Pityriasis rosea evidence for and against an infectious aetiology

Abstract

Pityriasis rosea, first named as such in 1860, probably holds the longest record for an exanthem suspected to be associated with an infection but for which an exact cause has not been found. The distinctly programmed clinical course, the lack of recurrence for most patients, and the presence of temporal case clustering provide the strongest evidence to support an infectious aetiology. Further support comes from seasonal variation and the association with respiratory tract infections, the unfavourable social and economic background of cases, and a history in some cases of contact with patients with pityriasis rosea. The apparent therapeutic efficacy of several treatment modalities does not provide strong evidence for or against an infectious aetiology. The roles of human herpesvirus 7 and to a lesser extent human herpesvirus 6 remain controversial. There exists reasonable evidence that pityriasis rosea is not associated with cytomegalovirus, Epstein-Barr virus, parvovirus B19, picornavirus, influenza and parainfluenza viruses, Legionella spp., Mycoplasma spp. and Chlamydia spp. infections. Evidence is also unsubstantiated as yet for alternative aetiological hypotheses such as autoimmunity, atopy, and genetic predisposition.

Pityriasis Rosea: Clinical Study and Effect of Erythromycin on Its Clinical Course

“…Atopy has been shown to be more common in Pityriasis Rosea than in controls 17 . Pityriasis Rosea is relatively common in patients with seborrhoeic dermatitis and acne vulgaris 18 .…”

Demographical and Clinical Characteristics of Patients with Pityriasis Rosea in 1 Year in A Tertiary Care Hospital

“…PR görülme sıklığı ile mevsimler arasında ilişki olmadığını saptayan çalışmalar olmakla birlikte, hastalık bazı çalışmalarda sıcak mevsimlerde bazılarında ise soğuk mevsimlerde daha yüksek prevalansta bildirilmiştir (1)(2)(3)(4)7,11). Bu çalışmada da ülkemizden yapılan diğer çalışmalarla (7,9,12,13) uyumlu olarak hastalık en sık kış mevsiminde (%41,4) saptanmıştır.…”

“…Hastalığın, inokülasyon bölgesinde öncü bir plakla başlaması ve bunu daha yaygın ikincil döküntünün izlemesi, sonra da kendiliğinden iyileşmesi enfeksiyöz etyolojiyi desteklemesine karşın kesin bir etyolojik etken tespit edilememiştir (3). Enfeksiyöz olmayan etkenlerle de ilişkisi araştırılan hastalık, gerek etyolojisi gerekse farklı klinik görünümleri ile dikkat çekici bir konu olmaya devam etmektedir.…”

Piracy on the molecular level: human herpesviruses manipulate cellular chemotaxis

“…Clinically it has been associated with the development of pityriasis rosea, post-infectious myeloradiculoneuropathy, encephalopathy and other syndromes. There is some speculation on the involvement of HHV-7 in the development and progression of these diseases (Chuh et al, 2004;Mihara et al, 2005;van den Berg et al, 1999). HHV-7 infections can have a variety of symptoms, including fever, rash, febrile respiratory problems, vomiting and diarrhoea (Clark et al, 1997;van den Berg et al, 1999).…”