A 28-year-old Hispanic woman presents for evaluation of a minimally pruritic dermatitis involving her chest, back, and abdomen. The rash began three weeks ago at which time she was diagnosed elsewhere with an “allergic reaction” and placed on cetirizine. Examination reveals multiple erythematous to hyperpigmented papulosquamoid patches. Her palms, soles, and oral mucosa are unaffected. She insists on a biopsy because she says, “I am totally freaked out.”
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Pityriasis rosea (PR) manifests as an acute, self-limiting papulosquamous eruption that lasts on average 6 to 8 weeks.1 PR is observed in all age groups, though it is most common in persons aged 10 to 35 years and rare in infants and the elderly. No racial predominance has been reported. The condition evolves rapidly often beginning as a solitary ovoid erythematous rash that precedes the eruption, aptly named the “herald patch.” Atypical variants are not uncommon and the disorder may resemble other skin conditions such as tinea corporis, secondary syphilis and drug eruptions.2-4 As a rule, PR requires only symptomatic treatment, although extensive cases may benefit from oral steroids.
The cause of PR is uncertain, and an infectious etiology has been suspected for decades.5 Several studies link the disease to reactivation of certain strains of the herpes virus (human herpesvirus-6 and -7).6,7 PR-like eruptions have also been linked to many drugs.3
Michael Stas, DPM, is a podiatry-dermatology fellow at St. Luke’s University Hospital in Bethlehem, Pennsylvania, and at the DermDox Dermatology Center in Hazleton, Pennsylvania. Stephen Schleicher, MD, is an associate professor of medicine at the Commonwealth Medical College in Scranton, Pennsylvania, and an adjunct assistant professor of dermatology at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. He practices dermatology in Hazleton, Pennsylvania.
- Schwartz RA. Pityriasis rosea. Medscape website. http://emedicine.medscape.com/article/1107532-overview Updated June 2, 2016. Accessed November 3, 2016.
- Allen RA, Janniger CK, Schwartz RA. Pityriasis rosea. Cutis. 1995;56(4):198-202.
- González LM, Allen R, Janniger CK, Schwartz RA. Pityriasis rosea: an important papulosquamous disorder. Int J Dermatol. 2005;44(9):757-764.
- Browning JC. An update on pityriasis rosea and other similar childhood exanthems. Curr Opin Pediatr. 2009;21(4):481-485.
- Chuh A, Chan H, Zawar V. Pityriasis rosea—evidence for and against an infectious aetiology. Epidemiol Infect. 2004;132(3):381-390.
- Broccolo F, Drago F, Careddu AM, et al. Additional evidence that pityriasis rosea is associated with reactivation of human herpes virus-6 and -7. J Invest Dermatol. 2005;124(6):1234-1240.
- Watanabe T, Kawamura T, Jacob SE, et al. Pityriasis rosea is associated with systemic active infection with both human herpesvirus-7 and human herpesvirus-6. J Invest Dermatol. 2002;119(4):793-797.