If the sore throat is due to a viral infection, the symptoms are usually milder compared to bacterial infection. During diagnosis, the doctor will ask you about the symptoms will look in to your mouth and throat using a lighted instrument. If there are tonsils, it may be red and have white spots on them.
Your doctor may also take a throat culture by gently swabbing the back of your throat. The culture will be sent to a laboratory to identify the cause of your throat infection.