Tonsillitis is irritation and swelling of the tonsils, which are in the back of the throat. Tonsillitis may be caused by a viral or bacterial infection, such as strep throat. Symptoms of tonsillitis include a sore throat, red or swollen tonsils, difficulty swallowing, fever, headache, among other aches and pains. Sometimes, tonsillitis causes loss of voice.


Tonsillitis most commonly affects children between preschool ages and the mid-teenage years. Common symptoms of tonsillitis include:

  • Red, swollen tonsils
  • White or yellow coating or patches on the tonsils
  • Sore throat
  • Difficult or painful swallowing
  • Fever
  • Enlarged, tender glands (lymph nodes) in the neck
  • A scratchy, muffled or throaty voice
  • Bad breath
  • Stomachache, particularly in younger children
  • Stiff neck
  • Headache


Tonsillitis is most often caused by common viruses, but bacterial infections can also be the cause.

The most common bacterium causing tonsillitis is Streptococcus pyogenes (group A streptococcus), the bacterium that causes strep throat. Other strains of strep and other bacteria also may cause tonsillitis.

Risk Factors

Risk factors for tonsillitis include:

  • Young age.
  • Frequent exposure to germs.


Inflammation or swelling of the tonsils from frequent or ongoing (chronic) tonsillitis can cause complications such as:

  • Difficulty breathing
  • Disrupted breathing during sleep (obstructive sleep apnea)
  • Infection that spreads deep into surrounding tissue (tonsillar cellulitis)
  • Infection that results in a collection of pus behind a tonsil (tonsillar abscess)


The germs that cause viral and bacterial tonsillitis are contagious. Therefore, the best prevention is to practice good hygiene. Teach the children to:

  • Wash their hands thoroughly and frequently, especially after using the toilet and before eating
  • Avoid sharing food, drinking glasses or utensils used by other people.