Dupilumab-Induced Psoriasis in a Patient With Prurigo Nodularis: A Case Report.

Dupilumab is a monoclonal antibody targeting the interleukin-4 (IL-4) and interleukin-13 (IL-13) receptor complex and is used for the treatment of atopic dermatitis (AD), severe asthma, chronic rhinosinusitis with nasal polyps, and prurigo nodularis (PN). Dupilumab has shown high efficacy in PN; however, adverse effects such as conjunctivitis, injection site reactions, and pharyngitis have been reported. Meanwhile, dupilumab-induced psoriasis is a relatively rare adverse effect. Here, we present a case of a 71-year-old woman with a seven-year history of PN that was refractory to topical corticosteroids and narrow-band ultraviolet B (UVB) therapy. The patient received dupilumab injections every two weeks, resulting in an improvement in pruritic nodules. However, three months after the initiation of dupilumab, multiple scaly erythematous plaques appeared on the trunk and extremities. Skin biopsy revealed parakeratosis, regular acanthosis with epidermal thickening, loss of the granular layer, and subcorneal neutrophilic infiltration. Based on these findings, the patient was diagnosed with dupilumab-induced psoriasis. After discontinuing dupilumab and initiating topical corticosteroid therapy, the psoriatic lesions showed significant improvement within three months. Psoriasis induced by dupilumab has been documented in multiple reports involving patients with atopic dermatitis. Only one case of dupilumab-induced psoriasis in a PN patient has been reported, which was limited to the scalp. To the best of our knowledge, this case represents the first report of extensive psoriasiform lesions on the trunk and extremities in a PN patient. While mild cases may be managed without discontinuing dupilumab, severe cases may require cessation of the drug. This case highlights the first report of extensive psoriasiform lesions in a PN patient with dupilumab. Dermatologists should be aware that dupilumab can induce psoriasiform lesions in PN patients and should conduct careful monitoring during treatment. Additionally, discontinuation of dupilumab should be considered in severe cases.