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Pityriasis rosea--evidence for and against an infectious aetiology

A Chuh1, H Chan, V Zawar

  • 1Department of Medicine, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong SAR, China.

Epidemiology and Infection
|June 11, 2004
PubMed

Insights

Pityriasis rosea, a skin rash, is likely caused by an infection, though the exact cause remains unknown. Research suggests links to viruses like human herpesvirus 7, but other causes are unlikely.

Area of Science:

  • Dermatology
  • Infectious Diseases
  • Epidemiology

Background:

  • Pityriasis rosea is a common exanthem with a long history of suspected infectious etiology.
  • Despite extensive research since 1860, its precise cause remains elusive.
  • Clinical features like distinct progression, low recurrence, and case clustering suggest an infectious origin.

Purpose of the Study:

  • To review the evidence for and against various etiological hypotheses for pityriasis rosea.
  • To critically evaluate the role of specific viral and microbial agents.
  • To assess alternative theories such as autoimmunity and genetic predisposition.

Main Methods:

  • Literature review and critical analysis of existing studies.
  • Evaluation of epidemiological data, including seasonal variations and contact history.
  • Assessment of evidence linking specific pathogens, including human herpesviruses.

Main Results:

  • Strong evidence supports an infectious etiology for pityriasis rosea.
  • Human herpesvirus 7 (HHV-7) and human herpesvirus 6 (HHV-6) roles are debated.
  • No significant association found with cytomegalovirus, Epstein-Barr virus, parvovirus B19, picornaviruses, influenza, parainfluenza viruses, Legionella, Mycoplasma, or Chlamydia.

Conclusions:

  • Pityriasis rosea is most likely infectious in origin.
  • Current evidence does not support autoimmunity, atopy, or genetic predisposition as primary causes.
  • Further research is needed to definitively identify the causative agent, with HHV-7 being a potential candidate.

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