Seborrheic keratoses are superficial, often pigmented, epithelial lesions that are usually warty but may occur as smooth papules.
The cause is unknown, but genetic mutations have been identified in certain types. The lesions commonly occur in middle age and later and most often appear on the trunk or temples. In darker-skinned people, multiple 1- to 3-mm lesions can occur on the cheekbones; this condition is termed dermatosis papulosa nigra.
Seborrheic keratoses vary in size and grow slowly. They may be round or oval and flesh-colored, brown, or black. They usually appear stuck on and may have a verrucous, velvety, waxy, scaling, or crusted surface.
Diagnosis is clinical.
They are not premalignant and need no treatment unless they are irritated, itchy, or cosmetically bothersome. Lesions may be removed with little or no scarring by cryotherapy (which can cause hypopigmentation) or by electrodesiccation and curettage after local injection of lidocaine.
Last full review/revision March 2013 by Denise M Aaron, MD
Content last modified November 2013