Streptococcal pharyngitis, or strep throat, is an acute infection and inflammation of the pharynx that affects both children and adults. The most common bacterial etiology of pharyngitis is group A beta-hemolytic Streptococcus (GABHS, or Streptococcus pyogenes). The infection is transmitted via respiratory secretions.
Responsible for 5% to 20% of cases of pharyngitis in adults.
Responsible for 15% to 30% of cases of pharyngitis in children.
Most commonly occurs in children between 5 and 15 years of age.
Symptoms(Often Abrupt Onset): Typical
Pain or difficulty swallowing
Headache – Frequently frontal in location
Younger children – Abdominal pain, nausea, and vomiting
Severe unilateral throat pain should raise concern for a peritonsillar or retropharyngeal abscess, especially if this symptom arises or progresses several days after onset of symptoms. Inability to swallow, or odynophagia, should raise concern for a peritonsillar or retropharyngeal abscess.
Exudate (gray-white), tonsillar pillars or posterior pharynx; occasional palatine petechiae, erythema and edema of the uvula
Anterior cervical lymphadenopathy (classic angle of jaw)
Scarlet fever – Usually face sparing, punctate, erythematous, blanchable, sandpaper-like exanthem that may be accentuated in skin folds and creases (Pastia's lines) and may desquamate during convalescence; bright red tongue with inflamed papillae (strawberry tongue); erythematous pharynx and tonsils covered with exudate.
Children less than 3 years of age – Coryza, purulent nasal discharge, excoriated nares (streptococcosis), and generalized adenopathy.
Exposure to a person with known streptococcal pharyngitis.
History of acute rheumatic fever or rheumatic heart disease.
The incubation period is 24-72 hours.
In most people, fever resolves within 3-5 days, and throat pain resolves within 1 week, even without specific treatment.
Patients with untreated GABHS pharyngitis are infectious during the acute phase and for 1 week after.
Late winter and early spring are peak GABHS seasons.
Complications of GABHS Illness: Suppurative
Perianal dermatitis in children
Peritonsillar/retropharyngeal abscess (quinsy) – Patient has toxic appearance, "hot potato voice," fluctuant peritonsillar mass, and asymmetric deviation of the uvula.
Post-streptococcal glomerulonephritis – Hematuria and edema with history of a recent streptococcal infection (elevated anti-streptolysin O titer).
Acute rheumatic fever – Major (carditis, polyarthritis, chorea, erythema marginatum, subcutaneous nodules) and minor (arthralgias, fever, elevated acute-phase reactants, prolonged PR interval).
Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection.
Post-streptococcal autoimmune dystonia secondary to striatal necrosis.
Post-streptococcal reactive arthritis.
Sydenham's chorea and other autoimmune movement disorders.
ICD10CM: J02.0 – Streptococcal pharyngitis
SNOMEDCT: 43878008 – Streptococcal sore throat
Differential Diagnosis & Pitfalls
Common pitfalls may include missing the diagnosis because of the variability of symptoms and signs and the range of the illness's severity.
When assessing a patient for sore throat, the differential diagnosis should include the following:
Gonococcal pharyngitis (see gonorrhea, primary infection) – Occurs in sexually active individuals; presents with fever, severe sore throat, dysuria, and a characteristic greenish exudate.
Diphtheria – Characterized by moderately sore throat, low-grade fever, and an adherent grayish membrane with surrounding inflammation of the tonsils, pharynx, and nasal passages; presumptive diagnosis if serosanguineous nasal discharge and a grayish-white pharyngeal membrane that is exudative and extends to the uvula and soft palate in association with pharyngitis, tonsillitis, and cervical lymphadenopathy.
Viral pharyngitis – Most common cause of sore throat; suggested by coryza, conjunctivitis, malaise or fatigue, hoarseness, and low-grade fever; atypical symptoms and signs are mouth breathing, vomiting, abdominal pain, and diarrhea.
Infectious mononucleosis – Epstein-Barr virus; cytomegalovirus, most common in patients 15-30 years of age; less likely if posterior cervical lymphadenopathy is absent; associated with hepatosplenomegaly. If amoxicillin or ampicillin is given, 90% of these patients will develop a classic maculopapular rash.
Kawasaki disease – Most often affects children younger than 5 years; characterized by sore throat, fever, bilateral non-purulent conjunctivitis, anterior cervical node enlargement, erythematous oral mucosa, and an inflamed pharynx with a strawberry tongue; and rash.