eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease
Pharyngitis: Differential Diagnoses & Workup
Updated: Oct 21, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Diphtheria
Mononucleosis and Epstein-Barr Virus
Infection
Mycoplasma Infections
Other Problems to Be Considered
Coxsackievirus infection
Workup
Laboratory Studies
The following studies are necessary in individuals with suspected pharyngitis:
- Throat culture
- A throat culture remains the criterion standard for diagnosis, although results can take as long as 48 hours.
- Throat culture results are highly sensitive and specific for group A beta-hemolytic streptococci (GABHS), but results can vary based on technique, sampling, and culture media.
- Most institutions and clinics have rapid testing, which is useful when immediate therapy is desired. Rapid testing can be highly reliable when used in conjunction with throat cultures. Several rapid diagnostic tests are available. Such tests are 70-90% sensitive and 95-100% specific compared with throat culture. Rapid screening followed by culture has become the standard in most institutions, especially in developed countries. The somewhat low sensitivity and specificity of clinical screening has led to this approach.
- The Infectious Diseases Society of America (IDSA) has attempted to categorize some of the clinical differentiators. Although this guide can assist in clinical management, rapid screening followed by culture remains the best combination when resources are available. 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:
- Category 1 (probable viral pharyngitis) - Conjunctivitis, coryza, cough, diarrhea, viral-like exanthems
- 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).
- Testing for viral etiologies
- If Epstein-Barr virus (EBV) is considered, obtain a CBC count to detect atypical cells in the WBC differential and a Monospot test (or other rapid heterophile antibody test). EBV can also produce a subclinical hepatitis with a slightly elevated aspartate aminotransferase (SGOT)/alanine aminotransferase (SGPT).
- Monospot findings are often negative in children younger than 6 years with EBV infections and in the first week of symptoms. In adolescents, Monospot testing detects approximately 90% of positive cases ultimately diagnosed with EBV-specific serologies.
- Other viral etiologies usually do not require further diagnostic testing, but viral cultures can be obtained.
- During viral outbreaks (eg, H1N1 influenza), if associated symptoms of the outbreak virus may initially include sore throat, one may opt to screen for Streptococcus infection immediately or may screen later, if symptoms persist, in order to rule out Streptococcus as the primary cause of the fever and sore throat.
Imaging Studies
- Imaging studies are usually not necessary unless a retropharyngeal, parapharyngeal, or peritonsillar abscess is suspected. In such cases, a plain lateral neck film can be used as an initial screening tool.
Procedures
- For patients with peritonsillar abscess, needle aspiration and drainage is warranted. Retropharyngeal abscesses often require surgical drainage.
- For patients with signs of dehydration, administer adequate oral or intravenous fluids. Remember that pain may limit oral intake, complicating hydration maintenance in the patient.
- Parents often ask for referrals for tonsillectomy if their child has had multiple episodes of pharyngitis. Inform parents that tonsillectomy offers only temporary relief. A 50-80% reduction in GABHS pharyngitis is noted during the first 2 years following the procedure; however, by the third year after tonsillectomy, no difference is reported compared with control groups.
More on Pharyngitis |
| Overview: Pharyngitis |
 Differential Diagnoses & Workup: Pharyngitis |
| Treatment & Medication: Pharyngitis |
| Follow-up: Pharyngitis |
| Multimedia: Pharyngitis |
| References |
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References
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Further Reading
Keywords
pharyngitis, sore throat, tonsillitis, tonsillopharyngitis, nasopharyngitis, pharyngeal inflammation, group A beta-hemolytic streptococci, GABHS, GABHS pharyngitis, viral pharyngitis, rheumatic fever, rhinorrhea, laryngitis, adenoviruses, enteroviruses, treatment, diagnosis
