The clonal nature of pityriasis lichenoides.

Background: Pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC) are benign lymphocytic infiltrates of the skin that classically present as either a recurrent papulonecrotic eruption (PLEVA) or a persistent, scaling, papular eruption (PLC). Observations of both types of lesions present on individual patients have led to speculation that both entities are related. Previous studies evaluating the DNA of biopsy specimens from patients with PLEVA and PLC revealed clonal T-cell receptor beta gene rearrangements.