Paradoxical reaction under dupilumab triggered by occasional ketoprofen intake.

Dupilumab, a monoclonal antibody targeting the IL-4/13 signaling pathway, effectively treats moderate-to-severe atopic dermatitis (AD). Common side effects include injection site reactions, conjunctivitis, and respiratory infections. We report the case of a 28-year-old woman with severe AD involving the periocular and chin regions, genital areas, arms, and legs (Eczema Area and Severity Index [EASI]: 24, itch Visual Analog Scale [VAS]: 8) who showed significant improvement after initiating dupilumab therapy. However, following ketoprofen intake for headache relief, she developed a lupus-like erythematous maculopapular rash on the periocular and malar regions. Immunological tests (antinuclear antibody [ANA] and extractable nuclear antigen [ENA]) and photopatch testing ruled out autoimmune or allergic causes. Dupilumab was stopped, and treatment with oral prednisone and cetirizine led to complete resolution. This case highlights a potential drug interaction between dupilumab and ketoprofen, emphasizing the need for awareness of paradoxical facial erythema reactions in patients undergoing dupilumab therapy.