Continuing Education Activity

Streptococcal pharyngitis, commonly known as "strep throat," is a bacterial throat infection caused by Streptococcus pyogenes (group A streptococcus). It typically presents with a sudden onset of sore throat, fever, pharyngeal inflammation, and tender cervical lymph nodes. Key findings include tonsillar exudate, palatal petechiae, and uvular edema. Although most common in children aged 3 to 9, streptococcal pharyngitis can occur in adolescents and adults, albeit at lower rates. A sore throat accompanied by cough, rhinorrhea, or hoarseness suggests a viral cause but does not exclude streptococcal pharyngitis.

Accurate diagnosis requires a combination of clinical decision rules and rapid antigen detection testing (RADT), as history and physical exams alone are insufficient. In addition to supportive care, antibiotics are first-line treatments for confirmed cases to reduce symptom duration and prevent complications. Preventive measures are critical to reducing transmission, especially in close-contact environments. This activity for healthcare professionals is designed to enhance the learner's competence in applying clinical decision criteria to evaluate suspected streptococcal pharyngitis appropriately, institute antibiotic stewardship, and implement an appropriate interprofessional management approach to improve patient outcomes.

Objectives:

• Identify the clinical indications for group A streptococcal pharyngitis testing.
•  Evaluate patients with suspected group A streptococcal pharyngitis according to recommended diagnostic guidelines.
• Implement the appropriate management for patients with group A streptococcal pharyngitis.
• Apply interprofessional team strategies to improve care coordination and outcomes in patients with group A streptococcal pharyngitis.

Introduction

Streptococcal pharyngitis, also known as group A streptococcus (GAS) pharyngitis, or colloquially as "strep throat," is a common condition caused by pharyngeal infection by the bacteria Streptococcus pyogenes. Streptococcal pharyngitis frequently presents with a painful sore throat, an abrupt onset fever, and recent sick contacts. The highest incidence of streptococcal pharyngitis occurs among children 3 to 9 years of age, followed by adolescents 10 to 19.[1] Incidence in adults is far lower, and of adult patients seeking care for sore throat, only 10% to 15% will have streptococcal pharyngitis, yet 60% or more of those adult patients will receive prescriptions for antibiotics.[2]

Etiology

Streptococcus pyogenes, or GAS, is a facultative anaerobic gram-positive coccus that appears in fine chains on gram-stain material.

Epidemiology

Streptococcal pharyngitis (GAS pharyngitis) is the most common bacterial cause of pharyngitis in children and adolescents, with a peak incidence in winter and early spring, and is also more common in those with a direct relation to school-aged children.[3] The incidence of streptococcal pharyngitis declines dramatically from its peak among school-age children to middle-aged and older adults, with 93.2 cases per 1000 person-years at risk (PYAR) among children aged 3 to 9 years, 40.9 cases per 1000 PYAR in children aged 10 to 19, 8 cases per 1000 PYAR among adults aged 20 to 39, and only 1.1 cases per 1000 PYAR for adults 40 to 65 years of age.[1]

History and Physical

Clinical Features of Streptococcal Pharyngitis

Multiple studies have shown that history and physical examination alone fail to aid clinicians in accurately diagnosing GAS pharyngitis.[4] However, a history of a sore throat, abrupt onset of fever, the absence of a cough, and exposure to someone with GAS pharyngitis within the previous 2 weeks may suggest GAS pharyngitis.[5][6] Additional physical exam findings include tender cervical lymphadenopathy, pharyngeal inflammation, and tonsillar exudate. Palatal petechiae and uvular edema are also suggestive.[5][6]

Symptoms of viral illness, like cough, rhinorrhea, or hoarseness, reduce the likelihood of streptococcal pharyngitis but cannot rule it out.[2] In a 2020 national validation study, 37.6% of patients presenting with sore throat tested positive for streptococcal pharyngitis; patients with ≥1 viral symptom had a test positivity rate of 28.3%, and patients with all 3 viral symptoms tested positively at a rate of 23.2%.[7]

Evaluation

The Infectious Disease Society of America (IDSA) notes that a diagnosis of GAS pharyngitis cannot be made based on history and physical alone.[8] Various clinical scoring systems have been developed to assist clinicians with streptococcal pharyngitis diagnosis. Clinicians should utilize clinical decision rules, which assist in determining a patient's risk of having streptococcal pharyngitis (see Table. Streptococcal Pharyngitis Clinical Decision Rules), as a prediction tool to help guide management. This risk stratification, combined with rapid antigen detection testing (RADT), improves diagnostic accuracy and reduces unnecessary antibiotic use.[2][9]

Patients at intermediate or high risk on a clinical decision rule should receive RADT; patients at low risk based on a clinical decision rule do not need any further testing for GAS pharyngitis.[2] Patients evaluated using telemedicine and scoring a 0 or 1 with either Centor or McIsaac can safely be considered low-risk and do not need in-person evaluation.[10] Rapid antigen testing may be omitted for children younger than 3 years due to the low risk of both GAS pharyngitis and rheumatic fever in this age group.[8] The exception is a child younger than 3 with a young sibling with confirmed GAS pharyngitis.[8]

A throat culture may be performed in children with a negative RADT, as recommended by the American Academy of Pediatrics Red Book 2025 update. However, previous papers have argued that subsequent throat cultures were not cost-effective for preventing childhood rheumatic fever.[2]

Anti-streptococcal antibody titers are not recommended because results reflect previous infections. Following treatment, a test of cure is not needed but may be considered in special circumstances.[8]

Table

Table. Streptococcal Pharyngitis Clinical Decision Rules.

Treatment / Management

Antibiotics are indicated in a patient with confirmed streptococcal pharyngitis. Patients with a high-risk Centor or McIsaac score without a positive RADT may also be treated empirically with antibiotics if the test is unavailable.[2] The recommended first-line antibiotics are penicillin or amoxicillin, and a first-generation cephalosporin may be used if the patient has a nonanaphylactic reaction to β-lactams. A macrolide or clindamycin may be utilized in a patient with a known anaphylactic reaction to β-lactam antibiotics.[8][2] 

If a patient's symptoms do not improve within 5 days or improve before worsening again, the patient should be reevaluated.[2][13] Broad-spectrum antibiotics do not reduce the risk of treatment failure.[14]

Antibiotic Treatment Regimens

Patients without allergies to β-lactam antibiotics should receive one of the following recommended amoxicillin or penicillin treatment regimens:

• Amoxicillin: Children: 50 mg per kg per day orally (maximum: 1,000 mg per day) for 10 days or 50 mg/kg (max 500 mg) twice daily orally for 10 days
• Penicillin V

  • Children: 250 mg orally 2 to 3 times per day for 10 days
  • Adolescents and adults: 250 mg orally 4 times daily, or 500 mg orally twice daily for 10 days
• Benzathine penicillin G

  • Individuals weighing <27 kg: 600,000 units intramuscularly (IM)
  • Individuals weighing ≥27 kg: 1,200,000 units IM

Patients with allergies to penicillin should receive one of the following alternative treatments, though immediate-type hypersensitivities should not be given cephalexin or cefadroxil:

• Cephalexin: 20 mg per kg orally twice per day (maximum 500 mg per dose) for 10 days
• Cefadroxil: 30 mg per kg once daily (maximum 1 g daily) for 10 days
• Azithromycin: 12 mg per kg orally on day 1 (maximum 500 mg), then 6 mg per kg (max 250 mg) orally once per day for days 2 through 5
• Clarithromycin: 7.7 mg per kg orally twice per day (max 250 mg per dose) for 10 days
• Clindamycin: 20 mg per kg per day orally (max 900 mg per day) divided into 3 doses for 10 days [2][15][16]

Streptococcus pyogenes resistance to azithromycin, clarithromycin, and clindamycin has been documented widely. Therefore, clinicians should be aware of local resistance patterns.[CDC, Clinical Guidance for Group A Streptococcal Pharyngitis] 

As adjunctive therapy for the patient with GAS pharyngitis, the IDSA recommends acetaminophen or an NSAID to control pain associated with the disease or any fever that should develop. Currently, the IDSA does not recommend routine adjunctive therapy with corticosteroids for those with GAS pharyngitis.[8]

Posttreatment and Prevention Recommendations

Following antibiotic treatment, patients may see symptoms resolve within 1 to 3 days and return to work or school after 24 hours. However, a test of cure is not recommended after a course of treatment unless the patient has a history of acute rheumatic fever or another GAS complication. 

Likewise, postexposure prophylaxis is not recommended unless a patient has a history of acute rheumatic fever, during outbreaks of nonsupportive complications, or when GAS infections are seen recurrently in households or close contacts. Disease prevention is achieved through proper hand hygiene, which is also key to halting disease progression within close quarters.[8]

Differential Diagnosis

Infectious and noninfectious differential diagnoses that should also be considered during the evaluation of streptococcal pharyngitis include:

• Infectious causes

  • Viral upper respiratory infection 
  • COVID-19
  • Lemierre's Syndrome (Fusobacterium necrophorum) 
  • Acute HIV infection
  • Epstein-Barr virus
  • Neisseria gonorrhoeae
  • Treponema pallidum [8][2]

• Noninfectious causes

  • Allergies
  • Gastroesophageal reflux disease
  • Exposure to second-hand smoke
  • Trauma
  • Autoimmune disorders (eg, Behçet syndrome and Kawasaki)
  • Foreign body [8]

Prognosis

Streptococcal pharyngitis is a self-limited illness for most patients in the United States.[8] Still, roughly 10% will experience treatment failure or relapse.[17] Suppurative complications and nonsuppurative complications are rare.[2]

Complications

Nonsuppurative complications of streptococcal pharyngitis include poststreptococcal glomerulonephritis and acute rheumatic fever. The incidence of acute rheumatic fever in the United States is exceedingly low, with only 0.5 cases per 100,000, though the rates in developing countries have been estimated at 8 to 51 per 100,000.[18] Classic symptoms of acute rheumatic fever include the JONES major criteria: arthralgia, carditis, subcutaneous nodules, erythema marginatum, and chorea.[19] 

Suppurative complications seen with GAS pharyngitis occur in roughly 1% of patients and include tonsillopharyngeal cellulitis or abscess, otitis media, sinusitis, necrotizing fasciitis, bacteremia, meningitis, brain abscess, jugular vein septic thrombophlebitis.[20]

Consultations

Tonsillectomy as a treatment for recurrent streptococcal pharyngitis is recommended in limited circumstances. Patients may benefit from surgical intervention if they meet thresholds for recurrent infections: 7 episodes in the previous year, 5 episodes per year for the previous 2 years, or 3 episodes per year for the previous 3 years.[21][22][23] Other modifying factors may indicate a need for an otolaryngology consult, including multiple antibiotic allergies or intolerance, a history of peritonsillar abscess, or PFAPA symptoms (ie, periodic fever, aphthous stomatitis, pharyngitis, and adenitis).[24]

Deterrence and Patient Education

Regular handwashing and respiratory etiquette will reduce the spread of streptococcal pharyngitis. Patients suffering from GAS pharyngitis should stay home from school or work until they are both afebrile and have been on antibiotics for at least 12 to 24 hours.[CDC, Clinical Guidance for Group A Streptococcal Pharyngitis]

Pearls and Other Issues

Clinicians should bear in mind the following key factors regarding streptococcal pharyngitis:

• The rapid antigen detection test (RADT) should be the primary diagnostic modality, regardless of whether the clinician employs the Centor or McIsaac clinical decision rules for risk stratification. RADT is highly specific for streptococcal pharyngitis. 
• The treatment of choice for confirmed GAS pharyngitis is either penicillin or amoxicillin. For those with an allergy to penicillin, then cephalexin, macrolides, or clindamycin may be used, depending on the patient's allergy.
• Broad-spectrum antibiotics do not reduce the rate of treatment failure. 
• In telehealth evaluations, a patient with a 0 or 1 Centor or McIsaac score does not need an in-person evaluation and can be treated with supportive care. 

Enhancing Healthcare Team Outcomes

The diagnosis and management of streptococcal pharyngitis are most effective when supported by an interprofessional healthcare team. Primary care clinicians, emergency physicians, nurse practitioners, and otolaryngologists are central to evaluating symptoms, employing clinical decision rules, and utilizing RADT to confirm diagnoses. Nurses are crucial in patient education, assisting with diagnostic procedures, and reinforcing adherence to prescribed treatments. Pharmacists ensure that antibiotics are appropriately selected, provide medication counseling, and address potential resistance concerns. Laboratory professionals are integral to providing timely and accurate diagnostic results, while infectious disease specialists and internists offer guidance for complex or recurrent cases.

Clear communication and care coordination among team members are critical to optimizing patient-centered care and improving outcomes. Educating patients on proper hand hygiene and the importance of completing prescribed treatments helps prevent the spread of infection and minimizes complications. Patients should also be informed about the small risk of developing conditions such as glomerulonephritis or rheumatic fever. Through collaborative efforts, the healthcare team ensures timely treatment, reduces the duration and severity of symptoms, and promotes a safer, faster recovery, ultimately enhancing both individual patient safety and public health.

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Disclosure: John Ashurst declares no relevant financial relationships with ineligible companies.

Disclosure: Ethan Weiss declares no relevant financial relationships with ineligible companies.

Disclosure: Debbie Tristram declares no relevant financial relationships with ineligible companies.

Disclosure: Laura Edgerley-Gibb declares no relevant financial relationships with ineligible companies.