Seborrhoeic keratoses

What are seborrhoeic keratoses?

Seborrhoeic keratoses (seb K), also known as seborrhoeic warts and basal cell papillomas, are benign (harmless) growths caused by a build-up of skin cells. They cannot turn into skin cancer.

Seb K are extremely common; almost everyone older than 50 has at least one, some people have many more. Seb K are uncommon under the age of 20 years.

What do seborrhoeic keratoses look and feel like?

• Often multiple but can be solitary. May be grouped in certain areas such as under the breasts and in the groin
• Vary in size from a few mm to several cm
• Often brown/black, but can be skin-coloured or pink
• Raised, often with a crusty/warty surface, but can be smooth or waxy to the touch
• Can feel itchy, and may be easily traumatised e.g. by catching on clothing or jewellery and bits can drop off or they may bleed. Any inflammation (redness) should settle within a few weeks

What causes seborrhoeic keratoses?

The cause is not known. Seb K are nothing to do with sebaceous (oil) glands or viral warts. They are not infectious (i.e. cannot be passed from one person to another). In people with a large number of seb K there can be a hereditary component (i.e. another family member may also have many seb K). Skin friction may be the reason they appear in body folds.

Things you can do to help yourself

• Diet and other lifestyle changes will not make a difference. Applying a regular emollient (moisturiser) may help, particularly if a seb K is itchy
• Learn what skin cancer looks like - for more information please refer to the advice page Self-examination of Moles

Make an appointment at your GP surgery

Most seb K do NOT need treatment. Even if they grow, they cannot turn into skin cancer. The only reasons for contacting your GP surgery are:

• If one or more of the seb K catch and bleed on a persistent basis, in which case treatment may be offered
• If you develop a skin lesion that looks different to the others i.e. an 'ugly duckling' 

Treatment for seborrhoeic keratoses

• Most seb K do not need treatment
• Those that catch and bleed repeatedly may be treated by freezing with liquid nitrogen (cryotherapy), or scraping off (curettage) using local anaesthetic
• Even with treatment, seb K can grow back
• Seb K cannot be treated on the NHS for cosmetic reasons

Can seborrhoeic keratoses be cured?

• Seb K usually persist, and you may develop more – you cannot prevent new ones from growing

Helping with other skin conditions

If you, a family member, or friend have an undiagnosed skin condition; or you want to learn more about how to treat skin conditions, please view our short video on how to get the best from this website.