Tonsillitis

Tonsillitis is usually caused by a virus. Bacteria can also cause tonsillitis. The most common bacterial cause of tonsillitis is group A beta-hemolytic streptococcus (GABHS), which also causes Reference strep throat Opens New Window.

Tonsillitis can also be caused by fungi or parasites, but these causes are rare in people who have healthy Reference immune systems Opens New Window.

Although there is no proof that exposure to cigarette smoke can cause tonsillitis, children who live with a smoker have a higher incidence of tonsillectomy, which is a surgical procedure to remove the tonsils.^{Reference 1}

How tonsillitis is spread

Tonsillitis is spread by close contact with an infected person. Droplets of disease-causing agents (Reference pathogens Opens New Window) pass through the air when an infected person breathes, coughs, or sneezes. You may then become infected after breathing in these droplets. Infection can also occur if pathogens get on the skin or on objects that come in contact with your mouth, nose, eyes, or other mucous membranes. Symptoms usually appear about 2 to 5 days after exposure.

A person with tonsillitis caused by strep bacteria is contagious early on and without treatment can remain so for up to 2 weeks. Antibiotics shorten the contagious period, and an infected person is no longer contagious about 24 to 48 hours after beginning antibiotic therapy.

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