What are seborrhoeic keratoses?
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 is very common, harmless, often pigmented, growths on the skin. They are not infectious and do not become skin cancer.
What causes seborrhoeic keratoses?
Despite their name, SK is 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 papillomavirus (HPV) are risk factors.
Are seborrhoeic keratoses hereditary?
Yes, some individuals may inherit the tendency to develop SK from their parents.
What are the symptoms of seborrhoeic keratoses?
SK is harmless, and usually do not cause symptoms. They can sometimes itch, become inflamed, and catch on clothing. Many people dislike the look of them, mainly when they occur on their faces.
How do seborrhoeic keratoses look like?
SK has a rough surface, and range in color from golden brown to mid brown to almost black. They can affect anyone, but on dark-skinned people, they can also appear as multiple small dark brown or black bumps, especially on the face and the neck; in such a case, this is called Dermatosis Papulosa Nigra. Small flat SK can often become more raised and larger as the years pass on.
Their size varies from less than one centimeter to several centimeters across. They give the impression that they are stuck onto the skin surface; however, some look like small pigmented skin tags.
SK occurs most often on the trunk, but they are also common on the head and neck. Their numbers vary, and one person may have just one seborrhoeic keratosis, while others can have hundreds. Once present, they usually stay, and new ones often appear over the years.
How are seborrhoeic keratoses diagnosed?
SK is 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 pigmented lesions to ensure that the correct diagnosis is made. SK can cause worry by becoming inflamed or bleeding. If there is any doubt, a skin biopsy can be done to confirm the diagnosis.
Can seborrhoeic keratoses be cured?
Individual SK can be treated successfully in the ways listed below. However, new SK may continue to appear.
How can seborrhoeic keratoses be treated?
As SK is so common, it would be impossible to treat every individual and every single keratosis routinely. Most need no treatment as they are harmless and cause no symptoms; however, for those who wish to have some of their keratoses removed, it may be possible to have them treated by a general practitioner in primary care. SK is not routinely removed in hospitals. Treatment can occur by either freezing them with liquid nitrogen (cryotherapy) or scraping them off (curettage) under a local anesthetic.