Pharyngitis

Background

• Pharyngitis (sore throat) is inflammation of the pharynx with or without tonsillitis or uvulitis, is diagnosed clinically and may be associated with infectious or noninfectious causes.
• Infectious causes include:
  • Viruses (the most common cause across age groups), which, in addition to those causing generalized upper respiratory infections, can include Epstein-Barr virus associated mononucleosis in adolescents and young adults, herpes simplex infections, and sometimes HIV.
  • Streptococcal pharyngitis, which the most common cause of acute bacterial pharyngitis, accounts for 20%-30% of cases of acute pharyngitis in children (with peak incidence in 5-11 year olds) and 5%-15% of cases in adults.
  • Less common bacterial causes of pharyngitis, which include Fusobacterium necrophorum, non-group A (group C or G) Streptococcus, and if sexually active, Neisseria gonorrhoeae.
  • Thrush (oral candidiasis), which can present with the classic white coating or with a more diffuse reddened appearance, and is often accompanied by tongue and palate involvement.
• Noninfectious causes are generally distinguished by lack of fever and longer duration (> 1-2 weeks) or recurrence. Common causes include gastroesophageal reflux disease (GERD), adenopathy from upper facial (ear or sinus) inflammation, and exposure to allergens or irritating inhaled or swallowed substances.

Evaluation

• Sore throat is typically characterized by pain, discomfort, and/or swelling of the throat or surrounding tissues. Sore throat is often, though not always, accompanied by other upper respiratory symptoms, which may help to identify potential etiology.
• The focus of the exam should be to differentiate group A Streptococcus (GAS) and COVID-19 from other causes of sore throat, and to recognize signs that may indicate more serious conditions.
• Group A Streptococcus may present with palatal petechiae, scarlatiniform rash, and vomiting (in children), but prediction models are validated to help decide which patients would benefit most from testing.
  • The Modified Centor/McIsaac criteria include fever, swollen anterior lymph nodes, tonsillar exudates, and lack of cough, also taking into account age < 45 (particularly 3-15 years of age).
  • The British FeverPAIN score is similar to the McIsaac score, but also considers the lack of nasal congestion and presentation at the medical office within 3 days of symptom onset.
  • Test patients with symptoms suggestive of group A streptococcal pharyngitis using rapid antigen detection test and/or throat culture (Strong recommendation).
  • Testing in children < 3 years old without risk factors, such as an older sibling with group A streptococcus, is not generally recommended.
  • Group C and G Streptococcus as well as Fusobacterium necrophorum can present almost identically to Group A Streptococcus, but these infections do not carry the risk of suppurative heart or renal complications.
  • Consider Neisseria gonorrhoeae in patients with a history of receptive oral sex.
• Testing for other diagnoses may include rapid antigen testing for COVID-19 and influenza and (when appropriate) heterophile antibody testing for infectious mononucleosis (Monospot). Viral etiology is strongly suggested by concomitant rhinorrhea, cough, hoarseness, diarrhea, oropharyngeal vesicles, and/or absence of fever, although COVID-19 and other viruses can present with sore throat alone.
• Consider throat culture in patients with negative rapid testing, particularly with worsening symptoms.
• Red flags that suggest a more serious etiology include dyspnea and stridor, vocal changes, trismus or asymmetric pain/findings in the pharynx or neck and severe systemic signs. Emergent evaluation is indicated for people with respiratory distress or threatened airway, which may include imaging once stabilized.
• A focal history of exposures (such as recent intubation, inhalation or ingestion of potential allergens or toxins, and newly started medications) as well as for gastroesophageal reflux disease (GERD) and/or other swallowing concerns is indicated when considering noninfectious causes.

Management

• Consider throat lozenges or nonsteroidal anti-inflammatory drugs (NSAIDs) for symptomatic relief.
• Corticosteroids, such as dexamethasone 10 mg orally as a 1 time dose, may hasten pain relief for acute pharyngitis; however, the use of corticosteroids, particularly in the setting of viral infections, remains a controversial area. See Steroids for Pharyngitis for additional information.
• Antibiotics are recommended for patients with group A streptococcal pharyngitis (Strong recommendation):
  • For patients without penicillin allergy, use penicillin or amoxicillin
    • Dosing of penicillin V
      • in children, 250 mg orally 2-3 times daily for 10 days
      • in adults and adolescents, 250 mg orally 4 times daily or 500 mg orally twice daily for 10 days
    • Dosing of amoxicillin is 50 mg/kg orally once daily (maximum 1,000 mg) or 25 mg/kg orally (500 mg maximum dose) twice daily for 10 days.
  • For patients with documented and/or confirmed penicillin allergy, use cephalexin, cefadroxil, azithromycin, clarithromycin, or clindamycin. See also Penicillin Allergy for assessment of patients with suspected allergy.
• Treat patients with gonococcal infection empirically for both Neisseria gonorrhoeae and, if not excluded, Chlamydia trachomatis with antibiotics (Strong recommendation).
• Deep soft tissue throat infections, such as peritonsillar or retropharyngeal abscess, acute epiglottitis or Lemierre syndrome, are indications for urgent evaluation and/or management, sometimes including stabilization, imaging, ear-nose-throat (ENT) consultation, and procedures and/or antibiotics.
• Consider tonsillectomy for patients with recurrent throat infection characterized by any of the following (Weak recommendation):
  • ≥ 7 pharyngotonsillitis episodes in past year
  • ≥ 5 pharyngotonsillitis episodes per year for 2 years
  • ≥ 3 pharyngotonsillitis episodes per year for 3 years