Pharyngitis, Acute Bacterial

Key Features

Essentials of Diagnosis

• Sore throat

• At least one of the following:

  • Cervical lymphadenopathy (lymph nodes tender or > 2 cm)

  • Tonsillar exudates

  • Positive culture showing group A β-hemolytic streptococci

  • Fever > 38.3°C

General Considerations

• Approximately 20–30% of children with pharyngitis have a group A streptococcal infection

• Most common in children between ages 5 and 15 years in the winter or early spring

• Causes include Mycoplasma pneumoniae, Chlamydia pneumoniae, groups C and G streptococci, and Arcanobacterium hemolyticum

• M pneumoniae is more common than other pathogens and may cause over one-third of all pharyngitis cases in adolescents and adults

Clinical Findings

Symptoms and Signs

• Sudden onset of sore throat, fever, tender cervical adenopathy, palatal petechiae, a beefy-red uvula, and a tonsillar exudate suggest streptococcal infection

• Other symptoms may include headache, stomachache, nausea, and vomiting

Differential Diagnosis

• Viral pharyngitis

• Infectious mononucleosis

• Bacterial pharyngitis other than streptococcal

• Diphtheria

• Peritonsillar abscess

Diagnosis

• Throat culture or rapid antigen test provide definitive diagnosis

• Rapid antigen tests are very specific, but have a sensitivity of only 85–95%

• Therefore, a positive test indicates S pyogenes infection, but a negative result requires confirmation by performing a culture

• The presence of conjunctivitis, cough, hoarseness, symptoms of upper respiratory infection, anterior stomatitis, ulcerative lesions, viral rash, and diarrhea should raise suspicion of a viral etiology

Treatment

• Suspected or proven group A streptococcal infection should be treated with

  • Penicillin V, 250 mg 2–3 times per day for 10 days if < 27 kg; 500 mg 2–3 times per day for 10 days if > 27 kg or

  • Benzathine penicillin, 600,000 units intramuscularly in single dose if < 27 kg; 1.2 million units intramuscularly in single dose if > 27 kg or

  • Amoxicillin 50 mg/kg/d once daily for 10 days (max 1200 mg)

• For patients allergic to penicillin, alternative treatments include

  • Cephalexin, 25–50 mg/kg/d in 2 divided doses for 10 days

  • Azithromycin, 12 mg/kg once daily for 5 days (max 500 mg/d)

  • Clindamycin, 20 mg/kg/d in 3 divided doses for 10 days

• For patients with recurrent streptococcal tonsillitis, tonsillectomy is preferred over daily penicillin prophylaxis because of concerns about drug resistance

Outcome

Follow-Up

• Repeat culture after treatment is not recommended and is indicated only for those who remain symptomatic, have a recurrence of symptoms, or have had rheumatic fever

• Of note, children who have had rheumatic fever are at a high risk for recurrence if future group A streptococcal infections are inadequately treated

• In this group of patients, long-term antibiotic prophylaxis is recommended, sometimes lifelong in patients with residual rheumatic heart disease

Complications

• Untreated streptococcal ...