Acute Pharyngitis, Tonsillitis, and Peritonsillar Abscess

Most cases of pharyngitis are viral, but distinguishing viral from bacterial infections clinically is difficult. A rapid antigen detection test and/or throat culture is required to distinguish viral pharyngitis from pharyngitis due to group A Streptococcus (GAS), although a clinical scoring system can be helpful in predicting viral cases. Fusobacterium necrophorum, an anaerobe, is not identified on routine throat culture, yet it is a common cause of pharyngitis and peritonsillar abscess in adolescents and young adults. Peritonsillar abscess usually requires surgical drainage by needle aspiration or incision, in addition to antibiotic therapy. This chapter reviews the epidemiology, microbiology, clinical features, differential diagnosis, and treatment of pharyngitis and peritonsillar abscess.