A young emergency medicine nurse asks you to take a look at a rash she has developed over the last 2 weeks. She ¬†noted a single lesion on her back which is painless and not pruritic approximately 10 days ago (see below). She developed another rash along the bilateral chest which is pruritic and erythematous approximately 4 days ago made up of small circular lesions. She denies any recent fever or chills, no URI symptoms and no exposures. What’s your diagnosis? What’s your management?

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Pityriasis rosea is a self-limited benign dermal inflammatory process that is hypothesized to be of viral etiology – most likely HHV7

The initial lesion is known as the “Herald Patch” – usually 2-5 cm in diameter ¬†– initially pink it then develops scaled edges and central clearing. This lesion usually develops on the chest, neck or back.

Within 1-2 weeks additional smaller lesions similar to the herald patch but of smaller diameter develop on the trunk and proximal extremities in the distribution of cleavage lines which results in the classic “Christmas tree” distribution.

Treatment is usually limited to supportive care and topical steroids for symptom relief. Studies have been done with erythromycin and acyclovir but evidence of true benefit is limited.

Symptoms can persist for up to 3 months and follow up is usually not necessary.

Of note, women who are pregnant may have an increased risk of spontaneous abortion with concurrent PR.

  1. Drago F, Ranieri E, Malaguti F, et al. Human herpesvirus 7 in patients with pityriasis rosea. Electron microscopy investigations and polymerase chain reaction in mononuclear cells, plasma and skin. Dermatology 1997; 195:374.
  2. Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol 2009; 61:303.
  3. Drago F, Broccolo F, Zaccaria E, et al. Pregnancy outcome in patients with pityriasis rosea. J Am Acad Dermatol 2008; 58:S78.