"De Novo" Psoriasis and Relapse of Psoriasis Induced by Dupilumab: Three New Cases and Review of the Literature.

Atopic dermatitis and psoriasis are traditionally considered diseases that cannot coexist, since they are described as the result of the activation of opposing inflammatory pathways. However, this belief has been debunked, and numerous cases of psoriasis induced by dupilumab, a biologic treatment for atopic dermatitis, have been reported. We report three cases of dupilumab-induced psoriasis and we present a literature review including cases of "de novo" psoriasis and of the relapse of psoriasis that occurred during treatment with dupilumab. In total, 39 publications met the inclusion criteria, including 112 AD patients, 101 of whom developed "de novo" psoriasis, and 11 with a flare of pre-existent psoriasis. In the first group, patients more frequently developed plaque psoriasis on the scalp and extremities, after an average latency period from the initiation of dupilumab of 5 months. In the second group, the incidence of dupilumab-induced relapses of psoriasis was 43%, after an average of 4 months since the first administration. The most common psoriasis type was plaque psoriasis, with the involvement of the scalp and upper extremities. Dupilumab was interrupted in 38% of patients with "de novo" psoriasis and in 50% of relapsed patients, leading, in most cases, to an improvement of psoriasis. In conclusion, atopic dermatitis and psoriasis can definitely co-exist, and biologic drugs used to treat the former can promote the latter. It is thus crucial to perform a careful personal and familiar anamnesis before prescribing any biologic treatment. Moreover, a study of cytokine expression and blood proteomic markers could be considered in these patients.