AUTHOR=Qiu Fang , Chen Weiquan , Zhou Ying TITLE=Adalimumab induced psoriasis in Crohn’s disease and treatment with ustekinumab: case report and special histopathological findings JOURNAL=Frontiers in Medicine VOLUME=Volume 11 - 2024 YEAR=2025 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2024.1507524 DOI=10.3389/fmed.2024.1507524 ISSN=2296-858X ABSTRACT=This case report presents an instance of Tumor Necrosis Factor-α Inhibitor-induced psoriasis (TNFiIP), also known as paradoxical psoriasis, in a 30-year-old male with fistulizing Crohn’s disease. The patient developed extensive erythematous and scaly lesions on the palms, lower limbs, ankles, and soles after 4 months of adalimumab monotherapy. Histopathological analysis revealed a pattern of psoriasiform dermatitis with notable dermal neutrophil and eosinophil infiltration, distinguishing TNFiIP from idiopathic psoriasis. The patient’s condition significantly improved following the transition from adalimumab to ustekinumab, which highlights the importance of alternative therapeutic strategies for patients who exhibit paradoxical reactions to TNF-α inhibitors.