Pigmented purpuric dermatoses (PPD) are group of benign chronicdiseases of unknown aetiology that are similar in clinical and histologicalappearance. In addition to having comparable morphology, thesedisorders exhibit a distribution that is remarkably alike. Clinically theyare characterized by petechiae and brownish pigmentation, particularly onthe lower extremities, especially of young adults, without any associatedhematologic disorder or obvious venous insufficiency.Immunohistologic studies using monoclonal antibodies performed inpigmented purpuric dermatoses in order to find out the major infiltratingcells in the dermis and compare the nature with those found with otherinflammatory dermatoses, in a trial to explain the cellular immunereaction role and hope of better understanding of the pathogenesis of thedisease.Examination of the level of T helper/ inducer lymphocytes (CD4), Tcytotoxic/ suppressor lymphocytes (CD8) and B lymphocytes (CD20) inthe lymphocytic infiltrate in the dermis of the lesional skin. In order tounderstand the pathogenesis of this, still termed idiopathic disorder.