Probing pityriasis rosea in pregnancy

By Warren R. Heymann, MD, FAAD
January 19, 2022
Vol. 4, No. 3

I have always been captivated by pityriasis rosea (PR). As a second-year medical student, my late brother Andrew (presumably) developed it. I was clueless when he showed me his rash. He immediately told my father that money was being wasted on my budding medical career — I figured that I had better take a dermatology elective sometime prior to graduation. Up until mid-career, I always delighted in rendering the diagnosis of PR because I was able to put patients at ease — as of 2008, that may not always be the case.

PR is a common self-limiting rash with an incidence of 170 cases per 100,000, typically affecting younger people (10 to 35 years old), possibly occurring more frequently in winter. Clinically, PR characteristically begins with a herald patch on the trunk and, in approximately two weeks, progresses along Langer lines to a generalized eruption (with the “Christmas tree” pattern) over the trunk and extremities. (My foremost teacher, Michael Fisher, referred to the distribution as “long-turtleneck, short sleeve”). Occasionally, lesions are limited to the axillae and groin (inverse PR, PR of Vidal). Patients may experience systemic symptoms including general malaise, fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, and sore throat before or during the course of disease. The mean duration of PR is 45 days; cases may last up to 12 weeks. The differential diagnosis includes secondary syphilis, seborrheic dermatitis, nummular eczema, pityriasis lichenoides chronica, tinea corporis, viral exanthems, lichen planus, and drug-induced pityriasiform eruptions. The diagnosis is usually based on physical examination, although biopsies and serologic studies may be valuable in atypical or equivocal cases. Treatment focuses on alleviating symptoms with initial use of corticosteroids or antihistamines. In some cases, acyclovir can be used to treat symptoms and shorten the length of disease. Ultraviolet phototherapy may be valuable for severe cases. (1)

One of the joys of diagnosing PR is in confidently reassuring anxious patients that their rash will resolve without sequelae, with only a remote chance of recurrence. There is one important exception to this blissful scenario — contracting PR during pregnancy.

PR may be seen more frequently during pregnancy. This association was first considered by Corson and Luscombe in 1950. Their study was small — of 76 female patients with PR, 14 (18%) were pregnant, with 3 of the 14 being in the first half of their gestation. This compared to pregnancy in 6 of 100 (6%) women with non-PR dermatoses. (2)

As aptly stated by Rebora et al, “Any infectious illness presenting with an eruption in a pregnant patient may be associated with an increased risk of fetal loss. The viruses that can infect the placenta during maternal infection and can be transmitted to the fetus and cause congenital disease include the rubella virus, the measles virus, the varicella zoster virus, parvovirus B19, human cytomegalovirus, arboviruses [such as Zika], and hepatitis E virus type 1. In addition, some bacteria responsible for exanthematous diseases, like Treponema pallidum, can be transmitted during pregnancy from the mother to the fetus and cause fetal loss. All these infectious agents can cause typical and/or atypical exanthems whose etiologic diagnosis is sometimes difficult but important to determine, especially in pregnant women because of the potential risk to the fetus.” (3)

Although the precise etiology of PR remains to be determined, it has been associated with reactivation of human herpes viruses HHV-6 and HHV-7. Immunosuppression may favor reactivation; immunodysregulation accompanies gestation. In 2008, Drago et al investigated the possible impact of PR in pregnant women. Of the 38 women assessed, 9 had a premature delivery and 5 miscarried. Notably, 62% of the women who developed PR within 15 weeks' gestation aborted. Neonatal hypotonia, weak motility, and hyporeactivity were observed in 6 cases. In one patient studied in detail, HHV-6 DNA was detected in plasma, peripheral blood mononuclear cells, skin, and placenta and embryonic tissues, whereas HHV-7 DNA was absent. HHV-6 p41 antigen was detected by immunohistochemistry in skin lesions, placenta, and embryonic tissues. No herpesvirus DNA was detected in plasma and tissues from control subjects. The authors concluded that “PR may be associated with an active HHV-6 infection. In pregnancy, PR may foreshadow premature delivery with neonatal hypotonia and even fetal demise especially if it develops within 15 weeks’ gestation.” In a follow-up study of 61 women clinically diagnosed with gestational PR, 61 patients carried HHV-6/7 IgG, but none had detectable IgM antibodies. The total abortion rate (8 of 61, 13%) was similar to the prior series. When PR developed within the 15th gestational week (14 cases), the abortion rate of 57% (8 of 14). (5)

Most recently, Stashower et al reported their experience in 33 pregnant women with PR. Of the 33 patients, 8 (24%) had birth complications (such as small for gestational age, fetal distress, oligohydramnios, and others). These complications were considered minor; importantly, no fetal deaths, abortions, or miscarriages were observed. Women with birth complications had an earlier average onset of PR than those who did not — 10.75 versus 15.21 weeks gestation respectively — this difference was not statistically significant. (6)

Until future studies clarify this association, how should dermatologists manage pregnant patients with PR? I concur with the reasonable approach of Alajmi et al who state that pregnant women with PR require close monitoring especially during the first 15 weeks of pregnancy. Despite the absence of consensus on treatment, there is some evidence of the benefit of acyclovir and that it is a very safe treatment even in pregnancy. (7). Consultation with the patient’s obstetrician is essential.

Point to Remember: Patients who develop pityriasis rosea during pregnancy may be at risk for spontaneous abortion and other complications. Although more studies are warranted to further define the risk, consideration should be given for the use of acyclovir during gestation.

Our expert’s viewpoint

Hal Flowers, MD, FAAD
Assistant Professor of Dermatology
University of Virginia School of Medicine

Our rapidly expanding knowledge about SARS-CoV-2 and COVID-19 over the past year — its clinical manifestations, treatment, and preventive aspects — illuminates just how much can be learned from well-aimed research efforts. Such is also the case with pityriasis rosea, an old disease that is still yielding new secrets. The characteristic presentation of pityriasis rosea (PR) has been well-defined since the 1860s. However, it was not until 1997 that Drago et al first proposed the link between PR and HHV-7 and -6 reactivation (8) and a decade later when they reported an association with poor pregnancy outcomes (4).

Our multicenter retrospective analysis did not find as high a rate of adverse pregnancy consequences as the prior two studies. After reading our study, one may be tempted to downplay the potential impact of PR on a pregnancy. Ideally though, our study would produce hope that the risk of PR in pregnancy is somewhat less than formerly shown. More importantly, the study would spur further investigation into this important clinical question. Until we have more definitive data on the risk of pityriasis rosea in pregnancy, I agree with Dr. Heymann’s dependably rational and thoughtful suggestions: close monitoring with the patient’s obstetrician/gynecologist and consideration of early acyclovir.

1. Villalon-Gomez JM. Pityriasis Rosea: Diagnosis and Treatment. Am Fam Physician. 2018 Jan 1;97(1):38-44.

2. Corson EF, Luscombe HA. Coincidence of pityriasis rosea with pregnancy. AMA Arch Derm Syphilol. 1950 Oct;62(4):562-4.

3. Rebora A, Ciccarese G, Herzum A, Parodi A, Drago F. Pityriasis rosea and other infectious eruptions during pregnancy: Possible life-threatening health conditions for the fetus. Clin Dermatol. 2020 Jan-Feb;38(1):105-112.

4. Drago F, Broccolo F, Zaccaria E, Malnati M, Cocuzza C, Lusso P, Rebora A. Pregnancy outcome in patients with pityriasis rosea. J Am Acad Dermatol. 2008 May;58(5 Suppl 1):S78-83.

5. Drago F, Broccolo F, Javor S, Drago F, Rebora A, Parodi A. Evidence of human herpesvirus-6 and -7 reactivation in miscarrying women with pityriasis rosea. J Am Acad Dermatol. 2014 Jul;71(1):198-9.

6. Stashower J, Bruch K, Mosby A, Varghese JA, Rangel SM, Brodell RT, Zheng L, Flowers RH. Pregnancy Complications Associated with Pityriasis Rosea: A Multicenter Retrospective Study. J Am Acad Dermatol. 2021 Jan 7 Epub ahead of print

7. Alajmi A, Jfri A, Pehr K. Pityriasis Rosea: Risk and Treatment During Pregnancy. J Cutan Med Surg. 2020 Mar/Apr;24(2):207-208. doi: 10.1177/1203475420902049. PMID: 32208015.

8. Drago F, Ranieri E, Malaguti F, Battifoglio ML, Losi E, Reborn A. Human herpesvirus 7 in patients with pityriasis rosea. Dermatology. 1997;195(4):374-8.

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