Pityriasis rosea in a hepatitis B-positive patient treated with pegylated interferon α2a: report of a case and review of the literature.

Pityriasis rosea (PR) is an acute, self-limiting exanthematous disease caused by the endogenous reactivation of human herpesvirus (HHV)-6 and/or HHV-7 infection in conditions of altered immunity. In addition, many drugs have been incriminated as possible triggers of PR-like eruptions, characterized by clinical, morphological and histopathological features that differ from typical PR. Here, we report a case of PR in a patient with chronic hepatitis B, receiving pegylated interferon α2a (PEG-IFN-α2a). PR, arising after the second administration of the PEG-IFN-α2a, might be considered a clinical expression of the patient's altered immune condition as reported in the immune reconstitution inflammatory syndrome affecting patients with human immunodeficiency virus infection after high-dose antiretroviral therapy.