Pityriasis Rosea

para>Face and distal extremities are more often involved in children, and lesions may be more papular.

EPIDEMIOLOGY

Predominant age: 10 to 35 years, but occurs in all age groups
Predominant sex: male = female
- Some studies have shown a slight female preponderance.
No racial predominance

Incidence
Relatively common, but exact frequency is unknown.

ETIOLOGY AND PATHOPHYSIOLOGY

Unknown; may be a viral agent or an autoimmune disorder. Several studies have implicated the human herpesviruses (HHV), most commonly HHV-7, but other research has not confirmed this association. Case reports have also suggested an association with novel influenza A (H1N1) infection (1).
A similar rash has been reported with several drugs including gold injections, captopril, interferon, omeprazole, and bismuth.

Genetics
<5% of those affected give a positive family history.

DIAGNOSIS

HISTORY

The most common initial sign is a 2- to 10-cm salmon-colored patch or plaque known as the herald patch. The herald patch is present 40 " 76% of the time (2).
More widespread rash begins 7 to 14 days after the onset of the herald patch, although it may appear up to 3 months later.
Mild pruritus, rarely severe
Fever and malaise, rare

PHYSICAL EXAM

Salmon-colored to light-brown oval plaques with fine scales centrally and collarette of loose scales along borders

Lesions average 1 to 2 cm in diameter and usually spare face, hands, and feet in adults.
Lesions frequently are oriented along skin cleavage (Langer) lines in "Christmas tree " pattern.
Variant forms include purpuric, urticarial, and vesicular lesions, especially in children.

DIFFERENTIAL DIAGNOSIS

Secondary syphilis
Viral exanthems
Drug rashes
Psoriasis
Parapsoriasis
Eczema
Lichen planus
Tinea corporis

DIAGNOSTIC TESTS & INTERPRETATION

Initial Tests (lab, imaging)
No specific lab markers. Consider serology to rule out syphilis, if suspected.
Diagnostic Procedures/Other

Potassium hydroxide (KOH) preparation to distinguish disease from tinea corporis, especially early before multiple lesions are present.
Dermoscopy reveals a yellow background hue, dotted vessels, and peripheral scales (3).

Test Interpretation
Chronic inflammation with cytolytic degeneration of keratinocytes adjacent to Langerhans cells.

TREATMENT

GENERAL MEASURES

Symptomatic treatment
Topical antipruritics, as needed
Lukewarm oatmeal baths (not hot because heat can intensify itching)

MEDICATION

A Cochrane review updated in 2009 showed poor quality of evidence for most treatments of pityriasis rosea (4)[A].
Symptomatic treatment, as needed

First Line

Topical steroids to reduce itching, if needed
- Triamcinolone 0.1% cream
Oral antihistamines to reduce itching, if needed
- Diphenhydramine (Benadryl) 25 mg TID
- Chlorpheniramine 8 mg TID

Second Line

Erythromycin showed apparent benefit in one trial, although azithromycin failed to show significant benefit in another (5,6)[B].
High-dose acyclovir (800 mg 5 times per day for 7 to 14 days), used early in the disease course, also showed benefit (7)[C],(8)[B].

COMPLEMENTARY & ALTERNATIVE MEDICINE

Ultraviolet therapy has been used, but a controlled study found minimal benefit (9)[B].

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring
Return visit for reevaluation if lesions persist >8 to 10 weeks

PATIENT EDUCATION

Reassure patient about self-limited nature of condition.
Printed patient information available from American Academy of Dermatology: 708-330-0230

PROGNOSIS

Gradual resolution in 1 to 14 weeks (usually 2 to 6 weeks)

COMPLICATIONS

Secondary infection (e.g., impetigo)

REFERENCES

11 Mubki TF, Bin Dayel SA, Kadry R. A case of pityriasis rosea concurrent with the novel influenza A (H1N1) infection. Pediatr Dermatol. 2011;28(3):341 " 342.22 Chuh A, Lee A, Zawar V, et al. Pityriasis rosea " an update. Indian J Dermatol Venereol Leprol. 2005;71(5):311 " 315.33 Lallas A, Kyrgidis A, Tzellos TG, et al. Accuracy of dermoscopic criteria for the diagnosis of psoriasis, dermatitis, lichen planus and pityriasis rosea. Br J Dermatol. 2012;166(6):1198 " 1205.44 Chuh AA, Dofitas BL, Comisel GG, et al. Interventions for pityriasis rosea. Cochrane Database Syst Rev. 2007;(2):CD005068.55 Sharma PK, Yadav TP, Gautam RK, et al. Erythromycin in pityriasis rosea: a double-blind, placebo-controlled clinical trial. J Am Acad Dermatol. 2000;42(2 Pt 1):241 " 244.66 Amer A, Fischer H. Azithromycin does not cure pityriasis rosea. Pediatrics. 2006;117(5):1702 " 1705.77 Drago F, Vecchio F, Rebora A. Use of high-dose acyclovir in pityriasis rosea. J Am Acad Derm. 2006;54(1):82 " 85.88 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 " YC04.99 Leenutaphong V, Jiamton S. UVB phototherapy for pityriasis rosea: a bilateral comparison study. J Am Acad Dermatol. 1995;33(6):996 " 999.

ADDITIONAL READING

Chuh A, Chan H, Zawar V. Pityriasis rosea " evidence for and against an infectious aetiology. Epidemiol Infect. 2004;132(3):381 " 390.
Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. J Am Acad Dermatol. 2009;61(2):303 " 318.
Gonz ‘lez LM, Allen R, Janniger CK, et al. Pityriasis rosea: an important papulosquamous disorder. Int J Dermatol. 2005;44(9):757 " 764.

CODES

ICD10

L42 Pityriasis rosea

ICD9

696.3 Pityriasis rosea

SNOMED

Pityriasis rosea (disorder)

CLINICAL PEARLS

History of a herald patch preceding the generalized rash is helpful in the diagnosis of pityriasis rosea.
Treat symptomatically for itching, if needed.
No evidence supports aggressive treatment of this otherwise self-limiting condition, which usually resolves in 2 to 6 weeks.
High-dose acyclovir may hasten resolution.

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