Rectal Cancer Patient Presents With Hand Edema and Erythema

A 50-year-old male is receiving capecitabine with concurrent radiation therapy for stage III rectal cancer. For the past 7 days, the patient has been taking ciprofloxacin for a urinary tract infection. He has a 1-week history of a tingling sensation in both the palms of his hands and soles of his feet, and a 3-day history of hand edema and erythema.

The diagnosis is: