Abstract
Atopic dermatitis and psoriasis are both common chronic inflammatory skin conditions that can significantly affect the quality of life for individuals affected by them. With the growing use of biologic agents, there have been remarkable clinical advancements in the treatment of these diseases. Interestingly, during biologic therapy for either condition, a phenomenon has emerged where treatment can paradoxically induce a transition to the phenotype of the other condition.We present two cases of immune drift phenomena caused by biologic agents for treating psoriasis and atopic dermatitis.The first one is a case of psoriasis lesion that developed in an old patient with AD who was treated with dupilumab for two months. The second one is a case of eczematoid lesion that developed in an adult patient with ankylosing spondylitis who was treated with Secukinumab for 1 year.