What is the appropriate evaluation and management for a patient presenting with pharyngitis?

Evaluation and Management of Pharyngitis

For patients presenting with pharyngitis, do not prescribe antibiotics based on clinical appearance alone—use a clinical scoring system to identify candidates for testing, perform microbiological confirmation with rapid antigen detection test (RADT) or throat culture, and reserve antibiotics exclusively for confirmed Group A Streptococcal (GAS) infection, treating with penicillin or amoxicillin for 10 days. 1

Initial Clinical Assessment

Identify Obvious Viral Features (No Testing Needed)

Do not test or treat patients who present with any of the following viral indicators, as these strongly suggest viral etiology and testing will likely identify harmless carriers rather than true infection 1:

• Cough 1
• Rhinorrhea 1
• Hoarseness 1
• Conjunctivitis 2
• Discrete oral ulcers or ulcerative stomatitis 1

The majority of acute pharyngitis cases (70-95%) are viral and self-limited, requiring only supportive care. 3, 4, 5 Viruses implicated include adenovirus, influenza, parainfluenza, rhinovirus, respiratory syncytial virus, coxsackievirus, echoviruses, herpes simplex virus, and Epstein-Barr virus. 2

Age-Specific Exclusions

• Children <3 years old: Do not routinely test, as GAS pharyngitis and acute rheumatic fever are rare in this age group. 1 Exception: Consider testing if an older sibling has confirmed GAS infection. 1

Risk Stratification Using Clinical Scoring

For patients without obvious viral features, use a clinical scoring system to determine who requires testing. 6 The Centor criteria (modified for children) include 4, 5:

1. History of fever
2. Tonsillar exudates
3. Tender anterior cervical lymphadenopathy
4. Absence of cough

Testing strategy based on score 4, 5:

• 0-1 criteria: Do not test or treat—GAS infection is highly unlikely 4, 5
• 2 criteria: Perform RADT; treat only if positive 4, 5
• 3-4 criteria: Perform RADT; treat only if positive (or consider empiric treatment in adults with 4 criteria in some guidelines, though microbiological confirmation is preferred) 4, 5

Important caveat: Even with all clinical features present, only 35-50% of cases are confirmed GAS-positive, underscoring the necessity of laboratory confirmation. 7 Clinical scoring systems have comparable or slightly higher diagnostic accuracy than clinician judgment alone, but their principal utility is identifying low-probability patients to avoid unnecessary testing. 6

Diagnostic Testing

Children and Adolescents (Ages 3-18)

Two-step approach required 1, 2:

1. Perform RADT first (specificity ≥95%, sensitivity 80-90%) 1, 2
2. If RADT is negative, confirm with throat culture because RADT misses 10-20% of true infections 1, 2
3. If culture returns positive, initiate antibiotics—treatment within 9 days of symptom onset still prevents acute rheumatic fever 2

This two-step algorithm is mandatory in pediatric patients due to higher GAS prevalence (20-30% in ages 5-15) and greater risk of acute rheumatic fever compared to adults. 2, 8

Adults

RADT alone is sufficient 1, 2:

• A negative RADT does not require backup throat culture 1, 2
• This approach is justified by low GAS prevalence in adults (5-15%) and extremely low risk of acute rheumatic fever 2, 8, 5
• Specificity ≥95% makes false positives rare 2

Proper Testing Technique

Ensure samples are collected from both the posterior pharyngeal wall and tonsils to maximize diagnostic yield. 2 Improper swabbing technique is a common cause of false-negative results. 2

Treatment of Confirmed GAS Pharyngitis

First-Line Therapy (Non-Allergic Patients)

Penicillin or amoxicillin for 10 days is the definitive treatment of choice based on proven efficacy, narrow spectrum, safety, low cost, and zero documented resistance. 1, 3

Specific dosing 2:

• Penicillin V: 250 mg 2-3 times daily (<27 kg); 500 mg 2-3 times daily (≥27 kg and adults) for 10 days
• Amoxicillin: 50 mg/kg once daily (maximum 1 g) for 10 days
• Benzathine penicillin G (IM): Single dose of 600,000 U (<27 kg); 1,200,000 U (≥27 kg)—useful when adherence is a concern

The full 10-day course is essential to eradicate the organism and prevent acute rheumatic fever; shortening the course by even a few days results in appreciably higher treatment failure rates. 9

Penicillin-Allergic Patients

Non-anaphylactic allergy 1, 7:

• First-generation cephalosporin (cefadroxil or cephalexin) for 10 days 1, 7

Anaphylactic or immediate-type hypersensitivity 1, 2:

• Clindamycin: 20 mg/kg/day divided 3 times daily (maximum 1.8 g/day) for 10 days—only ~1% GAS resistance in the U.S. 2, 7
• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 2
• Clarithromycin: 15 mg/kg/day divided 2 times daily for 10 days 2

Caution with macrolides: 5-8% macrolide resistance rates exist in most U.S. areas. 7

Avoid broad-spectrum cephalosporins (cefdinir, cefixime, cefpodoxime) when narrow-spectrum options are available, as they promote antibiotic resistance and increase cost. 7 Never use fluoroquinolones, tetracyclines, or sulfonamides for GAS pharyngitis. 7

Symptomatic Management

For All Patients (Regardless of GAS Status)

Analgesics/antipyretics 1, 2:

• Acetaminophen or NSAIDs (ibuprofen) for moderate to severe symptoms or high fever 1
• Avoid aspirin in children due to Reye syndrome risk 1

Adjunctive measures 2, 7:

• Adequate hydration
• Warm saline gargles
• Throat lozenges
• Topical anesthetics
• Rest

Corticosteroids are not recommended as adjunctive therapy. 1

Expected Clinical Response

Patients with confirmed GAS pharyngitis should experience clinical improvement within 24-48 hours of starting penicillin therapy, with fever declining and symptoms lessening. 9 If symptoms do not improve within 48-72 hours, reevaluate for concomitant viral infection, alternative diagnosis, or (rarely) treatment failure. 9 Patients are generally non-contagious after 24 hours of antibiotic therapy. 9

Common Pitfalls to Avoid

Testing and Treatment Errors

• Do not treat based on clinical appearance alone without laboratory confirmation—even experienced physicians cannot reliably differentiate bacterial from viral pharyngitis, and exudates/white patches occur with viral infections. 2, 7, 3
• Do not test or treat asymptomatic household contacts—up to one-third may be asymptomatic carriers, and prophylactic antibiotics do not reduce subsequent infection rates. 1, 2
• Do not perform routine post-treatment cultures in asymptomatic patients—positive tests likely reflect carrier status rather than treatment failure. 1, 2

Antibiotic Stewardship

• Withhold antibiotics entirely when GAS testing is negative—the vast majority of these cases are viral and self-limited. 2
• Do not switch antibiotics without microbiological indication—this increases adverse effects without clinical benefit. 2
• Do not discontinue antibiotics prematurely when symptoms improve—this leads to treatment failure and potential complications. 9

Allergy Labeling

• Do not label patients as penicillin-allergic based solely on a benign maculopapular rash that occurred during viral illness—this represents a non-IgE-mediated reaction, not true allergy. 7 More than 90% of individuals with reported penicillin allergy are not truly allergic. 7
• Amoxicillin-associated rash in the setting of viral pharyngitis (especially EBV, where 30-100% develop rash) does not indicate true penicillin allergy and should not preclude future use. 7

Recurrent Pharyngitis

Consider that patients with recurrent episodes may be chronic GAS carriers experiencing repeated viral infections rather than true recurrent streptococcal infections. 1 GAS carriers do not require antimicrobial therapy, are unlikely to spread infection, and are at little to no risk for complications. 1

Tonsillectomy is not recommended solely to reduce the frequency of GAS pharyngitis. 1

Special Circumstances

Follow-Up Testing

Routine post-treatment throat cultures or RADT are not recommended but may be considered in special circumstances 1:

• History of acute rheumatic fever
• Outbreaks in closed settings (schools, military barracks)
• Multiple recurrent episodes requiring differentiation between true infection and carrier state

High-Risk Patients

In patients with high risk of rheumatic fever or severe symptoms, clinical judgment should be used, but antibiotics should generally still be withheld with negative tests. 2

Laboratory Findings

While bacterial pharyngitis may show TLC >12,000/mm³ with neutrophilia and left shift, whereas viral pharyngitis typically shows TLC <10,000/mm³ with relative lymphocytosis, laboratory values alone have poor sensitivity and specificity and should not guide antibiotic decisions without microbiological confirmation. 7