What Is a Seborrhoeic Keratosis?

The appearance of seborrhoeic keratosis is a very common sign of ageing for 90% of adults who are 60 and older. In medical dermatology, it is also known as basal cell papilloma, brown wart, or senile wart. Seborrhoeic keratosis can appear on any area of the skin except the palms and soles. Its appearance is very variable, starting from a 1 mm in diameter flat spot (macule) or raised papule, which can be light brown, dark brown, yellow, identical to the skin colour, or mixed. The surface can be warty, waxy, or smooth to touch. The condition may appear as an individual spot or cluster in the areas of the scalp, spine, groin, or under the breasts or chest.

In nature, seborrhoeic keratosis is degenerative. It expands in number with time. Some patients are predisposed to the development of numerous lesions. Based on recent research, eruptive seborrhoeic keratosis can be triggered by sunburn and/or dermatitis. If a lesion appears in the body folds, it can be the result of unintentional skin friction. Mutations of the genes PIK3CA, RAS, AKT1, and FGFRS3 are responsible for the condition of seborrhoeic keratosis. These mutations are often triggered with age and by ultraviolet radiation.

Even though seborrhoeic keratosis is not a premalignant lesion or a malignant tumour, it is closely connected with skin cancer. In some cases, skin cancer may occur simultaneously, or skin cancer and seborrhoeic keratosis cannot be distinguished without further medical assessment. Additional information is available on non-melanoma skin cancer.

Further information on dermato-oncology is also available.

Seborrhoeic keratosis is usually identified through clinical assessment that includes dermatoscopy. Dermatoscopy is a tool for skin examination that uses skin surface microscopy to examine the structure and patterns of a patient's skin. The common dermatoscopic cues for this condition are visible milia-like cysts and comedo-like openings.

Seborrhoeic keratosis can be removed through several methods, depending on the type of lesion. Flat lesions can be removed or lightened with the assistance of a laser. Thicker lesions can be removed with the use of cryosurgery (liquid nitrogen), curettage, or electrosurgery.