The 1st sign of pityriasis rosea (PR) is usually a well-demarcated, salmon-colored macule that evolves into a larger patch (1-4 cm) with peripheral scaling (“herald patch”). Over 1 to 2 weeks, generalized, bilateral, and symmetric macules and plaques appear along skin cleavage lines (termed “Christmas tree” pattern). The macules have a peripheral collarette of fine scaling. Most will have severe itching associated with the generalized eruption. The lesions slowly resolve over 6 to 8 weeks. Atypical presentations in children include inverse PR (presentation on the face, axillae, and/or inguinal areas) and papular PR (peripheral scaling papules with central, hyperpigmented plaques). A viral etiology is postulated due to seasonal variation and case clustering.
Pityriasis Rosea Herald Patch. The herald patch of PR, a well-demarcated salmon-colored macule with scales, frequently precedes the generalized phase by 1 to 2 weeks. (Photo contributor: Lawrence B. Stack, MD.)
Management and Disposition
PR is both benign and self-limited. Pruritus can be treated with oral antihistamines, topical steroids, and oatmeal baths.
Patients often will not describe the herald patch unless specifically asked.
In patients with risk factors for syphilis and HIV, appropriate screening tests should be performed.
Patients should be warned of the possible extended course of PR and given appropriate antihistamines and follow-up.
Atypical presentations are seen in dark-skinned individuals and children; often, lesions present in the axilla and groin.
Pityriasis Rosea. An exanthematous, papulosquamous eruption, with the long axis of the oval papules following the lines of cleavage in a Christmas tree–like eruption. (Photo contributor: David Effron, MD.)