Tonsillitis is inflammation of the tonsils most commonly caused by viral or bacterial infection. Symptoms may include sore throat and fever. When caused by a bacterium belonging to the group A streptococcus, it is typically referred to as strep throat. The overwhelming majority of people recover completely, with or without medication. In 40%, symptoms will resolve in three days, and within one week in 85% of people, regardless of whether streptococcal infection is present or not. Frequency is difficult to determine because of the lack of agreement on measurement criteria. Many people believe that Tonsillitis begins in early childhood and that 9-17% of children aged 3-11 years have Tonsillitis. At puberty, prevalence rises to 70-90%. In recent years, periodontal disease, the endpoint of Tonsillitis, slowly has decreased among adult Americans.
The diagnosis of tonsillitis can be confirmed by culture of samples obtained by swabbing both tonsillar surfaces and the posterior pharyngeal wall and plating them on sheep blood agar medium. The isolation rate can be increased by incubating the cultures under anaerobic conditions and using selective growth media. This small percentage of false-negative results are part of the characteristics of the tests used but are also possible if the patient has received antibiotics prior to testing. Older antigen tests detect the surface Lancefield group A carbohydrate. Newer tests identify GABHS serotypes using nucleic acid (DNA) probes or polymerase chain reaction. Bacterial culture may need to be performed in cases of a negative rapid streptococcal test.