• Definition

    Tonsillitis is inflammation (swelling) of the tonsils.

    See also:

    • Sore throat
    • Strep throat

    Causes, incidence, and risk factors

    The tonsils are lymph nodes in the back of the mouth and top of the throat. They normally help to filter out bacteria and other germs to prevent infection in the body.

    Strep throat is one cause of tonsilitis.

    The tonsils may become so overwhelmed by a bacterial or viral infection that they swell and become inflamed, causing tonsillitis. The infection may also be present in the throat and areas around it, causing inflammation of the pharynx. The pharynx is in the back of the throat, between the tonsils and voicebox (larynx). See: Pharyngitis

    Tonsillitis is very common, especially in children.