The main swollen tonsil cause is when there are more germs or bacteria present in the throat than the tonsils are able to filter out. This swelling and inflammation is commonly referred to as tonsillitis. The tonsils are lymph nodes that are located in the top of the throat and back of the mouth. One of the main functions of the tonsils are to help prevent infections in the body, including bacteria and viruses. There are several types of infections that can cause swollen tonsils.
- Strep Throat. Caused by Group A Streptococcus bacteria, strep throat is the most common bacterial infection of the throat causing swollen tonsils, especially in children between the ages of five and fifteen. Strep spreads from one family member to another by secretions from the nose or mouth. It often occurs in the latter part of fall, winter, or early in the spring. Strep has many different strains and some of them can lead to a scarlet fever rash which is caused by an allergy to a toxin from the strep germ. Occasionally strep can cause rheumatic fever or kidney complications without treatment. It cannot be diagnosed by looking at the throat and needs a lab test for proper diagnosis.
- Pharyngitis. When the tonsils become inflamed and swollen, the pharynx may also get infected causing pharyngitis. The pharynx is also in the back of the throat and is located between the tonsils and the larynx. Pharyngitis most often occurs in the winter months.
- Colds or Flu. Viral infections like colds and flu can cause a sore throat and inflammation of the tonsils. The sore throat is often caused by the drainage from the nose or sinuses that run down the back of the throat. Viral infections do not respond to antibiotics. If the sinus cavities become infected the person may need antibiotics to take care of the infection.
- Mononucleosis. Another infection that can cause sore throats and swollen tonsils is mononucleosis. Aptly named the “kissing disease” it most often occurs in teens from fifteen to seventeen. The infection is caused by the Epstein-Barr virus which is spread from one individual to another by saliva. It causes a fever, sore throat and swollen lymph glands, including the tonsils.
- Allergic Rhinitis. People with bad allergies may also get a sore throat. Sore throats from allergies can also inflame the tonsils or other parts of the throat causing them to swell.