<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been experiencing knee swelling, elbow swelling, abnormal appearing skin and feeling ill. Can you please tell me whats wrong with me?  <response>: Based on your symptoms, it seems like you are suffering from septic arthritis. It is an infection in the joint and can be quite serious if not treated promptly. I suggest we start the treatment as soon as possible. 