

There are no other options to this procedure. It is the only way to get the information that we need to make a correct diagnosis.

If you would like more information about our consent process, please speak to a member of staff caring for you.

Risks of biopsy

We talk to you about the risks in detail before we ask you to sign the consent form.

Short-term risks include infection, bleeding and swelling of your wound. Although the biopsies that we take are not large, you will have a small scar.

Follow-up appointments

We arrange a follow-up appointment to explain the results of your skin biopsy.

Resource number: 1680/VER10
Page currently under review

Contact us

Guy's dermatology outpatient department

Phone: 020 7188 6418 Monday to Friday, 9am to 5pm. 

The dermatological surgery and laser unit (DSLU) has an answer phone service.

Call 020 7188 6284 Monday to Friday, 9am to 5pm.

Please leave a message with your name and phone number. Someone will return your call as soon as possible.

In an emergency, please contact your GP or go to your nearest emergency department (A&E).

pals icon

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

Is this health information page useful?