A Girl With a Sore Throat, Fever, and Strawberry Tongue
A 10-year-old girl presented with a 3-day history of fever, sore throat, pain on swallowing, and headache. There was no associated cough, runny nose, or hoarseness. She had been exposed to a child with sore throat a few days ago.
Physical examination findings included a temperature of 38.5°C, an inflamed pharynx, enlarged tonsils, tonsillar exudates, a strawberry tongue (Figure), and enlarged tender anterior cervical lymph nodes. She did not have a skin rash, peeling of skin, conjunctival congestion, oral ulcers, or splenomegaly.
What’s your diagnosis?
(Answer and discussion on next page)
Answer: Group A β-hemolytic streptococcal pharyngitis
The history and physical examination findings were suggestive of group A β-hemolytic streptococcal pharyngitis. The diagnosis was confirmed with a throat culture that grew group A β-hemolytic streptococcus (GABHS).
EPIDEMIOLOGY
GABHS, also known as Streptococcus pyogenes, is the most common bacterial cause of acute pharyngitis in children.1 GABHS pharyngitis occurs mainly in children aged 5 to 15 years.2,3 Although the infection can occur at any age, it is uncommon before 3 years of age and after 45 years of age.4 In temperate climates, the incidence is highest in the winter and early spring.2 It is estimated that GABHS accounts for 20% to 30% of cases of acute pharyngitis in school-aged children.5 Both sexes are affected equally.
The major route of spread is person-to-person via respiratory droplets.1 Crowding facilitates transmission.6 Fomites and household pets are the most common vectors of GABHS infection.6 Asymptomatic carriage is common in young children.6 Patients are most contagious during the acute stage of the illness and usually are not contagious 24 hours after appropriate antibiotic therapy has been started.1,4
CLINICAL MANIFESTATIONS
The incubation period is from 2 to 5 days.6 Children commonly present with a sudden onset of sore throat, pain on swallowing, and fever.1 The pain often is worse on one side.5
Other symptoms, such as headache, nausea, vomiting, and abdominal pain, also may be present, especially in younger children.5 Physical findings include a beefy red pharynx, enlarged and erythematous tonsils, pharyngeal exudates, enlarged tender anterior cervical lymph nodes, and sometimes palatal petechiae, a strawberry tongue, and a scarlatiniform rash. The latter is caused by streptococcal pyrogenic exotoxins and, when present, signifies scarlet fever.6 Typically, the rash blanches on pressure, has the texture of gooseflesh or coarse sandpaper, and is better felt than seen. The rash may be more prominent in flexor skin creases, especially in the antecubital fossae (Pastia lines).
DIFFERENTIAL DIAGNOSIS AND DIAGNOSIS
Clinical diagnosis can be difficult, because with the exception of the rash of scarlet fever, none of the clinical findings described in the preceding section is specific for GABHS pharyngitis. Other bacterial causes of pharyngitis include group C and group G β-hemolytic streptococci, Mycoplasma pneumoniae, Chlamydia pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and anaerobic species.4,7 Viral causes of pharyngitis include adenovirus, rhinovirus, coronavirus, Epstein-Barr virus, influenza virus, and parainfluenza virus.4,7 The presence of cough, rhinorrhea, hoarseness, conjunctivitis, stomatitis, herpangina, viral exanthem, generalized lymphadenopathy, and splenomegaly favors a viral etiology.8
Many clinical scoring systems have been developed to assist in the diagnosis of GABHS pharyngitis.9 The modified Centor score is one in popular use, and it has been validated for use in children and adults with sore throat.9,10 One point is assigned to each of 5 criteria: temperature above 38°C, swollen tender anterior cervical nodes, tonsillar exudates, age between 3 and 14 years, and absence of cough. One point is taken from the score for patients 45 years of age and above.10
Clinical criteria can help a physician select patients who have higher likelihood of GABHS pharyngitis and who need to be tested. If the modified Center score is greater than 2, a microbiologic test should be performed.
The culture of a throat swab specimen on sheep blood agar plate remains the gold standard for documenting the presence of GABHS but requires 18 to 24 hours.11 If performed properly, the sensitivity of a single throat swab culture for detecting GABHS is 90% to 95%.11,12 Throat swab specimens should be obtained by swabbing the surface of both tonsillar surfaces or fossae and the posterior pharyngeal wall.11
A rapid antigen detection test performed in the office adds immediately to the cost of care but can provide results in minutes.13 All rapid antigen detection tests involve acid extraction of the group-specific carbohydrate antigen from the GABHS cell wall and identification of the antigen by an immunologic reaction.13 The specificity of these tests consistently has been greater than 95%.5,12 Thus, a positive test can be considered definitive and obviates the need for culture. The Infectious Diseases Society of America recommends confirming a negative rapid antigen detection test with a throat culture result, unless the physician has ascertained in his or her practice that the sensitivity of the rapid antigen detection test used is comparable with that of a throat culture.11
COMPLICATIONS
Suppurative complications include suppurative cervical lymphadenitis, cellulitis, perianal dermatitis, erysipelas, staphylococcal scalded skin syndrome, peritonsillar abscess, retropharyngeal abscess, otitis media, pneumonia, sinusitis, and mastoiditis.3 GABHS pharyngitis rarely can result in bacteremia, necrotizing fasciitis, and streptococcal toxic shock–like syndrome.3
Nonsuppurative immune-mediated complications include acute rheumatic fever, acute poststreptococcal glomerulonephritis, reactive arthritis-synovitis, and pediatric autoimmune neuropsychiatric disorder.3,14 Henoch-Schönlein purpura and guttate psoriasis may occur following GABHS pharyngitis.
MANAGEMENT
Once GABHS pharyngitis has been diagnosed on the basis of the results of a rapid antigen detection test or throat culture, antimicrobial therapy is indicated to prevent local suppurative complications and the subsequent development of acute rheumatic fever, as well as to shorten the clinical course and minimize the spread of infection to other individuals.5,14
Because of its proven efficacy, safety, and narrow spectrum of antimicrobial activity, penicillin V remains the drug of choice for GABHS, except in patients who are allergic to penicillin.11 Amoxicillin often is preferred over penicillin V because of the better taste of the suspension and its availability as chewable tablets.11,12
In patients who are allergic to penicillin, narrow-spectrum cephalosporins, clindamycin, and macrolides are acceptable alternatives.11 Because of the possibility of cross-reactivity, however, patients with a history of immediate, anaphylactic-type hypersensitivity to penicillin should not be treated with a cephalosporin.12 If warranted, the use of acetaminophen or ibuprofen for the symptomatic relief of moderate to severe pain or control of high fever associated with GABHS pharyngitis may be considered.
PROGNOSIS
The prognosis for adequately treated GABHS pharyngitis is excellent. Suppurative complications are uncommon and respond readily to treatment. The incidence of acute rheumatic fever has declined steadily over the past several decades. Unfortunately, poststreptococcal glomerulonephritis does not seem to be preventable with antibiotic therapy.
Alexander K. C. Leung, MD, is a clinical professor of pediatrics at the University of Calgary and a pediatric consultant at the Alberta Children’s Hospital in Calgary.
Benjamin Barankin, MD, is medical director and founder of the Toronto Dermatology Centre.
Kam-Lun Ellis Hon, MD, is a professor of pediatrics at the Chinese University of Hong Kong.
REFERENCES
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8. Leung AKC, Pinto-Rajas A. Infectious mononucleosis. Consultant. 2000;40:134-136.
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12. Choby BA. Diagnosis and treatment of streptococcal pharyngitis. Am Fam Physician. 2009;79(5):383-390.
13. Leung AKC, Newman R, Kumar A, Davies HD. Rapid antigen detection testing in diagnosing group A β-hemolytic streptococcal pharyngitis. Expert Rev Mol Diagn. 2006;6(5):761-766.
14. Barash J. Group A streptococcal throat infection—to treat or not to treat? Acta Paediatr. 2009;98(3):434-436.