What are the guidelines for the diagnosis and treatment of acute pharyngitis?

From the Guidelines

Guidelines for acute pharyngitis prioritize proper diagnosis and targeted treatment, with most cases being viral and requiring only symptomatic management, while suspected Group A Streptococcal (GAS) pharyngitis should be tested and treated with antibiotics like penicillin V or amoxicillin to prevent complications like rheumatic fever. The diagnosis of GAS pharyngitis should be established using rapid antigen detection tests or throat culture in patients with clinical features such as fever, tonsillar exudates, tender anterior cervical lymphadenopathy, and absence of cough 1.

Key Recommendations

• Testing for GAS pharyngitis is not recommended for children or adults with acute pharyngitis with clinical and epidemiological features that strongly suggest a viral etiology 1.
• For suspected GAS pharyngitis, first-line treatment is penicillin V (250-500 mg orally twice daily for 10 days for adults; 250 mg for children <27 kg and 500 mg for those >27 kg) or amoxicillin (50 mg/kg/day, max 1000 mg daily for 10 days) 1.
• Penicillin-allergic patients can be treated with alternatives like macrolides such as azithromycin (12 mg/kg/day, max 500 mg daily for 5 days) 1.
• Complete antibiotic courses are essential to prevent complications like rheumatic fever 1.
• Adjunctive treatments include salt water gargles, throat lozenges, and honey-based remedies for symptom relief.
• Patients should be advised to seek medical attention if symptoms worsen, persist beyond 7-10 days, or if they develop difficulty breathing or swallowing, as these may indicate complications requiring urgent care 1.

Important Considerations

• The role of Fusobacterium necrophorum in pharyngitis and subsequent development of Lemierre syndrome warrants further study, and clinicians should remain vigilant and suspect Lemierre syndrome in adolescent and young adult patients with severe pharyngitis 1.
• Routine testing for F necrophorum is not recommended, but urgent diagnosis and treatment of Lemierre syndrome is necessary to preclude complications and death 1.

From the FDA Drug Label

In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S. pyogenes) Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS): Three U. S. Streptococcal Pharyngitis Studies Azithromycin vs. Penicillin V EFFICACY RESULTS Day 14 Day 30 Bacteriologic Eradication: Azithromycin 323/340 (95%) 255/330 (77%) Penicillin V 242/332 (73%) 206/325 (63%) Clinical Success (Cure plus improvement): Azithromycin 336/343 (98%) 310/330 (94%) Penicillin V 284/338 (84%) 241/325 (74%)

The guidelines for acute pharyngitis recommend azithromycin as a treatment option, with a dosage of 12 mg/kg once a day for 5 days, which has been shown to be clinically and microbiologically superior to penicillin V at Day 14 and Day 30.

• Key points:
  • Azithromycin has a higher bacteriologic eradication rate than penicillin V at Day 14 (95% vs 73%) and Day 30 (77% vs 63%).
  • Azithromycin has a higher clinical success rate than penicillin V at Day 14 (98% vs 84%) and Day 30 (94% vs 74%).
  • The recommended dosage of azithromycin for pharyngitis is 12 mg/kg once a day for 5 days.
  • The incidence of treatment-related adverse events, primarily gastrointestinal, in all patients treated was 18% on azithromycin and 13% on penicillin 2. It is also important to note that amoxicillin can be used to treat pharyngitis caused by Streptococcus pyogenes, with a recommended dosage of 500 mg every 12 hours or 250 mg every 8 hours for adults, and 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours for pediatric patients aged 3 months and older and weight less than 40 kg 3.

From the Research

Diagnosis of Acute Pharyngitis

• The diagnosis of acute pharyngitis, particularly Group A beta-hemolytic streptococcal (GABHS) pharyngitis, cannot be reliably made based on clinical manifestations alone 4, 5, 6, 7, 8.
• Microbiologic testing, such as throat culture or rapid antigen detection test, is necessary to confirm the diagnosis of GABHS pharyngitis 4, 5, 6, 7, 8.
• Clinical score systems, such as the Centor score, can help clinicians decide which patients should undergo diagnostic testing and reduce the unnecessary use of antimicrobials 4, 8.

Treatment of Acute Pharyngitis

• The primary goal of treatment is to prevent suppurative and non-suppurative complications, alleviate symptoms, and reduce disease transmission 4, 5, 7.
• Oral penicillin V and amoxicillin are the recommended first-line therapies for GABHS pharyngitis 4, 5, 7, 8.
• Alternative treatments, such as cephalosporins, macrolides, and clindamycin, can be used in patients with penicillin allergy or treatment failure 4, 5, 7, 8.
• A 10-day course of antibiotic therapy is typically recommended, although some cephalosporins can be administered for a shorter duration 5, 7.

Rapid Antigen Detection Testing

• Rapid antigen detection tests can provide results in less than 15 minutes and have excellent specificity and sensitivity 6.
• A positive rapid antigen detection test is accepted as adequate for the diagnosis of GABHS pharyngitis, while a negative test may require confirmation with a throat culture 6, 7, 8.

Patient Education and Management

• Patient education can help reduce recurrence and improve adherence to treatment 7.
• Clinicians should consider patients' allergies, bacteriologic and clinical efficacy, frequency of administration, duration of therapy, potential side effects, compliance, and cost when selecting an antibiotic 7.