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Am Fam Physician. 2013;88(5):338-340

Guideline source: Infectious Diseases Society of America

Evidence rating system used? Yes

Literature search described? Yes

Guideline developed by participants without relevant financial ties to industry? No

Published source: Clinical Infectious Diseases, September 2012

The Infectious Diseases Society of America (IDSA) has updated its 2002 guideline on managing group A streptococcal pharyngitis. The illness primarily occurs in children five to 15 years of age. Patients typically present with sudden onset of a sore throat, pain with swallowing, and fever. Examination shows tonsillopharyngeal erythema, often with lymphadenitis. The symptoms of streptococcal pharyngitis often overlap with those of viral pharyngitis, and the two cannot be differentiated using clinical features alone unless overt viral features are present.

Diagnosis

Clinical features of group A streptococcal pharyngitis and viral pharyngitis are listed in Table 1. Diagnosis of group A streptococcal pharyngitis should be confirmed using a rapid antigen detection test and/or culture of a throat swab.

Group A streptococcal infection
Sudden onset of sore throat
Age 5 to 15 years
Fever
Headache
Nausea, vomiting, abdominal pain
Tonsillopharyngeal inflammation
Patchy tonsillopharyngeal exudates
Palatal petechiae
Anterior cervical adenitis (tender nodes)
Presentation in winter or early spring
History of exposure to streptococcal pharyngitis
Scarlatiniform rash
Viral infection
Conjunctivitis
Coryza
Cough
Diarrhea
Hoarseness
Discrete ulcerative stomatitis
Viral exanthem

A positive result on rapid antigen detection testing is diagnostic for group A streptococcal pharyngitis. A backup culture should be performed in children and adolescents with negative test results. A backup culture generally is not necessary in adults because the incidence of the illness and the risk of subsequent rheumatic fever are low in adults; however, it can be considered. Antistreptococcal antibody titers are not recommended in the routine diagnosis of acute pharyngitis.

Diagnostic testing is not recommended if clinical features strongly suggest a viral etiology (e.g., cough, rhinorrhea, hoarseness, oral ulcers). Testing is generally not recommended in children younger than three years unless the child has risk factors, such as an older sibling with the illness, because the illness is uncommon in this age group. Follow-up posttreatment testing is not routinely recommended, but may be considered. Testing of household contacts of patients with group A streptococcal pharyngitis is not routinely recommended.

Treatment

Patients with acute group A streptococcal pharyngitis should be treated with an antibiotic that is likely to eradicate the organism, usually for 10 days. Penicillin or amoxicillin is commonly recommended because of its narrow spectrum of activity, few adverse effects, and modest cost. Alternative antibiotics for those with penicillin allergy include a first-generation cephalosporin, clindamycin, clarithromycin (Biaxin), or azithromycin (Zithromax). Table 2 summarizes antibiotic regimens for patients with and without penicillin allergy.

DrugDose/dosageDurationRecommendation strength, quality of evidence
Patients without penicillin allergy
Penicillin V, oralChildren: 250 mg two or three times daily10 daysStrong, high
Adolescents and adults: 250 mg four times daily or 500 mg twice daily
Amoxicillin, oral50 mg per kg once daily (maximum = 1,000 mg)10 daysStrong, high
Alternative: 25 mg per kg twice daily (maximum= 500 mg)
Penicillin G benzathine, intramuscular< 60 lb (27 kg): 600,000 USingle doseStrong, high
≥ 60 lb: 1,200,000 U
Patients with pencillin allergy
Cephalexin (Keflex), oral*20 mg per kg per dose twice daily (maximum = 500 mg per dose)10 daysStrong, high
Cefadroxil, oral*30 mg per kg once daily (maximum = 1 g)10 daysStrong, high
Clindamycin, oral7 mg per kg per dose three times daily (maximum = 300 mg per dose)10 daysStrong, moderate
Azithromycin (Zithromax), oral12 mg per kg once daily (maximum = 500 mg)5 daysStrong, moderate
Clarithromycin (Biaxin), oral7.5 mg per kg per dose twice daily (maximum = 250 mg per dose)10 daysStrong, moderate

Adjunctive therapy with an analgesic or antipyretic (e.g., acetaminophen, nonsteroidal anti-inflammatory drugs) can be considered to treat moderate to severe symptoms or control a high fever. Aspirin should not be used in children, and adjunctive corticosteroids are not recommended in the treatment of group A streptococcal pharyngitis.

Patients with recurrent pharyngitis and laboratory evidence of group A streptococcus may be chronic carriers who are having repeated viral infections. Antibiotics are not generally recommended in this case, but may be considered in the following situations: (1) during a community outbreak of acute rheumatic fever, acute poststreptococcal glomerulonephritis, or invasive group A streptococcal infection; (2) during an outbreak of group A streptococcal pharyngitis in a closed or partially closed community; (3) when the patient has a family or personal history of acute rheumatic fever; (4) when the patient or family has excessive anxiety about group A streptococcal infections; or (5) when tonsillectomy is being considered only because the patient is a chronic carrier.

Other antibiotic regimens have been shown to be substantially more effective than penicillin or amoxicillin alone in eliminating chronic streptococcal carriage. Table 3 summarizes the treatment options.

DrugDose/dosageDurationRecommendation strength,quality of evidence
Clindamycin, oral20 to 30 mg per kg per day in three doses (maximum = 300 mg per dose)10 daysStrong, high
Penicillin and rifampin, oralPenicillin V: 50 mg per kg per day in four doses for 10 days (maximum = 2,000 mg per day)10 daysStrong, high
Rifampin: 20 mg per kg per day in one dose for last four days of treatment (maximum = 600 mg per day)
Amoxicillin/clavulanate (Augmentin), oral40 mg amoxicillin per kg per day in three doses (maximum = 2,000 mg amoxicillin per day)10 daysStrong, moderate
Penicillin G benzathine (intramuscular) and rifampin (oral)Penicillin G benzathine: < 60 lb (27 kg): 600,000 U; ≥ 60 lb: 1,200,000 UPenicillin G benzathine: single doseStrong, high
Rifampin: 20 mg per kg per day in two doses (maximum = 600 mg per day)Rifampin: four days

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