Pediatric Pharyngitis Workup
- Author: Harold K Simon, MD, MBA; Chief Editor: Russell W Steele, MD more...
Rapid testing and throat culture
A throat culture remains the standard for diagnosis, though 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 according to 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. Compared with throat culture, such tests are 70-90% sensitive and 95-100% specific.
Rapid screening followed by culture has become the standard in most institutions, especially in developed countries. In repeated investigations, rapid screening with throat culture backup for rapid screen–negative cases has continued to be the most proven strategy. This approach potentially minimizes unnecessary antibiotic administration by helping limit antibiotic use to cases with positive rapid screen findings or those with subsequent positive culture findings.
This approach arises out of the somewhat low sensitivity and specificity of clinical screening. Although the categorization of clinical differentiators developed by the Infectious Diseases Society of America (IDSA) can assist in clinical management (see Presentation), rapid screening followed by culture remains the best combination when resources are available.
The IDSA added that testing for Group A Streptococcus usually is not recommended for the following: patients with sore throat and accompanying symptoms (e.g., cough, rhinorrhea) that strongly suggest a viral etiology; children aged <3 years, because acute rheumatic fever is extremely rare in this age group; and asymptomatic household contacts of patients with Group A Streptococcus pharyngitis.[7, 8]
Testing for viral causes
If Epstein-Barr virus (EBV) is considered, obtain a complete blood count (CBC) to detect atypical cells in the white blood cell (WBC) differential, along with a Monospot test (or another rapid heterophile antibody test). EBV can also produce a subclinical hepatitis with a slightly elevation in aminotransferases.
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 pathogens usually do not call for further diagnostic testing, but viral cultures can be obtained. Viruses can be cultured in special media.
During viral outbreaks (eg, H1N1 influenza), if associated symptoms of the outbreak virus may initially include sore throat, one may opt to screen for streptococcal infection immediately or may elect to screen later, if symptoms persist, in order to rule out Streptococcus as the primary cause of the fever and sore throat.
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.
[Guideline] Michigan Quality Improvement Consortium. Acute pharyngitis in children. Southfield (MI): Michigan Quality Improvement Consortium; 2009 Jan. [Full Text].
Fretzayas A, Moustaki M, Kitsiou S, Nychtari G, Nicolaidou P. The clinical pattern of group C streptococcal pharyngitis in children. J Infect Chemother. 2009 Aug. 15(4):228-32. [Medline].
Centor RM, Atkinson TP, Ratliff AE, Xiao L, Crabb DM, Estrada CA, et al. The clinical presentation of Fusobacterium-positive and streptococcal-positive pharyngitis in a university health clinic: a cross-sectional study. Ann Intern Med. 2015 Feb 17. 162(4):241-7. [Medline].
Barclay L. Sore Throat in Young Adults May Indicate Serious Illness. Medscape Medical News. Available at http://www.medscape.com/viewarticle/839928. Accessed: May 26, 2015.
American Academy of Pediatrics. Report of the committee on infectious diseases. Pickering LK, Baker CJ, McMillan J, Long S (Editors). Red Book. . 27th Edition. Elk Grove Village, Il: American Academy of Pediatrics; 2006:430-439.:
[Guideline] Ayanruoh S, Waseem M, Quee F, Humphrey A, Reynolds T. Impact of rapid streptococcal test on antibiotic use in a pediatric emergency department. Pediatr Emerg Care. 2009 Nov. 25(11):748-50. [Medline].
Shulman ST, Bisno AL, Clegg HW, Gerber MA, Kaplan EL, Lee G, et al. Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clin Infect Dis. 2012 Nov 15. 55 (10):1279-82. [Medline].
Harrist A, Van Houten C, Shulman ST, Van Beneden C, Murphy T. Notes from the Field: Group A Streptococcal Pharyngitis Misdiagnoses at a Rural Urgent-Care Clinic--Wyoming, March 2015. MMWR Morb Mortal Wkly Rep. 2016 Jan 1. 64 (50-51):1383-5. [Medline].
el-Daher NT, Hijazi SS, Rawashdeh NM, al-Khalil IA, Abu-Ektaish FM, Abdel-Latif DI. Immediate vs. delayed treatment of group A beta-hemolytic streptococcal pharyngitis with penicillin V. Pediatr Infect Dis J. 1991 Feb. 10(2):126-30. [Medline].
WANNAMAKER LW, RAMMELKAMP CH Jr, DENNY FW, BRINK WR, HOUSER HB, HAHN EO, et al. Prophylaxis of acute rheumatic fever by treatment of the preceding streptococcal infection with various amounts of depot penicillin. Am J Med. 1951 Jun. 10(6):673-95. [Medline].
Bulloch B, Kabani A, Tenenbein M. Oral dexamethasone for the treatment of pain in children with acute pharyngitis: a randomized, double-blind, placebo-controlled trial. Ann Emerg Med. 2003 May. 41(5):601-8. [Medline].
Krober MS, Weir MR, Themelis NJ, van Hamont JE. Optimal dosing interval for penicillin treatment of streptococcal pharyngitis. Clin Pediatr (Phila). 1990 Nov. 29(11):646-8. [Medline].
Altamimi S, Khalil A, Khalaiwi KA, Milner R, Pusic MV, Al Othman MA. Short versus standard duration antibiotic therapy for acute streptococcal pharyngitis in children. Cochrane Database Syst Rev. 2009 Jan 21. CD004872. [Medline].
Wing A, Villa-Roel C, Yeh B, Eskin B, Buckingham J, Rowe BH. Effectiveness of corticosteroid treatment in acute pharyngitis: a systematic review of the literature. Acad Emerg Med. 2010 May. 17(5):476-83. [Medline].
Schwartz RH, Kim D, Martin M, Pichichero ME. A Reappraisal of the Minimum Duration of Antibiotic Treatment Before Approval of Return to School for Children With Streptococcal Pharyngitis. Pediatr Infect Dis J. 2015 Dec. 34 (12):1302-4. [Medline].
Haelle T. Strep Throat: Treated Kids Can Return to School in 12 Hours. Medscape Medical News. Available at http://www.medscape.com/viewarticle/850338. September 02, 2015; Accessed: April 26, 2016.