Pharyngitis
BASICS
DESCRIPTION
- Acute or chronic inflammation of the pharyngeal mucosa
- Group A Streptococcus (GAS) pharyngitis is notable for preventable suppurative (e.g., retropharyngeal or peritonsillar abscess) and nonsuppurative (e.g., rheumatic sequelae) complications
- Synonyms: sore throat; tonsillitis; “strep throat”
EPIDEMIOLOGY
- ~15 million cases diagnosed yearly.
- 1–2% of all outpatient and 6% of all pediatric visits to primary care physicians
- ~50% of cases of acute pharyngitis occur <18 years of age, and incidence declines in adults >40 years of age
- Most commonly viral (50–80% of cases)
- GAS is the most common bacterial cause of acute pharyngitis, accounting for 15–30% of pediatric cases (with peak incidence in 5 to 11 years old) and 5–15% of adult cases
- Less common causes of pharyngitis include Fusobacterium necrophorum, nongroup A Streptococcus, and Neisseria gonorrhoeae if sexually active
- Rheumatic fever is a serious sequela but is rare in the United States (<1 case per 100,000). Early antibiotic use has reduced occurrence.
- 3,000 to 4,000 patients with GAS must be treated to prevent one case of acute rheumatic fever.
Pediatric Considerations
The highest incidence of rheumatic fever is in children 5 to 18 years as a rare sequelae of streptococcal pharyngitis.
ETIOLOGY AND PATHOPHYSIOLOGY
- Acute, viral (associated with lower grade fever)
- Most common pathogens: rhinovirus; adenovirus; coronavirus; enterovirus; influenza; parainfluenza virus; coxsackievirus; respiratory syncytial virus
- Less common pathogens: herpes simplex virus; Epstein-Barr virus (EBV); cytomegalovirus (CMV); HIV
- Acute, bacterial (associated with higher fevers)
- N. gonorrhoeae; Corynebacterium diphtheriae (diphtheria); Haemophilus influenzae
- Moraxella catarrhalis; Chlamydia pneumonia
- Fusobacterium necrophorum (20% young adult cases); group C or G Streptococcus
- Arcanobacterium haemolyticum; Mycoplasma pneumoniae; Francisella tularensis (tularemia)
- Acute, noninfectious
- Maybe caustic, mechanical, or trauma-related
- Chronic, more likely noninfectious
- Allergic rhinitis
- Gastroesophageal reflux disease (GERD)
- Smoking or smoke exposure
- Dry air exposure
- Vocal strain
- Medication side effects
- Neoplasms
- Vasculitis
- Radiation
Genetics
Patients with family history of rheumatic fever have a higher risk of rheumatic sequelae following an untreated GAS infection.
RISK FACTORS
- Epidemics of GAS
- Cold season (late fall through early spring)
- Age (rheumatic fever possible, especially in children/adolescents 5 to 15 years)
- Close contact with infected people (home, daycare, barracks)
- Immunosuppression
- Smoking or smoke exposure
- Allergic rhinitis
- GERD
- Oral sex
- Diabetes mellitus
- Recent illness
- Chronic colonization of bacteria in tonsils/adenoids
GENERAL PREVENTION
- Avoid close contact with infectious people
- Wash hands frequently
- Vaccinations
- Avoid smoking or secondhand smoke
- Manage preventable causes (e.g., GERD, allergic rhinitis)
DIAGNOSIS
Diagnosis is clinical, but suspicion for bacterial cause may warrant testing based on prediction rules
HISTORY
- Sore throat
- Dysphagia/odynophagia
- Cough (uncommon in GAS pharyngitis)
- Rhinorrhea
- Conjunctivitis
- Hoarseness; muffled or “hot potato” voice
- Fever
- Anorexia
- Chills
- Malaise; fatigue
- Headache
- Dysuria and arthralgias (suggest gonococcal etiology)
- Sick contacts with similar symptoms or confirmed diagnosis
PHYSICAL EXAM
- Enlarged tonsils with or without exudate
- Pharyngeal erythema; palatal petechiae
- Unilateral tonsillar swelling or uvular deviation (concern for peritonsillar abscess)
- Trismus; stridor; drooling (concern for peritonsillar/retropharyngeal abscess or epiglottitis)
- Neck stiffness or pain with neck extension (concerning for retropharyngeal abscess)
- Cervical adenopathy (anterior suggestive of GAS, posterior associated with infectious mononucleosis)
- Fever (higher in bacterial infections)
- Pharyngeal ulcers (CMV, HIV, Crohn disease, other autoimmune vasculitides)
- Scarlet fever rash: punctate erythematous macules with reddened flexor creases and circumoral pallor suggests GAS
- Tonsillar/soft palate petechiae with hepatosplenomegaly suggest infectious mononucleosis (EBV/CMV)
- Gray oral pseudomembrane suggests diphtheria or infectious mononucleosis (EBV/CMV)
- Characteristic erythematous-based clear vesicles suggest HSV or coxsackie A virus infection (herpangina).
- Conjunctivitis suggests adenovirus.
DIFFERENTIAL DIAGNOSIS
- Viral infection, including acute HIV, EBV, and CMV infection
- Streptococcal infection
- Allergic rhinitis
- GERD
- Malignancy (lymphoma or squamous cell carcinoma)
- Irritants/chemicals (detergent/caustic ingestion)
- Atypical bacterial (e.g., gonococcal, chlamydial, syphilis, pertussis, diphtheria)
- Oral candidiasis (patients typically complain of dysphagia)
- Thyroiditis (can be painful or painless, possibly associated with hyperthyroid syndrome)
- Epiglottitis (associated with stridor, drooling, and respiratory distress)
- Referral from extrapharyngeal source (e.g., otitis media, dental abscess)
- Foreign body
DIAGNOSTIC TESTS & INTERPRETATION
- Prediction rules determine need for further testing (see below).
- Testing is generally not needed with overt viral clinical features (e.g., cough, rhinorrhea, hoarseness, oral ulcers) (1)[ ]
- Avoid testing for GAS pharyngitis in children <3 years as acute rheumatic flare is rare, unless there is a close sick contact who is GAS-positive (1)[ ].
- Modified Centor clinical prediction rule for GAS infection:
- +1 point: tonsillar exudates or swelling
- +1 point: tender anterior chain cervical adenopathy
- +1 point: absence of cough
- +1 point: fever by history
- +1 point: age <15 years
- 0 point: age 15 to 44 years
- −1 point: age >44 years
- Scoring:
- 4 points: positive predictive value ~80%; treat empirically
- 2 to 3 points: positive predictive value ~50%, rapid strep antigen; treat if GAS-positive
- 0 or 1 point: positive predictive value <20%; do not test; treat symptomatically with follow-up as needed
Initial Tests (lab, imaging)
- Testing is usually for GAS, as clinical features do not reliably discriminate between GAS and viral etiologies. Options include:
- Rapid antigen detection test (RADT); quick adjunct to throat culture with 96% specificity and 86% sensitivity (though sensitivity varies by modality kit) (2)[ ]
- Diagnostic testing of asymptomatic contacts not routinely recommended
- Blood agar throat culture from swab; gold standard (90–95% sensitivity) (2)[ ]
- Throat cultures are not needed for adults with negative RADT. They are recommended for children with negative RADT due to the higher likelihood of complications but can be omitted if a highly sensitive immunoassay or molecular test is used
- Antistreptolysin O titer test is not recommended for diagnosis
- Other tests if history suggests a different diagnosis
- NAAT (N. gonorrhoeae)
- Viral cultures (HSV)
- Monospot (EBV)
- IgM serology (CMV)
- HIV viral load
- Imaging may be indicated if sequelae of pharyngitis such as retropharyngeal abscess are suspected
Follow-Up Tests & Special Considerations
- Assess for signs of severe infection, such as muffled voice, stridor, or respiratory distress as this may indicate impending airway compromise requiring immediate stabilization or transfer to higher level of care
- Recurrent GAS infection may indicate β-lactamase production by host and may require anti-β-lactamase therapy.
Test Interpretation
Bacitracin disk sensitivity of hemolytic colonies suggests GAS
TREATMENT
Treatment is aimed for symptomatic relief, unless bacterial infection is suspected or confirmed.
GENERAL MEASURES
Conservative therapy recommended for viral cases:
- Salt water gargles
- Acetaminophen 10 to 15 mg/kg/dose q4h PRN (pediatric). In adults, do not exceed >4 g/day
- Non-steroidal anti-inflammatory drugs (NSAIDs) are more effective than acetaminophen for GAS pharyngitis
- Single-dose corticosteroids may be effective in reducing symptom severity, though data is limited
- Anesthetic lozenges
- Cool-mist humidifier
- Hydration (PO or IV if PO is not tolerated)
- Viscous lidocaine (2%) 5 to 10 mL PO q4h swish/spit (severe pain)
Pediatric Treatment Considerations
- Opioids are not recommended due to black box warnings.
- Lower threshold to start antibiotics given higher risk of rheumatic fever.
- Avoid aspirin in pediatric patients given risk of Reye syndrome.
MEDICATION
- Antibiotics are used primarily to prevent complications of GAS.
- 60–70% primary care visits by children with pharyngitis result in antibiotic prescriptions, contributing to antibiotic overuse (3)
- Antibiotics minimally reduce risk of poststreptococcal glomerulonephritis.
- Antibiotics shorten symptom duration by ~16 hours
- Antibiotics may prevent pharyngitis/fever by day 3 (NNT 4 if GAS-positive, 6.5 if GAS-negative, 14.4 if untested).
- Ulcers related to autoimmunity often require systemic or intralesional steroids.
- HIV-related ulcers are due to decreasing CD4 count and respond when CD4 titers increase.
First Line
- Penicillin V: children (<27 kg): 250 mg PO TID (BID dosing sufficient if compliant); adolescents and adults (>27 kg): 250 mg PO QID or 500 mg PO BID for 10 days
- Penicillin G benzathine: children <60 lb (27 kg): 600,000 units intramuscularly 1 dose; children ≥60 lb and adults (≥27 kg): 1.2 million units intramuscularly 1 dose
- Amoxicillin: 50 mg/kg PO once daily (max 1,000 mg/dose) or 25 mg/kg PO BID (max of 500 mg/dose) for 10 days
Use with caution if unclear diagnosis because using amoxicillin with EBV infection may induce rash.
Second Line
- If type IV hypersensitivity without anaphylactic penicillin allergy:
- Cephalexin 20 mg/kg PO BID or (children) 25 to 50 mg/kg/day divided BID or (adults) 1,000 mg PO QID (max of 4 g/day) for 10 days
- Cefadroxil 30 mg/kg PO once daily (max of 1 g/day) for 10 days
- If history of anaphylactic penicillin allergy (type I hypersensitivity):
- Azithromycin 12 mg/kg PO once daily (max of 500 mg/dose), then 6 mg/kg (max of 250 mg/dose) once daily for 4 days after
- Clarithromycin 7.5 mg/kg PO BID (max of 250 mg/dose) or (adults) 250 to 500 mg PO BID for 10 days
- Clindamycin 7 mg/kg PO TID (max of 300 mg/dose) or (children) 10 to 30 mg/kg/day PO divided TID–QID or (adults) 150 to 450 mg PO TID–QID for 10 days
- Penicillin is most commonly used to prevent rheumatic sequelae; cephalosporins have a lower rate of failure for streptococcal pharyngitis.
- For children with lab-confirmed recurrence of GAS pharyngitis, treatment can include a previously utilized agent.
ISSUES FOR REFERRAL
- Document GAS-confirmed episodes to support need for future tonsillectomy/adenoidectomy.
- Tonsillectomy is recommended for those who have had seven or more throat infections in 1 year, five or more infections/year for the past 2 years, or three or more infections/year for the past 3 years.
- Tonsillectomy is also recommended in patients who are difficult to treat medically, such as those with allergies to many antibiotics or history of peritonsillar abscess.
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
- Finish antibiotic course regardless of symptom response.
- Patients are generally noninfectious after 24 hours of antibiotics.
- Follow-up culture for GAS is not recommended (1)[ ].
DIET
As tolerated; ice, tea, soups, and honey may be used for symptoms relief with adequate fluid intake.
PROGNOSIS
- Acute viral and bacterial infections are typically self-limited to 5 to 7 days.
- GAS symptoms resolve without treatment, but rheumatic complications are still possible.
- Treatment failures (symptoms >10 days) may be due to antibiotic resistance, poor compliance, or untreated contacts
- Without confounding factors, prolonged symptoms should prompt work up for alternative cause
COMPLICATIONS
- Rheumatic fever (e.g., carditis, valve disease, arthritis)
- Poststreptococcal glomerulonephritis
- Peritonsillar abscess: considered a clinical diagnosis and does not warrant imaging
- Generally requires percutaneous/transoral drainage
- Treatment may involve tonsillectomy, but most sources recommend resolution of infection before surgery.
- Acute airway compromise can often be bypassed with nasal trumpets; consult anesthesiologist/otolaryngologist.
- Repeated positive GAS tests may represent a chronic carrier of GAS. Use of antibiotics to treat GAS carriage is not recommended as risk of complications and transmission is low (1)[ ].
Authors
Munima Nasir, MD
Zakary S. Newberry, MD
REFERENCES
- et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis. 2012;55(10):1279–1282. [PMID:23091044] , , ,
- [PMID:34336062] , , . Group A streptococcal pharyngitis: A practical guide to diagnosis and treatment. Paediatr Child Health. 2021;26(5):319–320.
- [PMID:33828608] . Paediatrics: how to manage pharyngitis in an era of increasing antimicrobial resistance. Drugs Context. 2021;10:2020-11-6.
ADDITIONAL READING
et al. Pharyngitis: approach to diagnosis and treatment. Can Fam Physician. 2020;66(4):251–257. [PMID:32273409] , , ,
SEE ALSO
- Herpes Simplex; Infectious Mononucleosis, Epstein-Barr Virus Infections; Rheumatic Fever
- Algorithm: Pharyngitis
CODES
ICD10
- J31.1 Chronic nasopharyngitis
- A54.5 Gonococcal pharyngitis
- B08.5 Enteroviral vesicular pharyngitis
- A56.4 Chlamydial infection of pharynx
- J02.9 Acute pharyngitis, unspecified
- J02 Acute pharyngitis
- J31 Chronic rhinitis, nasopharyngitis and pharyngitis
- A50.03 Early congenital syphilitic pharyngitis
- J02.0 Streptococcal pharyngitis
- J31.2 Chronic pharyngitis
- J02.8 Acute pharyngitis due to other specified organisms
SNOMED
- 232403001 Chlamydial pharyngitis
- 195660001 Acute staphylococcal pharyngitis
- 195658003 Acute bacterial pharyngitis
- 312422001 Infective pharyngitis
- 363746003 Acute pharyngitis
- 405737000 Pharyngitis
- 195663004 Allergic pharyngitis
- 1532007 Viral pharyngitis
- 140004 Chronic pharyngitis
- 39271004 Ulcerative pharyngitis
- 78430008 Adenoviral pharyngitis
- 74372003 Gonorrhea of pharynx
- 43878008 Streptococcal sore throat
- 58031004 Suppurative pharyngitis
- 232402006 Meningococcal pharyngitis
- 195662009 Acute viral pharyngitis
- 195924009 Influenza with pharyngitis
- 195780008 Pharyngitis sicca
- 195782000 Chronic follicular pharyngitis
CLINICAL PEARLS
- Most cases of pharyngitis are viral and do not require antibiotics.
- The risk associated with undiagnosed and untreated GAS is rheumatic sequelae.
- Use of the Modified Centor Score helps to guide testing and treatment.
- Penicillin is the preferred first-line therapy for GAS infection.
Last Updated: 2026
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