A nurse is caring for a 32-year-old female client who presents with fatigue and joint pain. The client reports experiencing a rash on her cheeks that worsens with sun exposure. Nurse's notes indicate a butterfly rash is visible across the client's cheeks and the client reports difficulty concentrating with a history of intermittent fevers. Joint swelling is noted in the left knee and the client rates pain as 6/10. Based on these findings, which condition is the client most likely experiencing?