Seborrhoeic keratoses (SK) are also known as seborrhoeic warts, and as basal cell papillomas. They are benign growths due to a build-up of skin cells.
SK are very common, harmless, often pigmented, growths on the skin. In the UK more than half the men and more than third of women would have at least one SK. By the age of 40 30% of the population would be affected while by the age of 70 it increases to 75%. They are also found in younger people.
Some people will have only few seborrhoeic keratoses, while others will have large numbers.
They are not infectious and do not become skin cancer.
Despite their name, SK are nothing to do with sebaceous glands or viral warts. We don’t know what causes them. It has been suggested that exposure to sunlight and the human papilloma virus (HPV) are risk factors.