History
Clinical differentiation of the various pathogens of pharyngitis on the basis of history or physical examination is difficult. As Feinstein et al noted in 1962, “[t]he only typical feature of streptococcal infections is the failure to show a single, consistent, typical feature.”
A history of exposure to known carriers, fever, headache, and abdominal pain in conjunction with sore throat suggests group A beta-hemolytic streptococcal (GABHS) pharyngitis. Involvement of other mucous membranes (eg, conjunctivitis, coryza) suggests a viral etiology. Age may also dictate the level of concern because GABHS is rarely a true rheumatogenic pathogen in children younger than 2 years.
Because supportive care is a primary goal in all cases, historical information regarding oral intake and hydration status is important. Obtain information about previous treatments, treatment failures, and medication allergies.
Physical Examination
Although no single finding or combination of physical findings distinguishes GABHS from a viral etiology, several findings are suggestive, including the following:
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Enlarged tonsils
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Pharyngeal erythema
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Tonsillar exudates with necrotic crypts
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Soft-palate petechiae
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Tender cervical adenopathy
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Scarlet fever rash (punctate erythematous macules and fine papules with reddened flexor creases and circumoral pallor), the so-called sandpaper rash
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Conjunctivitis (more common with adenovirus infections)
GABHS pharyngitis is often associated with headache, pharyngeal exudate (see the image below), painful cervical adenopathy, gastrointestinal (GI) symptoms, chills, and high fever. [7]
Posterior pharynx with petechiae and exudates in a 12-year-old girl. Both the rapid antigen detection test and throat culture were positive for group A beta-hemolytic streptococci.
Viral pharyngitis is usually associated with sneezing, rhinorrhea, and cough. For example, H1N1 influenza can present with sore throat but may also have other associated symptoms (eg, rhinorrhea and cough). Mononucleosis is typically exudative with extensive false membranes. Herpangina (usually coxsackievirus A) is associated with papulovesicular lesions of the skin (ie, hand-foot-and-mouth disease). Diphtheria (rare in developed countries) is associated with a thick gray membrane that is difficult to remove, is highly friable, and bleeds if manipulated.
It is important to look for tonsillar asymmetry, which may be a sign of peritonsillar abscesses. This condition can occur in conjunction with soft palate bulging and deviation of the uvula. Pay particular attention to signs of dehydration because supportive care is a primary concern and essential regardless of the etiologic agent.
Although no single or combination of physical findings is specific for distinguishing GABHS from viral etiologies, the Infectious Diseases Society of America (IDSA) has attempted to categorize some of the clinical differentiators. This clinical decision tool was tested in an emerging health care system and was found to be somewhat helpful in reducing unnecessary antibiotic use in resource-limited settings. Rates of disease outbreaks and availability of laboratory and clinical screening tools can help guide management. The IDSA categorization is as follows:
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Category 1 (probable viral pharyngitis) - Conjunctivitis, coryza, cough, diarrhea, viral-like exanthems
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Category 2 (suggestive of possible bacterial pharyngitis) - Fever of more than 38.5°C, tender cervical nodes, headache, petechia of the palate, abdominal pains, or sudden onset (< 12 h).
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Posterior pharynx with petechiae and exudates in a 12-year-old girl. Both the rapid antigen detection test and throat culture were positive for group A beta-hemolytic streptococci.
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Streptococcal pharyngitis. Note the redness and edema of the oropharynx and petechiae, or small red spots, on the soft palate caused by strep throat. Strep throat is caused by group A streptococcus bacteria. These bacteria are spread through direct contact with mucus from the nose or throat of persons who are infected or through contact with infected wounds or sores on the skin.
