<prompt> Multiple erythematous annular lesions with peripheral collorette of scales arranged predominantly on trunk are seen inPityriasis vesicularPytiriasis rubra pilarisPityriasis roseaPityriasis lichennoides chronica  <response>: PITYRIASISThe term pityriasis is used to describe skin condition in which the scale appears similar to bran. So, any skin disease with pityriasis in its name will be scaly.Differential diagnosis of different PitriasisPityriasis roseaChildren and young adultsErythmatous annular plaque Mother patch Herald patchMainly involves Trunk.Christmas tree or Fir tree configrationCollarette scales cigar paper scaleSelf limiting coursePityriasis rubra pilarisTwo peaks 5-10 years and 40-60 yearsElythmatous orange to pink, follicular, scaly plaquesCharacteristic presence of distinct island of normal skinInvolvement of trunk with cranio caudal distributionNutmeg papules on knucklesThickening of palms Palmer thickening soles keratoden-nic sandalsPityriasis lichenoides1 Pityriasis lichenoides et variolifermis acutaConstitutional symptoms; fever, arthralgiaMultiple erythmatous edematous papules often surmounted by vesiclesLesions heal with hyperpigmented scar Trunk and flexures of arm2 Pityriasis lichenoides chronicaSuccessive crops of red-brown papules which are surmounted by a central adherent mica like scalesLesions heal with hypopigmentationTrunk and proximal part of extremitiesPityriasis albaChildren 6-12 yearsHypopigmented macule on facePresence of fine scalesPityriasis versicolorYoung adultsHypopigmented maculeFine scales Furfuraceous or rice powder like scalesInvolvement of Trunk and shoulder chest backsNote - Pityriasis Rosea, Pityriasis rubra pilaris and pityriasis lichenoides are papulosquamous lesions, whereas pityriasis versicolor and pityriasis alba are not papulosquamous lesions. 