INTRODUCTION – AGENTS
Pharyngitis and tonsillitis both are most frequently caused by Streptococcus pyogenes (group A beta-hemolytic streptococcus). However, many other organisms have been cultured in pharyngitis and tonsillitis, including viridans group Streptococci, Staphylococcus aureus, and Haemophilus influenzae. Oral flora such as Actinomyces can also be a bacterial etiology. It is not uncommon for the infection to be caused by a mix of aerobic and anaerobic flora.
Viruses with a predilection for the upper respiratory tract can also be causative and are, in fact, more prevalent. These include rhinoviruses, influenza viruses, adenovirus, enteroviruses, reovirus, respiratory syncytial virus, parainfluenza viruses, and coronaviruses. Infection with the Epstein-Barr virus (EBV) is common and may be accompanied by extensive tonsillar exudates. Other etiologies include toxoplasmosis, candida, tularemia, and cytomegalovirus.
Pharyngitis and tonsillitis are most commonly seen in children and teenagers (though rarely in children under 2), and are not unusual in adults. In general, it is more likely for children than for adults to have a bacterial etiology of a sore throat. There is a peak incidence in Streptococcus pharyngitis from November to May.
Pharyngitis and tonsillitis both present with dysphagia, odynophagia, and a low-grade fever (Table 9.1). There may be erythema of the pharynx. In a tonsillar infection in which the many crevices (or crypts) harbor bacterial infection, patients may complain of bad breath and foul-tasting whitish lumps on the tonsils.