<prompt> 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:Pityriasis versicolorPityriasis albaPirityasis roseaPityriasis rubra pilaris  <response>: 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 