A 14-year-old girl presented to the Emergency Department with right gluteal pain, functional limitation of the left hip, sciatica, and low-grade fever. Tests revealed elevated inflammatory markers, and ultrasound showed joint effusion and muscle thickening. After infectious and rheumatologic evaluations, reactive arthritis with enthesitis caused by Salmonella was diagnosed, confirmed by a detailed medical history. Antibiotic therapy was discontinued, and sulfasalazine treatment was started, leading to clinical improvement. Reactive arthritis usually occurs after gastrointestinal infections and typically resolves within 3-5 months with supportive therapy.