Tonsillitis | Causes & Risk Factors


What causes tonsillitis?

Most cases of tonsillitis are caused by viruses. For example, the virus that causes mononucleosis (called the Epstein-Barr virus) can cause tonsillitis. Tonsillitis is only caused by bacteria in about 15% to 30% of cases. Bacterial tonsillitis is most often caused by a certain type of streptococcus (or “strep”) bacteria. In these cases, the illness may be called “ strep throat.”

Written by editorial staff

Reviewed/Updated: 05/14
Created: 08/09