- Group A Ã-hemolytic streptococcus (GAS) is the most common bacterial cause of acute pharyngitis, responsible for 5%-15% of sore throat visits in adults and 20%-30% in children.
- Although acute pharyngitis is one of the most frequent illnesses for which pediatricians and other primary care physicians are consulted, with an estimated 15 million visits per year in the U.S., only a relatively small percentage of patients with acute pharyngitis (20%-30% in children, fewer in adults) are infected by GAS pharyngitis.
- Moreover, the signs and symptoms of GAS and nonstreptococcal pharyngitis overlap so broadly that accurate diagnosis on clinical grounds alone is usually impossible.
- Accurate diagnosis of streptococcal pharyngitis followed by appropriate antimicrobial therapy is important:
- To prevent acute rheumatic fever with and without carditis
- To prevent suppurative complications (e.g., peritonsillar abscess, cervical lymphadenitis, mastoiditis and possibly other invasive infections)
- To improve clinical symptoms and signs
- For rapid decrease in contagiousness
- To reduce transmission of GAS to family members, classmates, and other close contacts of the patient
- To allow for the rapid resumption of usual activities
- To minimize potential adverse effects of inappropriate antimicrobial therapy.
- Penicillin or amoxicillin remains the treatment of choice, and azithromycin, clarithromycin, clindamycin or a 1st generation cephalosporina for the penicillin-allergic patient.
- With the exception of very rare infections by certain other bacterial pharyngeal pathogens (e.g., Corynebacterium diphtheriae and Neisseria gonorrhoeae) (Table 2), antimicrobial therapy is of no proven benefit as treatment for acute pharyngitis due to organisms other than Group A streptococci.
- Swabbing the throat and testing for GAS pharyngitis by rapid antigen detection test (RADT) and/or culture should be performed because the clinical features alone do not reliably discriminate between GAS and viral pharyngitis except when overt viral features like rhinorrhea, cough, oral ulcers and/or hoarseness are present.
- In children and adolescents, negative RADT tests should be backed up by a throat culture (SR-H). Positive RADTs do not necessitate a back-up culture because they are highly specific (SR-H).
- Routine use of back up throat cultures for those with a negative RADT is not necessary for adults in usual circumstances because there is a low incidence of GAS pharyngitis in adults and the risk of subsequent acute rheumatic fever is generally exceptionally low in adults with acute pharyngitis (SR-M).
- Anti-streptococcal antibody titers are not recommended in the routine diagnosis of acute pharyngitis since they reflect past but not current events (SR-H).
- Testing for GAS pharyngitis usually is not recommended for children or adults with acute pharyngitis with clinical and epidemiologic features that strongly suggest a viral etiology (e.g., cough, rhinorrhea, hoarseness, and oral ulcers) (SR-H).
- Diagnostic studies for GAS pharyngitis are not indicated for children < 3 years old because acute rheumatic fever is rare in these children and the incidence of streptococcal pharyngitis and the classic presentation of streptococcal pharyngitis are uncommon in this age group.
- Follow-up post-treatment throat culture or RADT is not recommended routinely but may be considered in special circumstances (SR-H).
- Diagnostic testing or empiric treatment of asymptomatic household contacts of patients with acute streptococcal pharyngitis is not routinely recommended (SR-M).
Table 1. Epidemiologic and Clinical Features of Group A Streptococcal Pharyngitis
Features suggestive of GAS pharyngitis:
- Sudden onset of sore throat
- Age 5-15 years
- Nausea, vomiting, abdominal pain
- Tonsillopharyngeal inflammation
- Patchy tonsillopharyngeal exudates
- Palatal petechiae
- Anterior cervical adenitis (tender nodes)
- Winter-early spring presentation
- History of exposure to strep pharyngitis
- Scarlatiniform rash
Features suggestive of viral pharyngitis:
- Discrete ulcerative stomatitis
- Viral exanthema
Table 2. Microbial Etiology of Acute Pharyngitis
|Group A streptococcus||Pharyngotonsillitis, scarlet fever|
|Group C G streptococcus||Pharyngotonsillitis|
|Arcanobacterium haemolyticum||Scarletiniform rash, Pharyngitis|
|Mixed anaerobes||Vincentsâ angina|
|Fusobacterium necrophorum||Lemierreâs syndrome, peritonsillar abscess|
|Francisella tularensis||Tularemia (oropharyngeal)|
|Yersinia enterocolitica||Enterocolitis, pharyngitis|
|Herpes simplex virus 1 and 2||Gingivostomatitis|
|Influenza A and B||Influenza|
|HIV||Primary Acute HIV Infection|
|Mycoplasma pneumoniae||Pneumonitis, bronchitis|
|Chlamydophila pneumoniae||Bronchitis, pneumonia|