Viruses are the most common cause of pharyngitis. GABHS pharyngitis is responsible for merely 5%–15% of cases in adults, with other bacteria responsible to a lesser extent. Unfortunately, 60% of adults with pharyngitis receive antibiotics.1
Fever, cervical lymphadenopathy, tonsillar exudates, and throat pain are the most common clinical manifestations. Distinguishing bacterial from viral pharyngitis on clinical grounds alone is difficult.
- Acute HIV infection should be considered in the setting of pharyngitis with atypical lymphocytosis and negative Streptococcus and Epstein–Barr virus testing.
- Epiglottitis should be considered in the febrile patient with severe throat pain, odynophagia, new-onset drooling, and dysphagia.
- Suppurative complications including peritonsillar or retropharyngeal abscess should be considered in the patient with severe unilateral pain, muffled voice, trismus, and dysphagia.
- Diagnostic testing is usually reserved for symptomatic patients with exposure to a case of streptococcal pharyngitis, those with signs of significant infection (fever, tonsillar exudates, and cervical adenopathy) or whose symptoms persist despite symptomatic therapy, and patients with a history of rheumatic fever.
- Rapid antigen detection testing (RADT) is useful for diagnosing GABHS (>90% sensitivity and specificity), which requires antimicrobial therapy to prevent suppurative complications and rheumatic fever. A negative test does not reliably exclude GAS, making throat culture necessary if clinical suspicion is high.
- Serology for Epstein–Barr virus (e.g., heterophile agglutinin or monospot) and examination of a peripheral blood smear for atypical lymphocytes should be performed when infectious mononucleosis is suspected.
- Most cases of pharyngitis are self-limited and do not require antimicrobial therapy.
Treatment for GABHS is indicated with a positive culture or RADT, if the patient is at high risk for development of rheumatic fever, or if the diagnosis is strongly suspected, pending culture results. Treatment options include penicillin V 500 mg PO q12h for 10 days, clindamycin 300 mg PO q8h for 10 days, azithromycin 500 mg PO on day 1 followed by 250 mg qday on days 2–5, or benzathine penicillin G 1.2 million units IM as a one-time dose.2 In some communities up to 15% of the GABHS isolates are resistant to macrolides.
- Gonococcal pharyngitis is treated with ceftriaxone 250 mg IM as a single dose, plus azithromycin or doxycycline.
- Barnett ML, Linder JA. Antibiotic prescribing to adults with sore throat in the United States, 1997-2010. JAMA Intern Med. 2014;174(1):138-140. [PMID:24091806]
- Shulman ST, Bisno AL, Clegg HW, et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis. 2012;55(10):1279-1282. [PMID:23091044]
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