A 16 year old boy presented with asymptomatic, multiple erythamatous annular lesions with a collarette of scales at periph-ery of the lesions present on the trunk. The most likely diagnosis is:

C i.e. Pityriasis rosea Pityriasis rosea is a self limiting disorderQ of unknown etiology, with a suspected association with Herpes virus 7 and 6Q. It presents with development of usually asymptomatic (i.e. no prodromal or constitutional system), sharply (well) demarcated, larger (2-6 cm), annular (oval-round), erythematousQ (red to brown) lesion k/a primary/herald/mother patch mostly located on trunk in children and young adults (10-35 yrs)( 2. Similar but smaller secondary eruptions appear in crops at interval of usually 2 weeks distributed along lines of cleavage in christmas (fir) tree appearanceQ. Lesions demonstrate fine (cigarette paper) collarette of scaleQ just inside the peripheray of plaque.