A 36-year-old Caucasian female with a long history of atopic dermatitis presented with multiple flares eventually leading to dupilumab therapy. Five months into the dupilumab therapy, she presented with well-demarcated erythematous plaques with silvery scale resembling psoriasis on her knees and shins (body surface area 2%, Psoriasis Area Severity Index 1.6, Investigator' Global Assessment 2). Biopsies were taken to confirm the diagnosis of classic psoriasis. Dupilumab was continued for another month while using clobetasol 0.05% ointment. The patient reported poor adherence to clobetasol therapy, and the lesions persisted. When dupilumab was discontinued, her psoriasis resolved over 6 weeks, but her atopic dermatitis returned. Dupilumab was restarted for atopic dermatitis management, and her psoriasis returned. There appears to be a rare causal association between dupilumab and psoriasis in this case. The mechanism of the drug reaction is yet to be discovered.