Abstract
Pharyngitis is an inflammatory condition of the pharynx and/or tonsils commonly seen in both children and adults. Viruses and bacteria represent the most common encountered etiologic agents-yeast/fungi and parasites are infrequently implicated. Some of these are predominantly observed in unique populations (eg, immunocompromised or unvaccinated individuals). This article (part 1 of 3) summarizes the impact of acute pharyngitis on the health care system and reviews the etiologic agents of acute pharyngitis, including both emerging and reemerging pathogens that health care providers should consider when evaluating their patients. Finally, it sets the stage for parts 2 and 3, which discuss the current and evolving state of diagnostic testing for acute pharyngitis.