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What is A 16-year-old boy presented with asymptomatic, multiple, erythematous, annular lesions with a collarette of scales at the periphery of the lesions present on the trunk. The most likely diagnosis is: and explain in detail?
Lesions predominantly localized to the trunk and their erythematous nature with other features of pityriasis lead to diagnosis of pityriasis rosea. Ref: Anthony Du Vivier, Phillip H. McKee, Chapter 6, "Pityriasis Rosea and Pityriasis Rubra Pilaris", In the book, "Atlas of Clinical Dermatology", Elsivier Publication, 2002, 3rd Edition, Spain, Page 87