A 24-year-old woman presents with concerns about a rash on her chest that she noticed 3 days ago. She complains of mild itchiness and denies other symptoms such as fever, genital lesions, swollen glands, and recent tick bite. She is on an oral contraceptive but takes no other medications. Her history is negative for eczema and psoriasis. Examination reveals a slightly elevated, scaly, erythematous plaque.
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Pityriasis rosea is an acute papulosquamous eruption. It typically begins with the appearance of an isolated plaque. The condition affects children and young adults and is slightly more common in women.1 It is characterized by rapid progression of a generalized exanthema followed by the herald patch (slightly raised scaly patch). Discrete lesions are salmon colored, surrounded by a collarette of scale, and are oriented along lines of cleavage in a Christmas tree pattern. Pruritus is often absent or mild.2
The diagnosis is clinical and based on examination and history. Most cases of pityriasis rosea resolve with 6 weeks without therapy. Extensive and highly symptomatic cases may improve with treatment with oral steroids or UV light therapy, but oral steroids are not generally recommended for mild cases.3,4
The etiology of pityriasis rosea is unknown. An infection with the herpesvirus has been postulated as a cause of pityriasis, although studies to date have been inconclusive.5 The antiviral acyclovir has been used to successfully treat florid cases.6 Most recently, there have been several case reports documenting the development of pityriasis rosea in association with SARS-CoV-2 infection.7,8
This patient in this case presented with a herald patch characteristic of pityriasis rosea. Within 3 days of appearance, multiple smaller patches arose on her trunk. She was placed on a short course of oral prednisone and advised to spend time outdoors in sunlight. The rash was beginning to fade when she was seen for follow-up 2 weeks later.
Stephen Schleicher, MD, is director of the DermDox Center for Dermatology in Pennsylvania, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Chuang TY, Ilstrup DM, Perry HO, Kurland LT. Pityriasis rosea in Rochester, Minnesota, 1969 to 1978. J Am Acad Dermatol. 1982;7(1):80-89. doi:10.1016/s0190-9622(82)80013-3.
2. Chhabra N, Prabha N, Kulkarni S, Ganguly S. Pityriasis rosea: clinical profile from Central India. Indian Dermatol Online J. 2018;9(6):414-417. doi:10.4103/idoj.IDOJ_12_18
3. Sonthalia S, Kumar A, Zawar V, et al. Double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of short-course low-dose oral prednisolone in pityriasis rosea. J Dermatolog Treat. 2018;29(6):617-622. doi:10.1080/09546634.2018.1430302.
4. Arndt KA, Paul BS, Stern RS, Parrish JA. Treatment of pityriasis rosea with UV radiation. Arch Dermatol. 1983;119(5):381-382.
5. Rebora A, Drago F, Broccolo F. Pityriasis rosea and herpesviruses: facts and controversies. Clin Dermatol. 2010;28(5):497-501. doi:10.1016/j.clindermatol.2010.03.005.
6. Ganguly S. A Randomized, double-blind, placebo-controlled study of efficacy of oral acyclovir in the treatment of pityriasis rosea. J Clin Diagn Res. 2014;8(5):YC01-04. doi:10.7860/JCDR/2014/8140.4360.
7. Veraldi S, Spigariolo CB. Pityriasis rosea and COVID-19. J Med Virol. 2021;93(7):4068. doi:10.1002/jmv.26679.
8. Ehsani AH, Nasimi M, Bigdelo Z. Pityriasis rosea as a cutaneous manifestation of COVID-19 infection. J Eur Acad Dermatol Venereol. 2020;34(9):e436-e437. doi:10.1111/jdv.16579.