Inflammation of the pharynx.
Pharyngitis is an inflammatory illness of the mucous membranes and underlying structures of the throat. Inflammation usually involves the nasopharynx, uvula, and soft palate. The illness can be caused by bacteria, viruses, mycoplasmas, fungi, and parasites, and by recognized diseases of uncertain causes. More than 90 percent of all tonsillitis is caused by Streptococcus pyogenes, adenoviruses, influenza viruses, parainfluenza viruses, Epstein-Barr virus, enteroviruses, and Mycoplasma pneumoniae.