Pityriasis rosea most commonly occurs between ages 10 and 35. It affects women more often. The cause of pityriasis rosea may be viral infection (some research has implicated human herpesviruses 6, 7, and 8). Drugs may cause a pityriasis rosea–like reaction.
Symptoms and Signs of Pityriasis Rosea
The condition classically begins with a single, primary, 2- to 10-cm herald patch that appears on the trunk or proximal limbs. A general centripetal eruption of 0.5- to 2-cm rose- or fawn-colored oval papules and plaques follows within 7 to 14 days. The lesions have a scaly, slightly raised border (collarette) and resemble ringworm (tinea corporis Tinea Corporis (Body Ringworm) Tinea corporis is a dermatophyte infection of the face, trunk, and extremities. Diagnosis is by clinical appearance and by examination of skin scrapings on potassium hydroxide wet mount. Treatment... read more 
). Most patients itch, occasionally severely. Papules may dominate with little or no scaling in children and pregnant women. The rose or fawn color is not as evident in patients with darker skin; children more commonly have inverse pityriasis rosea (lesions in the axillae or groin that spread centrifugally).
Initially, most people develop one large scaly patch (herald patch; arrow), and within 1 to 2 weeks, smaller pink patches can occur on the trunk, arms, and legs.
Image courtesy of the Public Health Image Library of the Centers for Disease Control and Prevention.
Pityriasis rosea is characterized by an initial 2- to 10-cm herald patch followed by centripetal eruption of oval papules and plaques with a slightly raised border, typically appearing along skin lines.
Image provided by Thomas Habif, MD.
This image shows erythematous and violaceous, ovoid, scaly papules coalescing into patches on the head and torso of a patient with pityriasis rosea.
Image courtesy of Karen McKoy, MD.
This image shows violaceous, scaly plaques on the back and arms of a patient with pityriasis rosea. Patches that appear more pink in patients with lighter skin appear violaceous and/or hyperpigmented in patients with darker skin.
Image courtesy of Karen McKoy, MD.
This photo shows atypical (inverse) pityriasis rosea characterized by oval scaly plaques in the inguinal creases.
Image provided by E. Laurie Tolman, MD.
Classically, lesions orient along skin lines, giving pityriasis rosea a Christmas tree–like distribution when multiple lesions appear on the back. A prodrome of malaise, headache, and sometimes arthralgia precedes the lesions in a minority of patients.
Diagnosis of Pityriasis Rosea
Clinical evaluation
Diagnosis of pityriasis rosea is based on clinical appearance and distribution.
Differential diagnosis includes
Pityriasis lichenoides chronica
Serologic testing for syphilis Diagnostic tests for syphilis Syphilis is caused by the spirochete Treponema pallidum and is characterized by 3 sequential symptomatic stages separated by periods of asymptomatic latent infection. Common manifestations... read more 
is indicated when the palms or soles are affected, when a herald patch is not seen, or when lesions occur in an unusual sequence or distribution.
Treatment of Pityriasis Rosea
Antipruritic therapy
No specific treatment is necessary because the eruption usually remits within 5 weeks and recurrence is rare.
Artificial or natural sunlight may hasten resolution.
Antipruritic therapy such as topical corticosteroids, oral antihistamines, or topical measures may be used as needed.
Some data suggest that acyclovir 800 mg orally 5 times a day for 7 days may be helpful in patients who present early and have widespread disease, or present with flu-like symptoms. Of note, pityriasis rosea during pregnancy (especially during the first 15 weeks of gestation) is associated with premature birth or fetal demise. Pregnant women should be offered acyclovir; however, antiviral therapy has not proved to reduce obstetric complications.
Key Points
Pityriasis rosea is a self-limited, inflammatory disorder of the skin possibly caused by human herpesvirus types 6, 7, or 8 or drugs.
An initial 2- to 10-cm herald patch is followed by centripetal eruption of oval papules and plaques with a slightly raised and scaly border, typically appearing along skin lines.
Diagnose based on clinical appearance and distribution.
Treat with antipruritic drugs as needed and possibly topical corticosteroids and/or sunlight.
Pityriasis rosea during the first 15 weeks of pregnancy is associated with premature birth or fetal demise.
Pregnant women should be offered antiviral therapy, even though this has not proved to reduce obstetric complications.
Drugs Mentioned In This Article
| Drug Name | Select Trade |
|---|---|
acyclovir |
SITAVIG, Zovirax, Zovirax Cream, Zovirax Ointment, Zovirax Powder, Zovirax Suspension |
