Punch Biopsy

What is a punch biopsy?

A punch biopsy is a quick, simple procedure in which a small, round sample of skin is removed using a circular blade, rather like a tiny pastry cutter. The sample is usually between 2 and 6 mm across, most often 3 or 4 mm, and includes the full thickness of the skin. It is carried out under local anaesthetic.

What is it used for?

A punch biopsy is used to help make a diagnosis when it is not clear from examination alone. It is commonly used for rashes and inflammatory skin conditions, scarring hair loss, nail and genital skin conditions, and for sampling part of a larger skin lesion, such as a suspected basal cell carcinoma, to confirm the diagnosis and subtype before deciding on treatment. Very small lesions can sometimes be removed completely with a punch.

Before your procedure

If you have private medical insurance, you will be given a procedure code. Please contact your insurer to obtain pre-authorisation, and check whether any excess applies, before booking. If you are self-funding, the clinic can give you the cost in advance.

Please tell us if you take any medicines that thin the blood, such as aspirin, clopidogrel, warfarin, apixaban or rivaroxaban, if you have a pacemaker or other implanted cardiac device, if you have ever reacted to a local anaesthetic, or if you are pregnant or breastfeeding. Do not stop any prescribed medicine unless you have been advised to.

You can eat and drink normally on the day. Try not to book the procedure in the two weeks before a holiday, an important event or a period of heavy physical activity, and avoid sun exposure, sea water and swimming while the wound heals.

If you need to cancel, please let the clinic know with as much notice as possible rather than on the day.

What happens on the day?

Dr Mounsey carries out the procedure himself. The area is cleaned and a small amount of local anaesthetic is injected. This stings briefly, then the skin becomes numb. The punch blade is pressed into the skin and turned to remove a small cylinder of skin, which is sent to the laboratory.

The small wound is usually closed with one or two stitches, which may be dissolvable or may need removing. Sometimes, for very small biopsies, the wound is left to heal on its own. A plaster is then applied. The procedure itself takes only a few minutes.

What to expect afterwards

A punch biopsy usually heals well and leaves a small scar, often a short line or a small round mark a few millimetres across. On the scalp, there will be no hair growth within the small scar.

Aftercare

Keep the plaster put on at the end of your procedure in place for the first 48 hours. After 48 hours, take it off, clean the wound with soap and water, then pat it dry. You can shower daily from this point. Each day, continue to clean the wound with soap and water, pat it dry, then apply a thin layer of Vaseline before putting on a fresh plaster. Continue this until the wound has healed.

Avoid swimming, baths and hot tubs, and avoid vigorous exercise that stretches the area, for about a week.

Stitches that need removing are usually taken out between 4 and 14 days afterwards, depending on the site, with those on the face removed earliest.

If the wound bleeds, press firmly on it with a clean, folded cloth or gauze for 10 to 15 minutes without lifting to check. If it is still bleeding after a second period of firm pressure, seek medical advice.

Paracetamol can be taken for discomfort once the local anaesthetic wears off. Avoid aspirin and anti-inflammatory painkillers such as ibuprofen for the first couple of days unless they have been prescribed for you, as they can increase bleeding. Avoiding alcohol for 48 hours and not smoking or vaping while the wound heals both help healing.

Contact the clinic if you notice signs of infection, such as increasing pain, redness, warmth or swelling around the wound, pus, or a fever, or if you have any other concerns.

Once the wound has fully healed, protect the scar from the sun with a broad-spectrum sunscreen of SPF 30 or above for at least six months, as sun exposure can darken or redden a new scar.

What are the risks?

Punch biopsies are very safe. Risks include discomfort, bleeding, infection, a scar that is raised, indented or a different colour, and, rarely, damage to a small nerve, which can cause numbness. Occasionally, the sample does not give a definite answer and a further biopsy is needed.

Results and follow-up

Results are usually available within one to two weeks, and sometimes longer for samples that need special tests. A follow-up appointment, which may be virtual, will be arranged to discuss the results and the next steps. If you have not heard about your results within three weeks, please contact the clinic.

More information

If you have any questions about your procedure, please contact the clinic before booking.

This page gives general information only and is not a substitute for a consultation. Everyone's skin is different, and what is right for you will depend on your own circumstances. If you are worried about a skin problem, please book an appointment with Dr Mounsey or speak to your GP. If you have a mole or skin lesion that is changing, bleeding or growing quickly, please seek medical advice promptly.