Pityriasis rosea--a virus-induced skin disease? An update.

Pityriasis rosea (PR) is an acute, inflammatory skin disease of unknown cause. Clinical and experimental findings indicate an infectious etiology of PR. Various infectious agents including viruses have been proposed as causative agents and their presence in PR samples has been extensively investigated. Recently, human herpesvirus 7 was linked to PR, but contradictory findings have been reported by various investigators. Here, we describe the features of PR that suggest an infectious cause and review the data from viral studies in PR reported in the literature. In addition, we present a pathogenetic model of PR which may be helpful in planning and evaluating studies for the search of a putative PR-associated virus. Based on the current state of knowledge, none of the known viruses could, so far, be conclusively associated with PR.