Pigmented purpuric eruptions.

The pigmented purpuric eruptions most likely represent a group of clinical patterns of erythrocyte extravasation due to pericapillary inflammation. This inflammatory reaction may be in response to an immunologic reaction of some type, as suggested by immunopathologic studies and by the drug-induced pigmented purpuras. It is important to recognize this group of cutaneous purpura primarily to distinguish the pigmented purpuric eruptions from other types of purpura which are associated with systemic illness. The various eponyms or descriptive types of the pigmented purpuric eruptions are of historical and dermatologic interest; there is little clinical use in distinguishing among the types for a given patient.