Diaper rash is a common condition that affects almost all babies at some point. While most cases of diaper rash can be treated effectively at home, there are certain instances where it is important to seek medical attention. If your baby's rash is severe, persists for more than a few days, is accompanied by other symptoms such as fever or diarrhea, or appears to be spreading, it is recommended to call a doctor. Additionally, if your baby appears to be in pain or uncomfortable, or if you notice any signs of infection such as pus or blisters, it is important to seek medical advice. By being aware of when to call a doctor for diaper rash, you can help ensure that your baby receives the appropriate care and treatment they need.