Multiple erythematous annular lesions with peripheral collorette of scales arranged predominantly on trunk are seen in –

PITYRIASIS The 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 Pitriasis Pityriasis rosea Children and young adults Erythmatous annular plaque → Mother patch (Herald patch) Mainly involves Trunk. Christmas tree or Fir tree configration Collarette scales (cigar paper scale) Self limiting course Pityriasis rubra pilaris Two peaks → 5-10 years and 40-60 years Elythmatous (orange to pink), follicular, scaly plaques Characteristic presence of distinct island of normal skin Involvement of trunk with cranio caudal distribution Nutmeg papules on knuckles Thickening of palms (Palmer thickening) & soles (keratoden-nic sandals) Pityriasis lichenoides 1)   Pityriasis lichenoides et variolifermis acuta Constitutional symptoms; fever, arthralgia Multiple erythmatous & edematous papules often surmounted by vesicles Lesions heal with hyperpigmented scar  Trunk and flexures of arm 2) Pityriasis lichenoides chronica Successive crops of red-brown papules which are surmounted by a central adherent mica like scales Lesions heal with hypopigmentation Trunk and proximal part of extremities Pityriasis alba Children (6-12 years) Hypopigmented macule on face Presence of fine scales Pityriasis versicolor Young adults Hypopigmented macule Fine scales → Furfuraceous or rice powder like scales Involvement of Trunk and shoulder (chest & backs) Note - Pityriasis Rosea, Pityriasis rubra pilaris and pityriasis lichenoides are papulosquamous lesions, whereas pityriasis versicolor and pityriasis alba are not papulosquamous lesions.