Seborrheic keratoses are pigmented superficial epithelial lesions that are usually warty but may occur as smooth papules.
The cause is unknown. The lesions commonly occur in middle or old age and most often appear on the trunk or temples; in blacks and Asians, especially women, lesions that are 1 to 3 mm often 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 September 2008 by Daniel W. Collison, MD
Content last modified February 2012