Resident Editor: Karen Anstey, MD

Faculty Editor: Paul Nadler, MD

BOTTOM LINE ✔ Antibiotics are NOT indicated in the majority. ✔ Centor criteria are helpful in determining the likelihood of Group A strep pharyngitis, guiding evaluation and treatment. ✔ Essentially no role for routine GAS culture in the initial evaluation of adult pharyngitis.

Background

• Very common primary care complaint, accounting for >10 million ambulatory visits annually
• Group A Strep is the major treatable pathogen, although this accounts for a minority of cases
• The main goal of evaluation is to identify patients for whom antibiotics are appropriate (i.e., those most likely to have Group A strep)

Group A streptococcus (GAS) pharyngitis

• Accounts for only 5-15% of pharyngitis in adults
• *Centor Criteria for clinical diagnosis of GAS pharyngitis

  Fever (>100.4) Tender anterior cervical lymphadenopathy Tonsillar exudate Absence of cough *modified Centor Criteria: subtract 1 point for age >44

• Other symptoms and signs include: odynophagia, mild neck stiffness, malaise, anorexia, headache, myalgias, tonsillopharyngeal inflammation/injection, scarlatiniform rash, strawberry tongue
• See treatment section below for application of Centor Criteria
• Complications: Peritonsillar abscess, otitis media, sinusitis, meningitis, poststreptococcal glomerulonephritis, rheumatic fever, reactive arthritis

Differential diagnosis

• Other infectious agents account for the majority of cases of pharyngitis
  • Viruses (most common), including influenza and parainfluenza (~30-50% of cases)
  • Acute HIV: Causes painful mucocutaneous lesions, fever, lymphadenopathy
  • EBV (mononucleosis syndrome): prodrome of fevers, chills, sweats, and marked malaise, followed by the classic triad of severe sore throat, lymphadenopathy (posterior/anterior cervical, axillary, inguinal), and splenomegaly
  • HSV (~4%)
  • Other bacteria: Group C or G strep (~5%, up to 25% of severe pharyngitis; not tested for by RADT), gonorrhea (<1%), diphtheria (<1%), anaerobes
  • Non-infectious causes: allergen or irritant, postnasal drip, reflux, etc.

 

Evaluation

• Rapid direct GAS antigen detection (RADT): sensitivity ~90%, specificity >95%
• Throat culture: >90% sensitive; takes 24-48 hrs. to result; no longer indicated in the initial evaluation of adults given the high sensitivity/specificity of newest RADT. Routine throat culture for negative RADT no longer recommended in adults (but should be considered in those who are immunocompromised, taking care of those who are immunocompromised, or living in areas where the prevalence of GAS is high i.e. college dormitories)
• Testing for acute HIV (HIV Ag/Ab & viral load), gonorrhea (swab), and syphilis in high-risk populations

Treatment

A. When to consider treatment with antibiotics

The rationale for treating Group A strep pharyngitis with antibiotics

• Reduces the duration of symptoms by 1-2 days (if started within 48-72 hrs. of sx onset)
• Reduces period of contagion (to 24 hours after starting treatment)
• Decreases incidence of suppurative complications
• Prevents rheumatic fever, if started within ~10 days of symptom onset (estimated that need to treat 3-4,000 GAS pharyngitis cases in the US to prevent 1 case of rheumatic fever)
• Treatment with antibiotics does NOT prevent post-strep GN
• Three treatment algorithms based on the Centor Criteria for immunocompetent adults
  • *In all, if 1 or fewer criteria met, no further testing needed to treat symptomatically
  • *Most agree upon test and treat for a score of 2
  • *What to do with a score of 3-4 is still controversial (test and treat vs. empiric treatment)
    • Algorithm 1 minimizes antibiotic use (and theoretically resistance) and potential for adverse effects; algorithms 2 & 3 prioritize relieving symptoms in severe pharyngitis, also will tx non-GAS bacterial pharyngitis cases, and may reduce suppurative complications
    • Note that other bacteria (group C, G strep, and anaerobes) cause a proportion of pharyngitis and are not detected on rapid GAS antigen testing. Algorithms 1 & 2 will leave untreated those cases caused by other bacteria. Empiric antibiotics would likely prevent some suppurative complications or transmissions beyond those prevented when treating only rapid GAS (+) patients
    • Note that even if all 4 Centor criteria met, the probability of GAS is <60%

Diagnostic and Treatment Approaches to Acute Pharyngitis Using Centor Criteria (ACP-ASIM)

1. >2 Centor score, test using RDAT   if (+), treat with antibiotics.         (IDSA endorsed)

OR

2. >2 or 3 Centor score, perform rapid GAS antigen test and treat if (+); if Centor score of 4 present, treat empirically with antibiotics

OR

3. Empirically treat all patients with a Centor score of 3 or 4 without testing any

B. Treatment for GAS Pharyngitis:

• Penicillin 500mg PO BID (or TID) x 10 days (apart from meals) or UCSF IDMP recommends penicillin 250mg TID-QID for 10 days
• Amoxicillin 1g PO once daily or 500mg BID x 10 days
• If PCN allergy, UCSF IDMP recommends using clindamycin 300 mg PO TID x 7-10 days; IDSA recommends using Clindamycin x 10 days vs Keflex x 10 days (if no anaphylaxis to PCN) vs Clarithromycin x 10 days vs Azithromycin x 5 days. The CDC recommends erythromycin
• IDSA strongly recommends against tonsillectomy for recurrent GAS

 

C. Symptomatic Treatment

• Salt-water gargle (1/2 tsp per 8 oz. or 1 tsp salt in quart warm water), rest, fluids
• OTC topical anesthetic lozenges, sprays (i.e. Cepacol brand)
• Anti-inflammatory (i.e.  NSAID)
• Antipyretic (e.g., acetaminophen) 
• If severe, consider viscous lidocaine or Magic Mouthwash gargle (1:1:1 ratio of Benadryl, Maalox, viscous lidocaine) or limited opiates

 

When To Refer/Seek Higher Level of Care:

Warning symptoms: Very severe sore throat  difficulty swallowing, esp. if difficulty swallowing secretions; drooling, pooling of secretions, dysphonia or hot potato/muffled voice, neck swelling, trismus, stridor or shortness of breath; worsening of sore throat or persistence > 5 days

 

Diagnoses to consider if the above symptoms are present:

• Peritonsillar Abscess (PTA): Especially consider if trismus and severe unilateral throat and neck pain +/- swelling, uvular deviation
• Retropharyngeal Abscess (RPA): Similar to PTA but lower in the neck and more often related to penetrating trauma (e.g. chicken bone)
• Ludwig’s Angina (Submandibular space infection): Tender firm induration of submandibular space often with a raised red tender floor of oropharynx
• Epiglottitis: Consider particularly if stridor, drooling, and hot potato voice
• Lemierre’s Syndrome (IJ Thrombophlebitis 2/2 fusobacterium)

 

References:

Bailey BJ, Johnson JT, Newlands SD, et al. Head, and Neck Surgery – Otolaryngology, Fourth Edition.  Lippincott Williams and Wilkins, 2006.

Bisno, A. Acute Pharyngitis. NEJM. 2001; 344: 205-211.

Centers for Disease Control and Prevention. Acute Pharyngitis in Adults. 2014. 

Centor, RM, Allison, J, Cohen, S. Pharyngitis Management: Defining the Controversy. J Gen Intern Med. 2007; 22: 127-30.

Choby, Beth. Diagnosis and Treatment of Streptococcal Pharyngitis. Am Family Physician. 2009; 79: 383-90.

Cirilli, A. Emergency Evaluation and Management of the Sore Throat. Emerg Med Clin North Am.2013: 501-15.

Shulman, S, et al. Clinical Practice Guideline for the Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by the IDSA. 2012.

McIsaac WJ et al. Empirical validation of guidelines for the management of pharyngitis in children and adults. JAMA 2004; 291: 1587-95.

Snow V, et al. Principles of appropriate antibiotic use for acute pharyngitis in adults. Ann Intern Med. 2001; 134:506-8.

Vincent MT, Celestin N., Hussain AN. Pharyngitis. Am Fam Physician 2004; 69:1465-70.