Human herpes virus-like particles in pityriasis rosea lesions: an electron microscopy study

Background: In a previous study we detected virions with electron microscopy features of human herpes viruses in the supernatant of cocultured mononuclear cells from patients with acute pityriasis rosea. Because of their morphology and of polymerase chain reaction studies, we ascribed them to human herpes virus 7. Objective: To find such virions in the lesional skin of pityriasis rosea patients. Methods: Skin speciments from lesions of 21 patients with acute pityriasis rosea were examined by elecron microscopy. Results: In 15 (71%) patients, human herpes virus particles in various stages of morphogenesis were detected. Mature enveloped virions appeared as typical human herpes virus virions, measuring about 160-200 nm in diameter and containing an electrodense cylindrical core, a capsid, an envelope with typical spikes and a very distinct tegument layer between the capsid and the envelope. They were very similar to those we reported in the supernatant of co-cultured circulating mononuclear cells from patients with pityriasis rosea. Conclusion: Our results confirm our previous findings and provides further evidence of a viral etiology for pityriasis rosea.