The lesions often have the appearance of being stuck on and are characterized by prominent follicular plugging. The differential diagnosis of seborrheic keratosis and dermatosis papulosa nigra includes lentigo, wart, and nevus cell nevus. A biopsy may be required to rule out a pigmented basal cell carcinoma or, in the case of an inflamed seborrheic keratosis, malignant melanoma or squamous cell carcinoma. A shave biopsy that includes the base of the lesion may be performed before treatment with curettage.
Curettage is a satisfactory treatment.
When multiple lesions are present, anesthesia may be obtained by freezing the affected area with an ethyl chloride spray before performing curettage. For larger lesions, electrodesiccation is unnecessary and may cause scarring. Epidermal nevus Epidermal nevus consists of closely set, skin-colored or hyperpigmented papules that either may be localized to one side of the body and arranged in linear fashion or may be widespread. When widespread, it is called systematized nevus. Lesions affect about one in 1,000 people and are present at birth or appear in early childhood.