Seborrhoeic keratosis

What are the aims of this leaflet?

This leaflet has been written to help you understand more about seborrhoeic keratoses. It explains you what they are, what causes them, what can be done about them, and where you can find more information.

What are seborrhoeic keratoses?

Seborrhoeic keratoses (SK) are also known as seborrhoeic warts and basal cell papillomas. They are benign growths caused by a build-up of skin cells. SK are very common, harmless, often brown/black, growths on the skin. In the UK more than half the men and more than a third of women have at least one SK. By the age of 40, 30% of the population are affected while by the age of 70 it increases to 75%. They are also found in younger people. The number of SK varies from person to person.

They are not infectious and do not become skin cancer.

What causes seborrhoeic keratoses?

Despite their name, SK are nothing to do with sebaceous (oil) glands or viral warts. It is unknown what causes them. It has been suggested that sunlight is a risk factor.

Are seborrhoeic keratoses hereditary?

Some people may inherit a tendency to develop SK.

What are the symptoms of seborrhoeic keratoses?

SK are harmless, and usually do not cause symptoms. They can sometimes itch, become red and sore, and catch on clothing. Many people dislike the look of them, particularly when they occur on their faces.

 What do seborrhoeic keratoses look like?

SK have a rough surface, and range in colour from pink to almost black. They can affect anyone, but on dark-skinned people they can also appear as a lot of small dark brown or black bumps, especially on the face and the neck (this is called dermatosis papulosa nigra).

Small flat SK can often become more raised and larger as the years go by. Their size varies from less than one centimetre to several centimetres across. They give the impression that they are stuck onto the surface of the skin.

SK occur most often on the trunk, but are also common on the head and neck. The numbers vary and one person may have just one SK whilst others may have many. Once present, they usually remain and new ones may appear over the years.

How are seborrhoeic keratoses diagnosed?

SK are much more common than skin cancers; however, a very dark seborrhoeic keratosis can look similar to a melanoma. It is therefore important that either a general practitioner or specialist checks any changing brown/black lesions to ensure they are a SK.

SK can become a worry if they are red, itchy, sore or bleeding. If there is any doubt, a skin biopsy can be done.

Can seborrhoeic keratoses be cured?

Individual SK can be treated successfully in the ways listed below, although they can regrow in the same site and may continue to appear in other places on the body.

How can seborrhoeic keratoses be treated?

Treatments for SK are not funded by the NHS.  SK do not need treatment as they are harmless and cause no symptoms; however, for those who wish to have them removed (usually in the private sector) options include freezing them with liquid nitrogen (cryotherapy), laser, or scraping them off (curettage) under a local anaesthetic.

What can I do?

Always contact your doctor if you are worried about a pigmented spot that is changing in any way.

Where can I get more information about seborrhoeic keratoses?

Web link to detailed leaflets:

For details of source materials used please contact the Clinical Standards Unit (

Please note that the BAD provides web links to additional resources to help people access a range of information about their treatment or skin condition. The views expressed in these external resources may not be shared by the BAD or its members. The BAD has no control of and does not endorse the content of external links.

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel





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