Pus or White Patches
White patches [7] are typically signs of infection when you have them at the back of the throat or on the tonsils, especially due to mononucleosis, tonsillitis, or strep throat; they are often related to a syphilitic infection.
Viral and bacterial infections can cause these reactions. Your doctor may need to do a throat swab to diagnose strep throat, a form of bacterial throat infection. If you are not recovering with rest and water, it is essential that you contact a physician.