eMedicine Specialties > Dermatology > Papulosquamous Diseases

Pityriasis Rosea: Differential Diagnoses & Workup

Author: Robert A Allen, MD, Staff Physician, Department of Dermatology, Drexel University College of Medicine-Hahnemann Hospital
Coauthor(s): Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Contributor Information and Disclosures

Updated: Feb 13, 2009

Differential Diagnoses

Erythema Dyschromicum Perstans
Psoriasis, Guttate
Lichen Planus
Seborrheic Dermatitis
Nummular Dermatitis
Syphilis
Pityriasis Lichenoides
Tinea Corporis

Other Problems to Be Considered

Primary human immunodeficiency viral infection
Viral exanthems

Workup

Laboratory Studies

  • One must be careful to rule out syphilis.
    • A screening rapid plasma reagin (RPR) test or a VDRL test should be ordered for appropriate individuals.
    • One should be aware of the prozone phenomenon seen in secondary syphilis and request titration of the RPR test.
    • An HIV test should also be considered in these patients.
  • Other laboratory tests are usually normal and, therefore, unhelpful. Changes in the white blood cell count and differential, as well as increases in erythrocyte sedimentation rate, total serum protein level, globulin level, and albumin level, are rarely reported.

Histologic Findings

A biopsy specimen is helpful to confirm the diagnosis, especially in atypical cases. It shows superficial perivascular dermatitis (see Media File 3). Focal parakeratosis in mounds, hyperplasia, and focal spongiosis are observed in the epidermis. The epidermis may show exocytosis of lymphocytes, variable spongiosis, mild acanthosis, and a thinned granular layer. In the dermis, extravasated red blood cells are a helpful finding along with a perivascular infiltrate of lymphocytes, histiocytes, and eosinophils. A number of monocytes are also commonly present.

The herald patch has similar features but has a deeper infiltrate and more acanthosis owing to its chronicity. Such variations as dyskeratotic cells in the epidermis, multinuclear giant cells, and focal acantholytic dysfunction have been observed. These features may closely resemble erythema annulare centrifugum, guttate psoriasis, superficial gyrate erythema, and small plaque parapsoriasis.

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. Chuh AA, Chan PK, Lee A. The detection of human herpesvirus-8 DNA in plasma and peripheral blood mononuclear cells in adult patients with pityriasis rosea by polymerase chain reaction. J Eur Acad Dermatol Venereol. Jul 2006;20(6):667-71. [Medline].

  2. Drago F, Ranieri E, Malaguti F, Battifoglio ML, Losi E, Rebora A. 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].

  3. Broccolo F, Drago F, Careddu AM, et al. Additional evidence that pityriasis rosea is associated with reactivation of human herpesvirus-6 and -7. J Invest Dermatol. Jun 2005;124(6):1234-40. [Medline].

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

  5. Chuang TY, Ilstrup DM, Perry HO, Kurland LT. Pityriasis rosea in Rochester, Minnesota, 1969 to 1978. J Am Acad Dermatol. Jul 1982;7(1):80-9. [Medline].

  6. 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].

  7. Arndt KA, Paul BS, Stern RS, Parrish JA. Treatment of pityriasis rosea with UV radiation. Arch Dermatol. May 1983;119(5):381-2. [Medline].

  8. Leenutaphong V, Jiamton S. UVB phototherapy for pityriasis rosea: a bilateral comparison study. J Am Acad Dermatol. Dec 1995;33(6):996-9. [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. Rasi A, Tajziehchi L, Savabi-Nasab S. Oral erythromycin is ineffective in the treatment of pityriasis rosea. J Drugs Dermatol. Jan 2008;7(1):35-8. [Medline].

  11. Ackerman AB. Pityriasis rosea. In: Ackerman AB, ed. Histiologic Diagnosis of Inflammatory Skin Disease: A Method by Pattern Analysis. Philadelphia, Pa: Lea & Febiger; 1978.

  12. Bjornberg A, Hellgren L. Pityriasis rosea. A statistical, clinical, and laboratory investigation of 826 patients and matched healthy controls. Acta Derm Venereol Suppl (Stockh). 1962;42(Suppl 50):1-68. [Medline].

  13. Bjornberg A, Tegner E. Pityriasis rosea. In: Freedberg IM, Eisen AZ, Wolff K, et al, eds. Dermatology in General Medicine. 5th ed. New York, NY: McGraw-Hill; 1999:541-6.

  14. Miljkovic J, Bercic M, Belic M. Pityriasis rosea with unusual papulovesicular presentation. Acta Derm Venerol. 1996;5:61-3.

  15. Parsons JM. Pityriasis rosea update: 1986. J Am Acad Dermatol. Aug 1986;15(2 Pt 1):159-67. [Medline].

  16. Sezer E, Saracoglu ZN, Urer SM, Bildirici K, Sabuncu I. Purpuric pityriasis rosea. Int J Dermatol. Feb 2003;42(2):138-40. [Medline].

  17. Toussant S, Kareino H. Pityriasis rosea. In: Elder D, Elenitsas R, Jaworsky C, et al, eds. Lever's Histopathology of the Skin. 8th ed. Philadelphia, Pa: Lippincott-Raven; 1997:164-5.

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Further Reading

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Keywords

pityriasis rosea benign papulosquamous disease, herald spot, herald patch, picornavirus, human herpesvirus-6, HHV-6, human herpesvirus-7, HHV-7

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Contributor Information and Disclosures

Author

Robert A Allen, MD, Staff Physician, Department of Dermatology, Drexel University College of Medicine-Hahnemann Hospital
Robert A Allen, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, and American Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, and Sigma Xi
Disclosure: Nothing to disclose.

Medical Editor

Mark G Lebwohl, MD, Chairman, Department of Dermatology, Mount Sinai School of Medicine
Mark G Lebwohl, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Abbott Laboratories Honoraria Consulting; Actelion Honoraria Consulting; Amgen Honoraria Consulting; Astellas Honoraria Consulting; Basilea Honoraria Consulting; Briston-Myers Squibb Honoraria Consulting; Celtic Pharma  Other; Centocor Honoraria Consulting; Chattem Honoraria Other; DermiPsor Honoraria Consulting

Pharmacy Editor

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA
Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Association of Military Dermatologists, Texas Dermatological Society, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Jeffrey Meffert, MD, Assistant Clinical Professor of Dermatology, University of Texas Health Science Center-San Antonio
Jeffrey Meffert, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, Association of Military Dermatologists, and Texas Dermatological Society
Disclosure: Nothing to disclose.

CME Editor

Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University
Catherine Quirk, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Dermatology
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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