Purpura annularis telangiectoides.

Purpura annularis telangiectoides of Majocchi (PATM) is a clinical variant of pigmented purpuric dermatoses. It is characterized by asymptomatic or mildly pruritic, erythematous, annular patches that vary in size. The patches exhibit central clearing and peripheral cayenne pepper petechiae. It classically occurs on the lower legs but may be more generalized. Histopathologic features include a lymphocytic capillaritis with subsequent capillary leakage and extravasated erythrocytes, which is typical of all pigmented purpuric dermatoses. The pathogenesis of PATM is unknown, but it may uncommonly be associated with underlying diseases such as hematologic disorders and rarely cutaneous T-cell lymphoma. There is no standard effective treatment.