AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Pityriasis rosea, a rash first described by Gilbert in the 19th century, is a common type of papulosquamous skin eruption that is typically acute in onset and self-limiting. It has a distinctive morphology and clinical course and a predilection for young adults. Other types of similar skin eruptions include lichen planus, psoriasis, eczema, and pityriasis rubra pilaris. The rash of pityriasis rosea is scaly in appearance and consists of papules and, sometimes, plaques. The rash is usually short-lived and only requires symptomatic treatment. It evolves rapidly and usually begins with the well-known herald patch.

Frequency

United States

Pityriasis rosea is very common in the general population, and most cases occur in the spring and winter in temperate climates. The estimated frequency of pityriasis rosea in the United States is approximately 0.13% in females and 0.14% in males.

International

An increased frequency is reported in certain countries (eg, Uganda).

Mortality/Morbidity

Pityriasis is a self-limiting illness with very little morbidity. It follows a benign course in most patients, and complete resolution of symptoms is the rule. However, some cases of severe eczematous or drug-induced rashes may be protracted. These cases are known as pityriasis rosea perstans.

Race

Pityriasis has no predilection for any race.

Sex

Incidence of rash development is slightly higher in females than in males.

Age

Approximately 87-90% of cases occur in people aged 10-40 years. Pityriasis is rare in the very young population and the older population.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Patients may report a history of nonspecific symptoms (eg, malaise, nausea, fever) that precede the development of the rash.
• Obtain a detailed dermatologic history in all patients.
• • Ask patients about prior dermatologic diseases and their manifestations.
  • Elicit symptoms of the presenting rash (eg, pruritus, pain).
• When pertinent, obtain a history of sexually transmitted diseases.
• Record travel history, occupational exposure, and drug exposure in the medical record.
• Ask patients about ill contacts.

Physical

• The initial skin lesion of pityriasis is a pink (rosea) oval patch approximately 3-6 cm in diameter that can occur anywhere on the body, although it is most commonly located on the back. This is referred to as the herald patch.
• • The herald patch has a scale (pityriasis) that resembles a collarette toward the periphery.
  • The patch is something of a dermatologic enigma because it does not occur in any other known skin disease. The earliest stages of the patch may manifest as pink papules that can be mistaken for other lesions (eg, insect bites).
• A few days later, the initial patch is followed by a rash of similar but smaller lesions.
• • Secondary eruptions appear in crops at intervals of a few days and reach a maximum in about 10 days.
  • The rash typically follows the cleavage lines of the skin, resulting in a Christmas tree–type pattern.
  • The secondary rash is generally distributed on the back, chest, abdomen, arms, and thighs.
  • The rash can last up to 6-8 weeks before fading.
• Lesions are typically symmetric and are not preceded by systemic symptoms.
• Pruritus appears to be the predominant symptom but can be absent in as many as 25% of cases.
• Individuals with dark skin can have a postinflammatory hyperpigmentation that may take a few months to heal. Both hypopigmentation and hyperpigmentation can follow the rash.
• The following atypical features occasionally occur:
• • Herald patch is sometimes absent (present in 50-90% of cases).
  • Skin eruptions may be florid.
  • Lesions may be few, large, and in a particular body region (eg, axilla). In adults, this is known as pityriasis circinata et marginata of Vidal.
  • Rash may be located in areas not usually affected by pityriasis; this is known as inverse pityriasis rosea.
  • Pityriasis may occur in sun-spared areas such as the breast and the axilla.
  • Lesions are sometimes papular, vesicular, or purpuric.

Causes

• An infectious etiology for pityriasis rosea has been sought for many years.
• It was once thought that a viral agent might be the precipitant. Over the past few years, there has been considerable interest in human herpesvirus 7 as a possible etiologic agent. Investigative studies have failed to link this virus, as well as others, to the well-known rash of pityriasis rosea.
• Some investigators believe that a fungal infection is more likely.
• Thus far, the search for an infectious agent has been unsuccessful.
• The incidence of the rash among dermatologists is 3-4 times that of other physicians.
• Recurrences are generally regarded as rare and are thought by some to indicate a lasting immunity when they do occur.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Pityriasis versicolor (tinea versicolor)
Guttate psoriasis
Seborrheic eczema
Parapsoriasis
Drug eruptions/toxins (eg, arsenic, bismuth, barbiturates, gold, captopril, organic mercurials)
Pityriasis lichenoides (extremity lesions)
Pityriasis rubra pilaris
Tinea
Lichen planus
Seborrheic dermatitis
Nummular eczema
Pityriasis alba (on the face, arms, and thorax in children and young adults)

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• In most cases of pityriasis rosea, laboratory studies are unnecessary.
• Syphilis should be strongly considered in the differential diagnosis.
• Generally, order a rapid plasma reagin (RPR) test, and ensure that the patient receives follow-up care.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• In most cases, pityriasis rosea is a self-limited disorder, and treatment is not necessary in uncomplicated cases.
• The rash usually disappears in a few weeks.
• Patients should avoid irritants such as wool, certain irritant soaps, perfumes, and household products.
• Pruritus is commonly associated with the rash and can be treated conservatively with calamine lotion or oral antihistamine therapy.
• If the rash is severe, topical steroids can be applied.
• • Remember that steroids alleviate the pruritus, but they do not modify the eruption.
  • Cases of severe exacerbations have been reported in association with oral steroid use.

Consultations

In some instances, obtaining an infectious disease or dermatology consultation is warranted, especially in patients with atypical cases, comorbid conditions, solid organ transplants, or hematopoietic stem cell transplants.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Drug therapy for pityriasis rosea primarily consists of symptomatic treatment of pruritus. Oral antihistamines and topical corticosteroids can be used as needed. For patients in whom superficial tinea infection is a concern or possibility, topical antifungal therapy can be instituted.

Drug Category: Antihistamines

Consider oral antihistamine therapy in patients with pruritus. May control itching by blocking effects of endogenously released histamine.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Patients should have follow-up care to ensure that the rash is improving. Further evaluation of other etiologies may be warranted if the rash worsens or fails to improve or if the patient develops other signs or symptoms.

Complications

• Complications are extremely rare but can include superinfection of the rash in vesicular pityriasis and changes in pigmentation.

Prognosis

• Prognosis is generally very good.

Patient Education

• Patients should receive education regarding the noninfectious nature of the rash and the time course expected before resolution occurs.
• For excellent patient education resources, visit eMedicine's Skin, Hair, and Nails Center. Also, see eMedicine's patient education article Eczema.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Until proven otherwise, consider syphilis to be present in a patient who has a pityriasis-type rash and risk factors for sexually transmitted diseases (eg, intravenous drug use, HIV, promiscuity).
• Rarely, herpes zoster infection is confused with the vesicular variant of pityriasis rosea.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• 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].
• Cohen EL. Pityriasis rosea. Br J Dermatol. Oct 1967;79(10):533-7. [Medline].
• Harman M, Aytekin S, Akdeniz S, Inaloz HS. An epidemiological study of pityriasis rosea in the Eastern Anatolia. Eur J Epidemiol. Jul 1998;14(5):495-7. [Medline].
• Hartley AH. Pityriasis rosea. Pediatr Rev. Aug 1999;20(8):266-9, quiz 270. [Medline].
• Kempf W, Adams V, Kleinhans M, et al. Pityriasis rosea is not associated with human herpesvirus 7. Arch Dermatol. Sep 1999;135(9):1070-2. [Medline].
• Parsons JM. Management of toxic epidermal necrolysis. Cutis. Oct 1985;36(4):305-7, 310-1. [Medline].
• Tay YK, Goh CL. One-year review of pityriasis rosea at the National Skin Centre, Singapore. Ann Acad Med Singapore. Nov 1999;28(6):829-31. [Medline].
• Wyndham M. Pityriasis. Practitioner. Jun 1997;241(1575):358. [Medline].

Article Last Updated: Aug 24, 2005