Bacteria in the Streptococcus anginosus group appear to predict renewal of PTA symptoms, while Streptococcus pyogenes was not found in our patients with symptom renewal. Certain subgroups of patients should be followed more closely.

Peritonsillar abscess (PTA) is traditionally considered only a purulent complication of acute tonsillitis (AT), but may be related to infection of minor salivary glands. We analysed the presence of peritonsillar minor salivary glands and inflammation patterns in 114 adult tonsils representing three patient groups: recurrent AT, chronic tonsillitis (CT), and PTA. Samples acquired from elective tonsillectomies were stored in formalin, and after preparation were microscopically examined for inflammation and fibrotic changes. Clinical features and histological characteristics were compared between the groups. Of all tonsils, the minor salivary glands were present in 77 (67.5%). Glands located near the tonsillar tissue showed signs of infection in 73 (94.8%), while only 3 (15.0%) of 20 glands located deeper in the peritonsillar space were infected. Compared to patients with recurrent AT and CT, those with PTA more often presented with periductal inflammation, p < 0.011 (PTA 82.1%, AT 42.9%, and CT 63.6%). The majority of our 114 tonsillectomy specimens, collected from patients with AT, CT, or PTA, presented with infected minor salivary glands, and inflammation of the peritonsillar space glands was evident. To further elucidate the association between these glands and PTA, tonsillar samples should be collected and analysed from patients during the acute phase of infection.