Tonsillitis
Inflammation of the palatine tonsils, usually viral but sometimes bacterial (chiefly group A Streptococcus), where clinical scoring rather than routine testing decides who actually benefits from an antibiotic.
First principles
The tonsils are lymphoid tissue positioned to sample everything swallowed and inhaled
The palatine tonsils sit at the junction of the oral cavity and oropharynx as part of Waldeyer's ring, deliberately exposed to inhaled and swallowed pathogens so the immune system can sample and respond to them. That exposure means they are frequently infected, most often by respiratory viruses (rhinovirus, adenovirus, and characteristically Epstein-Barr virus) and less often by bacteria, principally group A Streptococcus (Streptococcus pyogenes). The crypts and follicles of the tonsil become inflamed and swollen, producing the sore throat, erythema and, when purulent, the visible white-yellow exudate.
Educational content pending clinical review. Not medical advice.