Pharyngitis & Strep Throat

A case of strep throat

Clinical features of Group A Beta Hemolytic Strep Pharyngitis

  • Unusual before three years of age and greatest between 5-15
  • Sore throat-usually sudden onset
  • Fever
  • Abdominal pain/vomiting
  • Absence of runny nose, conjunctivitis, diarrhea, and cough
  • More frequent in late winter and spring, uncommon in summer
  • transmitted by oral and nasal secretions 

Physical findings in Streptococcal Pharyngitis

  1. red pharynx with exudate on tonsils and petechiae on soft palate
  2. bilateral tender anterior cervical adenopathy
  3. Scarlet Fever - sandpapery red rash that is primarily on the trunk.  There is circum- oral pallor and a strawberry tongue.  There may be Pasita lines (petechiae) in the antecubital fossa area.   May be accentuated in the underpants area. Can be pruritic and will often peel at the end of the illness. Patients with scarlet fever are not sicker than others without rash.

    Characteristic red cheeks and rash of scarlet fever

    Characteristic strawberry tongue of scarlet fever

  4. Sensitive and specificity not high enough to make the diagnosis without culture confirmation

Differential Diagnosis of “Sore Throat”

  • Group A beta-hemolytic Streptococcus
  • Infectious Mononucleosis (EBV)
  • Other bacterial and viral pharyngitis etiologies (see below)
  • PFAPA (Periodic Fever, Apthous lesions, Pharyngitis, lymphAdenitis)
  • Peritonsillar abcess
  • Retropharyngeal abcess
  • Epiglottitis
  • Lemierre’s Syndrome - Fusibacterium infection, internal jugular vein thrombosis, recent or pharyngeal infection
  • Viral causes of pharyngitis-often will have cough, conjunctivitis, hoarseness and rhinorrhea
  1. Adenovirus
  2. EBV
  3. HSV
  4. Influenza and Parainfluenza
  5. Enteroviruses
  • Other bacterial causes of pharyngitis-benefit of antimicrobial therapy not proven
  1. Chlamydia- benefit of antibioitcs not proven
  2. M. pneumonia- benefit of antibiotics not proven
  3. N. gonorrhea
  4. Group C and G Streptococcus- self limited and not associated with the development of rheumatic fever.

Diagnosis of Streptococcal pharyngitis

  • Because symptoms and physical findings are not reliable to make the diagnosis of strep pharyngitis, throat culture or antigen detection test must be performed,  Throat culture on sheep blood agar and incubate for 24 hours. The throat culture is 90-95% sensitive. Technique is important and must get the posterior pharynx and avoid the uvula and soft palate  The number of colonies on sheep blood agar is not important. A bacitracin disc will differentiate GABS from non Group A. Also may do a rapid strep test which is less sensitive(80-90%) and as specific(95%) as the throat culture. If rapid test is positive treatment may be initiated. If negative, you must plate a throat culture. It is suggested to do two swabs at one time so that if the rapid test is negative, you don't have to swab the throat again. 
  • It is not necessary to culture contacts unless they are symptomatic
  • All suspected streptococcal pharyngitis patients must be cultured or have a + rapid strep test prior to starting antibiotic treatment.
  • It is imperative to only culture appropriate patients to avoid picking up the 10% of the population that are "carriers" of strep. These are patients that have GABHS in heir throats without clinical symptoms and a serologic response. Also, are patients that have persistent positive throat cultures following adequate treatment with antibiotics. The patient is clinically well. These patients are not contagious and are not at increased risk for Acute Rheumatic Fever. 
  • Reculturing after course of treatment is not recommended.


  • Oral penicillin or Amoxicillin for 10 days
  •  LA Bicillin IM 600,000-1,2000.000 Units 1 dose
  • If penicillin allergy. , erythromycin po  There has been an increased of erythromycin resistance with the increased use of macrolides. The incidence decreased with their withdrawal from treatment regimens 
  • Treatment for carrier state if there is a family member with ARF, parental anxiety(strep neurosis), ping pong spread of strep infections, or patient is considering tonsillectomy for recurrent positive cultures. Treatment is oral rifampin during the last 4 days of oral course of penicillin, oral rifampin with LA bicillin, cephalosporins, or oral clindamycin.
  • Patients are not contagious 24 hours after starting therapy and may return to school
  • Returning to school: Patients treated for uncomplicated Strep pharyngitis are not contagious 24 hours after starting therapy and may return to school

Complications of Strep pharyngitis

  • Acute rheumatic fever may be prevented treatment of the strep pharyngitis within 10 days of onset of symptoms. Acute post streptococcal glomerulonephritisis not prevented by therapy
  • Peritonsillar abscesses.
  • Post streptococcal glomerulonephritis-not prevented by treated of GABHS infection
  • PANDAS-(Pediatric Autoimmune Neuropsychiatric Disease Associated with Streptococcus)  Controversial
  • Streptococcal toxic shock.

Prophylaxis and initial treatment for patients with RF :  Pen G 1.2 Million Units IM every 4 weeks.  Duration depends on degree of heart disease:

  • RF with carditis and valvular disease: 10 years of treatment or until 40 years (whichever is longer)
  • RF with carditis but no valvular disease: 10 years or until 21 years of age (whichever is longer)
  • RF without carditis: 5 years or until age 21 (whichever is longer)

Surgical Prophylaxis for patients with RF: only required for patients with carditis and synthetic valve replacement or other prosthetic material.  Treatment should receive a single dose of antibiotics 1 hour prior to surgery.  Treatment should be with a non-penicillin antibiotic such as Clindamycin (20 mg/kg) or Azithromycin (15mg/kg)

Indications for Tonsillectomy and Adenoidectomy

Surgical treatment with tonsillectomy and adenoidectomy are still common for treatment of recurrent throat infections, but clinical trial evidence suggests a limited set of indications for T+A procedures [20].

Tonsillectomy indications - Absolute:

  1. Suspected malignancy
  2. Obstructive sleep apnea (OSA) due to adenotonsillar hypertrophy - with surgery, cure rate for diagnosed OSA is 75%-100%.
  3. Recurrent hemorrhage

Tonsillectomy indications - Relative:

  1. Recurrent tonsillitis - Clinical guidelines vary on the number of infections per year required to meet criteria for tonsillectomy, with a consensus between 3 - 7 tonsillar infections per calendar year.  Regardless of the specific number, the greater the number of infections, the greater the benefit of tonsillectomy.
  2. Recurrent peritonsillar abcess.

Adenoidectomy indications:

  1. OSA due to adenotonsillar hypertrophy
  2. Chronic adenoiditis
  3. Chronic sinusitis
  4. Repeat surgery for recurrent otitis media with effusion (OME)


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