eMedicine Specialties > Emergency Medicine > Dermatology

Pityriasis Rosea

Author: Richard Lichenstein, MD, Associate Professor, Pediatric Emergency Department, University of Maryland School of Medicine
Contributor Information and Disclosures

Updated: Dec 8, 2009

Introduction

Background

Pityriasis rosea (PR) is an acute and characteristic exanthem that has been described for more than 2 centuries. Initially, a primary plaque, called a herald patch, is seen (as is demonstrated in the image below).

Herald patch. Courtesy of the Drexel Department o...

Herald patch. Courtesy of the Drexel Department of Dermatology slide collection.

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Herald patch. Courtesy of the Drexel Department o...

Herald patch. Courtesy of the Drexel Department of Dermatology slide collection.


The herald patch is followed by a distinctive, generalized rash 1-2 weeks later. The rash lasts approximately 2-6 weeks.

Pathophysiology

A recent study noted a lack of natural killer (NK) cell and B-cell activity in pityriasis rosea lesions, suggesting a predominantly T-cell mediated immunity in the development of the condition.1

The primary plaque is seen on the skin in 50-90% of cases a week or more before the onset of the eruption of smaller lesions. This secondary eruption occurs 2-21 days later in crops following the lines of cleavage of the skin. On the back, this eruption produces a "Christmas tree" pattern.

Christmas tree distribution of lesions on the tru...

Christmas tree distribution of lesions on the trunk. Courtesy of the Drexel Department of Dermatology slide collection.

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Christmas tree distribution of lesions on the tru...

Christmas tree distribution of lesions on the trunk. Courtesy of the Drexel Department of Dermatology slide collection.


Frequency

United States

The overall prevalence of pityriasis rosea has been calculated to be 0.13% in men and 0.14% in women. The prevalence reported at dermatologic centers is 0.3-3%.

International

An increase in the prevalence of pityriasis rosea has been reported in Uganda. No change in the prevalence of pityriasis rosea has been reported in Sweden. It has also been seen in the United Kingdom, Nigeria, Sudan, Brazil, Lagos, Singapore, Turkey, Kuwait, and Hong Kong.

Mortality/Morbidity

Pityriasis rosea is a self-limited, benign illness.

Sex

Pityriasis rosea is reported to occur equally in the two sexes or slightly more often in females. The ratio of men to women varies from 1:1.43.

Age

Pityriasis rosea is most common in children and young adults. Prevalence of pityriasis rosea rises during childhood and is most common in persons aged 15-40 years. Pityriasis rosea is rare in infants and in elderly persons; however, it has been reported in infants as young as 3 months.

Clinical

History

  • Pityriasis rosea (PR) may have prodromal symptoms (eg, malaise, nausea, anorexia, fever, joint pain, lymph node swelling, headache) that may precede the appearance of the herald patch.
  • Pruritus, which may be intense, is present in 75% of cases.
  • Ask the patient whether this is the first episode or a recurrence.

Physical

  • The herald patch measures 1-2 cm in diameter. The patch is characterized as oval or round with a central, wrinkled, salmon-colored area and a dark red peripheral zone. The areas are separated by a collarette of fine scales. The herald patch is usually located on the trunk but can be seen on the neck or extremities.
  • The secondary eruption appears at its maximum in about 10 days.
    • The secondary eruption is symmetric and localized, predominantly to the trunk and adjacent areas of the neck and extremities.
    • Involvement is maximal over the abdomen and anterior and dorsal surfaces of the thorax.
    • The secondary lesions appear as the primary patch in miniature, with the two red zones separated by the scaling ring. They are distributed in a Christmas tree pattern with their long axes following the lines of cleavage of the skin. In children under the age of 5 years, papular pityriasis rosea may be seen with a similar distribution.
  • In atypical pityriasis rosea (20% of patients), the herald patch may be missing or confluent with other lesions.
    • The distribution of the rash may be peripheral, and facial involvement may be seen in children. Involvement of the axilla and groin (inverse variant) can also be seen.
    • The lesions of pityriasis rosea may be large (pityriasis rosea gigantea), urticarial (pityriasis rosea urticata), vesicular, pustular, purpuric, and erythema multiforme –like.
  • Hypopigmentary and hyperpigmentary skin changes may follow the inflammatory stage. In patients with black skin, hyperpigmentation is more common.
  • Black children have been shown to have more facial involvement (30%) and scalp involvement (8%) than white children. Approximately one third of black children have papular lesions, and 48% have residual hyperpigmentation.2
  • Oral lesions of various types have been reported with pityriasis rosea, including erythematous plaques, hemorrhagic puncta, and ulcers.

Causes

  • Pityriasis rosea is similar to infectious exanthems in that it occurs in clusters among contacts, has a seasonal predilection to spring and autumn, and has a low rate of recurrence (3%).
  • No bacteria, virus, or fungus has been isolated as a definite causal agent, although human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) may play a role.3,4
  • Drugs such as bismuth, barbiturates, captopril, gold, organic mercurials, methoxypromazine, metronidazole, D-penicillamine, isotretinoin, tripelennamine hydrochloride, ketotifen, and salvarsan have been implicated in causing drug-induced pityriasis rosea.
  • Atopy, seborrheic dermatitis, acne vulgaris, and dandruff are more common in patients with pityriasis rosea than in control subjects.

More on Pityriasis Rosea

Overview: Pityriasis Rosea
Differential Diagnoses & Workup: Pityriasis Rosea
Treatment & Medication: Pityriasis Rosea
Follow-up: Pityriasis Rosea
Multimedia: Pityriasis Rosea
References
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References

  1. Neoh CY, Tan AW, Mohamed K, Sun YJ, Tan SH. Characterization of the inflammatory cell infiltrate in herald patches and fully developed eruptions of pityriasis rosea. Clin Exp Dermatol. Jul 29 2009;[Medline].

  2. Amer A, Fischer H, Li X. The natural history of pityriasis rosea in black American children: how correct is the "classic" description?. Arch Pediatr Adolesc Med. May 2007;161(5):503-6. [Medline].

  3. Drago F, Ranieri E, Malaguti F. Human herpesvirus 7 in patients with pityriasis rosea. Electron microscopy investigations and polymerase chain reaction in mononuclear cells, plasma and skin. Dermatology. 1997;195(4):374-8. [Medline].

  4. Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol. Aug 2009;61(2):303-18. [Medline].

  5. Drago F, Rebora A. Treatments for pityriasis rosea. Skin Therapy Lett. Mar 2009;14(3):6-7. [Medline].

  6. Sharma PK, Yadav TP, Gautam RK. Erythromycin in pityriasis rosea: A double-blind, placebo-controlled clinical trial. J Am Acad Dermatol. Feb 2000;42(2 Pt 1):241-4. [Medline].

  7. [Best Evidence] Amer A, Fischer H. Azithromycin does not cure pityriasis rosea. Pediatrics. May 2006;117(5):1702-5. [Medline].

  8. Stulberg DL, Wolfrey J. Pityriasis rosea. Am Fam Physician. Jan 1 2004;69(1):87-91. [Medline].

  9. Drago F, Vecchio F, Rebora A. Use of high-dose acyclovir in pityriasis rosea. J Am Acad Dermatol. Jan 2006;54(1):82-5. [Medline].

  10. [Guideline] Finnish Medical Society Duodecim. Syphilis. In: EBM Guidelines. Evidence-Based Medicine [Internet]. Helsinki, Finland: Wiley Interscience. John Wiley & Sons; 2008 Jun 6. [Full Text].

  11. Chuh A, Chan H, Zawar V. Pityriasis rosea--evidence for and against an infectious aetiology. Epidemiol Infect. Jun 2004;132(3):381-90. [Medline].

  12. Chuh A, Lee A, Zawar V. Pityriasis rosea--an update. Indian J Dermatol Venereol Leprol. Sep-Oct 2005;71(5):311-5. [Medline].

  13. Coustou D, Leaute-Labreze C, Bioulac-Sage P, et al. Asymmetric periflexural exanthem of childhood: a clinical, pathologic, and epidemiologic prospective study. Arch Dermatol. Jul 1999;135(7):799-803. [Medline].

  14. Hartley AH. Pityriasis rosea. Pediatr Rev. Aug 1999;20(8):266-9, quiz 270. [Medline].

  15. Horio T. Skin disorders that improve by exposure to sunlight. Clin Dermatol. Jan-Feb 1998;16(1):59-65. [Medline].

  16. Kay MH, Rapini RP, Fritz KA. Oral lesions in pityriasis rosea. Arch Dermatol. Nov 1985;121(11):1449-51. [Medline].

  17. Kempf W, Burg G. Pityriasis rosea--a virus-induced skin disease? An update. Arch Virol. 2000;145(8):1509-20. [Medline].

  18. Nanda A, Al-Hasawi F, Alsaleh QA. A prospective survey of pediatric dermatology clinic patients in Kuwait: an analysis of 10,000 cases. Pediatr Dermatol. Jan-Feb 1999;16(1):6-11. [Medline].

  19. Pomeranz AJ, Fairley JA. The systematic evaluation of the skin in children. Pediatr Clin North Am. Feb 1998;45(1):49-63. [Medline].

  20. Scott LA, Stone MS. Viral exanthems. Dermatol Online J. Aug 9 2003;9(3):4. [Full Text].

  21. Wyndham M. Pityriasis. Practitioner. Jun 1997;241(1575):358. [Medline].

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Further Reading

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Keywords

pityriasis rosea, PR, pityriasis rosea gigantica, pityriasis rosea urticata, papular PR, atypical PR, drug-induced PR, keratosis, vesicular PR, herald patch, rash, pruritus, exanthem, treatment, symptoms

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Contributor Information and Disclosures

Author

Richard Lichenstein, MD, Associate Professor, Pediatric Emergency Department, University of Maryland School of Medicine
Richard Lichenstein, MD is a member of the following medical societies: American Academy of Pediatrics and American Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Jerry Balentine, DO, Professor of Emergency Medicine, New York College of Osteopathic Medicine; Executive Vice President, Chief Medical Officer, Attending Physician in Department of Emergency Medicine, St. Barnabas Hospital
Jerry Balentine, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American College of Physician Executives, American Osteopathic Association, and New York Academy of Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center; Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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