Development of IL‐17A inhibitor‐induced atopic dermatitis‐like rash in psoriasis patients: Insights into immune shift

Abstract Cases of atopic dermatitis (AD)‐like rash induced by IL‐17A inhibitor secukinumab treatment (SI‐AD) have been recently reported in psoriasis patients. To identify immune and inflammatory factors expression in SI‐AD. A panel of 15 immune and inflammatory factors in peripheral blood samples from various groups, including patients with patients with SI‐AD, psoriasis with secukinumab (S‐stable), advanced psoriasis patients (Advanced) and healthy controls (HC). Interleukin‐10 (IL‐10), IL‐4 and IL‐17A were detected in skin tissue biopsy samples by immunohistochemistry and real‐time quantitative polymerase chain reaction. The immunoglobulin E levels in the SI‐AD patients exceeded normal values. The IL‐10 levels in SI‐AD patients were higher than those in S‐stable patients, advanced patients and HC. The IL‐4 levels in SI‐AD patients were higher than that in S‐stable patients and HC. The IL‐17A levels in SI‐AD patients were higher than those in advanced psoriasis patients and HC, but no significant differences were observed between SI‐AD patients and S‐stable patients. IL‐10 and IL‐4 levels were higher in AD‐like rashes than in healthy skin, while IL‐17A did not differ significantly between the two. Upon discontinuing secukinumab, and switching to oral cyclosporine, antihistamines, Janus kinase 1 inhibitor and topical glucocorticoids, SI‐AD patients experienced significant improvement in their skin lesions. Upon reexamination, all 15 immune and inflammatory factors returned to normal levels. Immune shift from Th17 towards Th2 may occur in SI‐AD, as indicated by abnormal expression of multiple immune and inflammatory factors observed in peripheral blood and skin tissues.