What Are the Causes of an Infection of the Tonsils?

Tonsils are two clumps of lymph tissue situated on either side of the throat. They kill germs, build your immunity and help your body in resist infections. An infection of the tonsils is called tonsillitis 12. Tonsillitis usually occurs due to viral or bacterial causes 12. According to the Mayo Clinic, when these germs enter your body, they are engulfed, and this results in a low-grade infection in your tonsils.

Spread of Tonsillitis

An infection can spread from one person to another by contact, kissing a person with the bacteria or contact with someone's infected mucus through a sneeze or a cough.

Viral Causes

The viruses that cause colds or flu are common causes of tonsillitis 12. Such infections are usually mild. The Epstein Barr virus can cause infectious mononucleosis, which may lead to severe tonsillitis 12. This is also called "kissing disease," as this virus is transmitted through saliva. Symptoms are throat pain, difficulty swallowing, stomachache, fever and fatigue. Infection with Coxsackie virus results in a very painful tonsil infection with blisters on hands, feet, mouth and throat.

Bacterial Causes

Bacteria, usually streptococcus group A, are responsible for up to 30 percent of tonsillitis cases, according to the American Academy of Otolaryngology and Head and Neck Surgery 12. Strep throat produces painful swallowing, fever, white spots on the tonsils and painful glands in the neck. Your doctor will do a throat swab to diagnose strep throat and prescribe an antibiotic.

A bacterium called N. gonorrhea is a rare cause of tonsillitis 12. Also--very rarely, due to vaccination--the bacteria that cause diphtheria cause tonsil infection. Symptoms are a sore throat, a membrane over the tonsils, a mild fever and swollen neck glands.

Other Causes

Allergies can cause tonsillitis, as can smoking or long-term exposure to cigarette smoke 12.