Inflammatory stage of disseminated superficial porokeratosis

Disseminated superficial porokeratosis (DSP) is a keratinization disorder characterized by multiple small lesions with a slightly elevated, sharply defined ridge over the whole body. Unusual DSP cases with acute exacerbation of their lesions accompanied by severe pruritus have been reported and designated as "eruptive pruritic papular porokeratosis" or "inflammatory DSP". Histologically, the pruritic lesions in the majority of these unusual DSP cases had a dense infiltration of eosinophils and lymphocytes in the vicinity of blood vessels in the upper dermis. In this report, we describe an additional case of DSP with a similar clinical course and histopathological findings. A review of the literature showed that the pruritic condition in these unusual DSP cases can be transient and is not necessarily related to spontaneous regression. We propose the term "Inflammatory stage of DSP" for describing this unusual variant of DSP.