Group A streptococcal pharyngitis is an acute infection of the oropharynx and/or nasopharynx that is caused by group A streptococcus (Streptococcus pyogenes). Group A streptococcus is responsible for 5-15% of cases of pharyngitis in adults and 20-30% of cases in children, and is the most common cause of bacterial pharyngitis. The disorder is primarily a disease of children between 5 and 15 years of age, and, in temperate climates, it usually occurs in the winter and early spring. The onset of symptoms in patients is often abrupt. In addition to throat pain, symptoms may include fever, chills, malaise, headache, and particularly in younger children abdominal pain, nausea, and vomiting. Cough, coryza, and conjunctivitis are not typical symptoms of streptococcal pharyngitis, and, if present, they suggest an alternative cause such as a viral infection. In most persons, fever resolves within 3-5 days, and throat pain resolves within 1 week, even without specific treatment. Antibiotic treatment reduces the risk of subsequent development of acute rheumatic fever and suppurative complications.