International Academy of Cosmetic Dermatology
Seborrheic keratoses (SKs) are one of the most common skin growths occurring on older adults. These brownish to pale lesions, sometimes even black, are flat or slightly elevated papules or plaques ranging from a few millimeters to over 2.5 cm in diameter. They can present as solitary or - more commonly - clustered lesions, on the face, neck, chest, back and extremities. Their waxy, scaly surface gives a “stuck on” appearance. Although typically harmless, they can be “dangerous-looking,” when there are brown – black discolorations, becoming reminiscent of a melanoma.
It is unclear what causes the appearance of SKs. Because they occur in families, some observers have thought genetics might play a role, while other researchers have wondered if the human papillomavirus (wart) virus might cause SKs. There are even those who have noted more SKs inpatients with more UV light exposure. In any event, they are more common with advancing age and have been called old-age marks and seborrheic warts.
SKs acquire time to develop. Unless they suddenly appear in clusters, they remain harmless. These lesions are painless, but, sometimes, they may be associated with itching, leading to redness from scratching. They can be clinically diagnosed during a routine dermatologic examination and further confirmed by histopathologic sampling, when there is concern.
Treatment for asymptomatic SKs is not necessary. The reasons for removal include irritation from clothing or jewelery, picking by the patient or grandchildren, concern over skin cancer, or anxiety about malignancy on the part of a companion. There is no magic potent to eliminate or prevent SKs and treatment is by destruction: cryosurgery (freezing) with liquid nitrogen spray or q-tip applicator; curettage (scraping a special instrument); or electrocautery (burning with a Bovie® or Hyfercator® utilizing an electric needle). Chemicals, such as salicylic acid preparations, can be used to peel down the lesions.
Maria M. Tsoukas, MD, PhD