A 7-year-old girl develops multiple oval, salmon-colored, scaly papules on the trunk following a herald patch. The lesions follow skin lines in a 'Christmas tree' pattern. She had a mild upper respiratory illness 2 weeks ago. Which statement about the etiology is most accurate?

• A Caused by Pityrosporon (Malassezia) overgrowth requiring antifungal treatment
• B Associated with HHV-6 or HHV-7 reactivation; self-limiting over 6–8 weeks ✓
• C Caused by Streptococcus pyogenes requiring penicillin
• D Drug reaction to NSAIDs commonly prescribed for viral URTI

Explanation

Pityriasis rosea (PR) follows a characteristic pattern: a herald patch (larger oval lesion) 1–2 weeks before the generalized eruption, followed by 'fir tree' or Christmas tree distribution of lesions along Langer's lines on the trunk. It is strongly associated with HHV-6 and HHV-7 reactivation (not primary infection), typically following an URTI. It is self-limiting, resolving spontaneously in 6–8 weeks. Treatment is symptomatic (antihistamines for itch, emollients). Antifungals are ineffective. Syphilis can mimic PR (secondary syphilis) and must be excluded in adolescents.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.