How is dx of psoriasis?

• The diagnosis of psoriasis is clinical • Skin biopsy is only indicated when there is a diagnostic doubt for atypical lesions • Classical presentation: Plaque-Psoriasis • More often than not, these lesions are multiple and symmetrical, sometimes diffuse • The size of the lesions is variable: plaque psoriasis; nummular psoriasis • Elective locations (bastion areas): Areas exposed to friction and physical trauma: elbows (and cubital edge of the forearm) knees, legs, lower back sagging region, scalp , nails, palms and soles • Usually respect for the face