Chronic actinic dermatitis (CAD) is a rather rare photosensitive disease characterized by a persistent eczematous eruption in sun-exposed sites. The pathogenesis of CAD has not been completely elucidated. The clinical treatment of CAD is still challenging and not standardized. Some patients with severe CAD have achieved satisfactory clinical results with dupilumab when conventional therapies have failed. We herein report the case of a 45-year-old male with severe CAD who responded rapidly to combined treatment with dupilumab (600 mg for 1 week, and then 300 mg every 2 weeks) in 2 months. The patient experienced continuous improvement and no side effects from dupilumab (300 mg every month), having ceased other systemic medications. Dupilumab could be considered as an alternative or adjunctive treatment for CAD.