A 29-year-old nurse presents with 5 weeks of progressively worsening hand discomfort. She reports intense pruritus and a burning sensation, especially after work. She recently started working in an ICU and has been washing her hands and using alcohol-based sanitizer far more frequently than before. She denies new jewelry, gloves with powdered latex, or new lotions at home. Physical examination shows dry, fissured skin with erythema and scaling over the fingers, finger webs, and dorsum of both hands. No vesicles are seen. Which of the following is the most likely diagnosis?