Acute pharyngitis may be caused by a wide variety of microbial agents (Table 1). The relative importance of each of these agents varies greatly depending on a number of epidemiologic factors, including age of the patient, season of the year, and geographic locale.
Viruses
Most cases of acute pharyngitis are viral in etiology and involve the pharynx as well as other portions of the respiratory tract as manifestations of the common cold, influenza, or croup. Examples include the rhinoviruses, coronaviruses, influenza A and B, and the parainfluenza viruses. Certain viral infections causing sore throat may exhibit clinical manifestations that are rather distinctive. Examples include enteroviruses (herpangina due to Coxsackie A), Epstein-Barr virus (infectious mononucleosis), cytomegalovirus (cytomegalovirus mononucleosis), adenovirus (pharyngoconjunctival fever, acute respiratory disease of military recruits), and herpes simplex virus (pharyngitis, gingivitis, and stomatitis). In many instances, however, the illnesses caused by these agents may overlap so broadly with that of streptococcal pharyngitis as to be clinically indistinguishable. Thus, Epstein-Barr virus, adenovirus, and herpes virus may all cause fever, exudative pharyngitis, and cervical adenitis.
Several studies have documented the role of primary herpesvirus type 1 infection as a cause of acute pharyngitis in college students.1-4 Herpesvirus type 2 can occasionally cause a similar illness as a consequence of oral-genital sexual contact.5 Although herpesvirus infections may involve the anterior oral cavity (vesicular or ulcerative gingivostomatitis) as well as the posterior pharynx, they do not routinely do so. Only about one-fourth of students with culturally and serologically proven primary herpes simplex type 1 pharyngitis studied by Glezen et al,2 for example, had gingivostomatitis.
The role of viruses in the cancerogenesis