Necrotizing lymphocytic folliculitis: the early lesion of acne necrotica (varioliformis).

Skin biopsy specimens from four patients who had recurrent bouts of lesions conforming to the clinical description of acne necrotica were studied. The pathologic findings were dominated by lymphocytic inflammation around centrally placed follicles evolving to follicular necrosis that extended to the perifollicular epidermis and dermis. Early lesions showed the development of multiple individual necrotic keratinocytes within the follicular sheath and adjacent epidermis with lymphocytic exocytosis. Later lesions showed more intense necrosis and scale crust obscuring the central target but were still dominated by a peripheral lymphocytic infiltrate. The early pathologic findings of acne necrotica (varioliformis) are represented by a necrotizing lymphocytic folliculitis and differ from the pattern seen in association with nonspecific excoriations, acute bacterial folliculitis, classic comedogenic acne, or acnitis.