II. Epidemiology

  1. Peak season: Late fall through early spring
    1. Bimodal peaks in November to December and April to May
  2. Prevalence of Streptococcus in peak season
    1. Child <3 years old: Uncommon
    2. Child 3-5 years old: Up to 24% have Group A Beta-hemolytic Streptococcus
    3. Child 5 to 15 years old: Up to 37% have Group A Beta-hemolytic Streptococcus
    4. Adult: Up to 15% with Pharyngitis have Group A Beta-hemolytic Streptococcus
  3. Ages affected
    1. Most commonly affects ages 5 to 12 years old
    2. Not usually seen in children under age 3
  4. Incubation: 24 to 72 hours
  5. Transmission: direct person to person contact
    1. Passed by Saliva and nasal secretions
    2. Increased in crowded settings
    3. May be transmitted with food preparation
    4. Transmission rate from Streptococcus carriers is 3-11%
  6. Infectivity
    1. Decreases 1-3 days after antibiotic started
    2. Return to School and day care recommendations
      1. Antibiotics for minimum of 24 hours
      2. No fever

III. Etiology: Streptococcus Pyogenes

IV. Complications

V. Symptoms

  1. Stretococcal exposure in last 2 weeks (Test Sensitivity 19%, Test Specificity 91%)
  2. Pharyngitis
  3. Fever (Temperature >100.9)
  4. Cough absent
  5. Headache
  6. Myalgia

VII. Differential Diagnosis

  1. See Pharyngitis Causes
  2. Common other causes
    1. Infectious Mononucleosis
      1. Posterior cervical adenopathy, Fatigue and prolonged Pharyngitis
    2. Hand, foot and mouth disease
      1. Oral Lesions, hand and foot skin lesions

VIII. Labs

  1. Streptococcal Rapid Antigen Test
    1. Used to distinguish intermediate probability of Streptococcal Pharyngitis (Centor Score 2-3)
    2. Test Sensitivity: 86%
    3. Test Specificity: 96%
  2. Throat Culture
    1. Used to confirm a negative rapid antigen test
      1. IDSA recommends confirmatory Throat Culture in children (higher risk of Strep Throat complications)
    2. Some authors argue that Throat Culture is unnecessary
      1. They argue rapid antigen test is adequately sensative for a very low risk of Rheumatic Fever
      2. Preventing each case of Rheumatic Fever costs $8 Million in U.S.
      3. Lean (2014) Pediatrics 134(4):771-81 [PubMed]
  3. Antistreptolysin O titer (ASO Titer)
    1. Confirms diagnosis (with serial values), but not helpful in acute disease

IX. Diagnosis

X. Management: Acute Episode

  1. Sore Throat symptomatic management
  2. Prescribe medications in liquid form if odynophagia
  3. Antibiotic Course
    1. Penicillin use requires 10 day course
    2. Five days of alternative antibiotics effective
      1. Amoxicillin Clavulanate (Augmentin)
      2. Ceftibuten
      3. Cefuroxime
      4. Loracarbef
      5. Clarithromycin
      6. Erythromycin estolate
    3. References
      1. Adam (2000) Clin Infect Dis 182:509-16 [PubMed]
  4. First Line Antibiotics
    1. Standard Penicillin Regimen
      1. Penicillin VK (250 mg/5cc; tablets: 250 mg, 500 mg)
        1. Dosing: 12.5 mg/kg (25 mg/kg if severe) up to 500 mg bid for 10 days
        2. Child <9 kg: 125 mg (0.5 tsp) po bid
        3. Child 10-18 kg: 250 (1 tsp) mg po bid
        4. Child 19-27 kg: 375 (1.5 tsp) mg po bid
        5. Adult and child >27 kg: 500 mg orally twice daily for 10 days
      2. Amoxicillin (250 mg/5cc)
        1. Penicillin is preferred first line
        2. Dosing: 25 mg/kg up to 500 mg (up to 875 mg in severe cases) bid for 10 days
        3. Child <9 kg: 125 mg (0.5 tsp) po bid
        4. Child 10-18 kg: 250 (1 tsp) mg po bid
        5. Child 19-27 kg: 375 (1.5 tsp) mg po bid
        6. Adult and child >27 kg: 500 mg bid for 10 day
    2. Macrolide for Penicillin Allergic (2-8% resistance)
      1. Erythromycin Base
        1. Adult: 500 mg PO q6 hours for 10 days
      2. Erythromycin Estolate
        1. Children: 20-40 mg/kg divided every 12 hours
      3. Erythromycin Ethyl Succinate (EES)
        1. Children: 40 mg/kg divided bid (up to 1 g/day)
        2. Adult or child >40 kg: 250 mg qid or 333 mg tid
      4. Azithromycin (200 mg/tsp; 250 mg tablet)
        1. Child 12 mg/kg/day up to 500 mg for 5 days
        2. Adult or child >40 kg: 500 mg daily for 5 days (or 500 mg day 1, then 250 mg qd for 4 days)
      5. Clarithromycin
        1. Adults: 250-500 mg PO bid for 10 days
        2. Children: 15 mg/kg/day divided bid
    3. Clindamycin for Penicillin hypersensitivity
      1. Child: 21 mg/kg/day orally divided every 8 hours (up to 300 mg/dose) for 10 days
      2. Adult: 300 mg orally every 8 hours for 10 days
    4. Single IM dose regimen (Consider for non-compliant)
      1. Benzathine Penicillin (Bicillin LA)
        1. Adults (over 27 kg) 1.2 MU IM
        2. Pediatric (under 27kg): 300,000 - 600,000 U IM

XI. Management: Recurrent Streptococcal Pharyngitis

  1. General
    1. Cephalosporins have higher rates of clinical cure
    2. Casey (2004) Pediatrics 113:866-82 [PubMed]
  2. Cephalexin (Keflex)
    1. Adult: 500 mg PO bid
    2. Child: 25-50 mg/kg/day (up to 1000 mg/day) divided bid
  3. Cefuroxime (Zinacef, Ceftin)
    1. Adult: 250-500 mg PO bid
    2. Child: 20-30mg/kg/day PO divided bid
  4. Cefpodoxime (Vantin)
    1. Adult: 100-400mg PO bid
    2. Child: 10 mg/kg/day divided bid
  5. Cefadroxil (Duricef)
    1. Adult: 1 gram PO qd
    2. Child: 30 mg/kg/day divided bid
  6. Loracarbef (Lorabid)
    1. Adult: 200-400mg PO bid
    2. Child: 15 mg/kg/day divided bid
  7. Amoxicillin Clavulanate (Augmentin)
    1. Adult: 500-875 mg PO bid
    2. Child: 40 mg/kg/day divided bid
  8. Bicillin
    1. Single IM shot (dosing as above)

XII. Management: Tonsillectomy

XIII. Efficacy: Benefits of Antibiotic Treatment

  1. Benefits are at the expense of 10 million antibiotic prescriptions annually for Strep Throat
    1. Risk of serious Allergic Reaction and Diarrheal illness including Clostridium difficile
  2. Prevents Rheumatic Fever
    1. Antibiotics decrease Rheumatic FeverIncidence by 90%
      1. Effective if given in first 9 days of infection
    2. Number Needed to Treat: 3000-4000 patients treated to prevent one case Rheumatic Fever
      1. Data is based on 1940s data, and some estimates estimate NNT at over 1 Million
      2. One third of those Rheumatic Fever patients develop cardiac complications (NNT 12000)
      3. No case reports in U.S. of Rheumatic Fever since 1961
  3. Prevents suppurative complications
    1. Peritonsillar Abscess (variable evidence, NNT 50 to 225)
    2. Acute Sinusitis
    3. Suppurative Otitis Media (NNT 1 in 200)
    4. Cervical Lymphadenitis
  4. Decreases epidemic spread
  5. Decreases duration of disease by about 1 day
  6. Does NOT prevent Post-Streptococcal Glomerulonephritis (PSGN)
  7. References
    1. Del Mar (2006) Cochrane Database Syst Rev (4): CD000023 [PubMed]

XIV. Complications

XV. Complications: Etiologies for recurrent Streptococcal Pharyngitis

  1. Poor Compliance with oral medications (most common)
    1. Day 3: 50% stopped antibiotics
    2. Day 6: 70% stopped antibiotics
    3. Day 9: 80% stopped antibiotics
    4. Families reporting taking all the medication: 80%
  2. Repeat exposure in crowded conditions
    1. School
    2. Daycare
    3. Home or workplace
  3. Eradicated protective throat flora by prior antibiotic
    1. a-hemolytic Streptococcus is protective normal flora
    2. Cephalosporins apparently do less harm
  4. Selected beta-lactam resistance by prior antibiotic
    1. Consider Augmentin for 10 day course
  5. Suppressed Immune response from prior antibiotics
  6. Antibiotic Resistance
    1. Penicillin resistance is infrequent in Strep Throat
    2. Macrolide (Erythromycin, Biaxin, Zithromax)
      1. Resistance 2-8% in U.S.
  7. Chronic Pharyngeal Carriage of Streptococcus pyogenes
    1. Pharyngitis due to another cause

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Ontology: Streptococcal sore throat (C0036689)

Concepts Disease or Syndrome (T047)
ICD9 034.0
ICD10 J02.0
SnomedCT 154302004, 186358002, 186360000, 186361001, 43878008
English Streptococcal sore throat NOS, streptococcal sore throat, streptococcal sore throat (diagnosis), Pharyngitis streptococcal, Strep sore throat, Septic pharyngitis, strep throats, strept throat, streptococcal angina, streptococcus pharyngitis, Pharyngitis;streptococcal, Sore throat;streptococcal, septic sore throat, strep throat, Strep Throat, Streptococcal angina (disorder), Streptococcal sore throat NOS (disorder), Streptococcal pharyngitis (disorder), Streptococcal sore throat, Streptococcal pharyngitis, Septic sore throat, Streptococcal angina, Strep throat, Strept throat, Streptococcal sore throat (disorder), pharyngitis; septic, pharyngitis; streptoccocal, septic; pharyngitis, septic; sore throat, sore throat; septic, sore throat; streptoccocal, streptoccocal; pharyngitis, streptoccocal; sore throat, Septic sore throat due to streptococcal infection, streptococcal pharyngitis
Spanish faringitis estreptocócica, faringitis estreptocócica (trastorno), Infección estreptocócica de garganta, dolor de garganta séptico, dolor de garganta estreptocócico, dolor de garganta estreptocócico (trastorno), angina estreptocócica, SAI (trastorno), angina estreptocócica, SAI, dolor de garganta por estreptococo, SAI, angina estreptocócica, Faringitis estreptocócica
Italian Faringite streptococcica, Angina streptococcica
Dutch streptokokkenangina, Streptokokken-angina, faryngitis; septisch, faryngitis; streptokokken, keelpijn; septisch, keelpijn; streptokokken, septisch; faryngitis, septisch; keelpijn, streptokokken; faryngitis, streptokokken; keelpijn, Streptokokkenfaryngitis, streptokokkenfaryngitis
French Angine streptococcique, Pharyngite streptococcique
German Halsschmerzen durch Streptokokken, Streptokokken-Pharyngitis, Pharyngitis durch Streptokokken
Japanese レンサ球菌性咽頭炎, レンサ球菌性咽喉痛, レンサキュウキンセイインコウツウ, レンサキュウキンセイイントウエン
Czech Streptokoková faryngitida, Streptokoková angína
Korean 사슬알균성 인두염
Hungarian streptococcus pharyngitis, streptococcus torokgyulladás, streptococcalis pharyngitis
Portuguese Faringite estreptocócica