Streptococcal pharyngitis

Streptococcal pharyngitis, also known as strep throat, is an infection of the back of the throat including the tonsils caused by group A streptococcus (GAS).[1] Common symptoms include fever, sore throat, red tonsils, and enlarged lymph nodes in the neck.[1] A headache, and nausea or vomiting may also occur.[1] Some develop a sandpaper-like rash which is known as scarlet fever.[2] Symptoms typically begin one to three days after exposure and last seven to ten days.[2][3]

Streptococcal pharyngitis
Other namesStreptococcal tonsillitis, streptococcal sore throat, strep
A culture positive case of streptococcal pharyngitis with typical tonsillar exudate in a 16-year-old.
SpecialtyInfectious disease
SymptomsFever, sore throat, large lymph nodes[1]
Usual onset1–3 days after exposure[2][3]
Duration7–10 days[2][3]
CausesGroup A streptococcus[1]
Diagnostic methodThroat culture, strep test[1]
Differential diagnosisEpiglottitis, infectious mononucleosis, Ludwig's angina, peritonsillar abscess, retropharyngeal abscess, viral pharyngitis[4]
TreatmentParacetamol (acetaminophen), NSAIDs, antibiotics[1][5]
Frequency5 to 40% of sore throats[6][7]

Strep throat is spread by respiratory droplets from an infected person.[1] It may be spread directly or by touching something that has droplets on it and then touching the mouth, nose, or eyes.[1] Some people may carry the bacteria without symptoms.[1] It may also be spread by skin infected with group A strep.[1] The diagnosis is made based on the results of a rapid antigen detection test or throat culture in those who have symptoms.[8]

Prevention is by washing hands and not sharing eating utensils.[1] There is no vaccine for the disease.[1] Treatment with antibiotics is only recommended in those with a confirmed diagnosis.[8] Those infected should stay away from other people for at least 24 hours after starting treatment.[1] Pain can be treated with paracetamol (acetaminophen) and nonsteroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen.[5]

Strep throat is a common bacterial infection in children.[2] It is the cause of 15–40% of sore throats among children[6][9] and 5–15% among adults.[7] Cases are more common in late winter and early spring.[9] Potential complications include rheumatic fever and peritonsillar abscess.[1][2]

Signs and symptoms

The typical signs and symptoms of streptococcal pharyngitis are a sore throat, fever of greater than 38 °C (100 °F), tonsillar exudates (pus on the tonsils), and large cervical lymph nodes.[9]

Other symptoms include: headache, nausea and vomiting, abdominal pain,[10] muscle pain,[11] or a scarlatiniform rash or palatal petechiae, the latter being an uncommon but highly specific finding.[9]

Symptoms typically begin one to three days after exposure and last seven to ten days.[3][9]

Strep throat is unlikely when any of the symptoms of red eyes, hoarseness, runny nose, or mouth ulcers are present. It is also unlikely when there is no fever.[7]


Strep throat is caused by group A β-hemolytic Streptococcus (GAS or S. pyogenes).[12] Other bacteria such as non–group A β-hemolytic streptococci and fusobacterium may also cause pharyngitis.[9][11] It is spread by direct, close contact with an infected person; thus crowding, as may be found in the military and schools, increases the rate of transmission.[11][13] Dried bacteria in dust are not infectious, although moist bacteria on toothbrushes or similar items can persist for up to fifteen days.[11] Contaminated food can result in outbreaks, but this is rare.[11] Of children with no signs or symptoms, 12% carry GAS in their pharynx,[6] and, after treatment, approximately 15% of those remain positive, and are true "carriers".[14]


Modified Centor score
PointsProbability of StrepManagement
1 or fewer<10%No antibiotic or culture needed
211–17%Antibiotic based on culture or RADT
4 or 552%Empiric antibiotics

A number of scoring systems exist to help with diagnosis; however, their use is controversial due to insufficient accuracy.[15] The modified Centor criteria are a set of five criteria; the total score indicates the probability of a streptococcal infection.[9]

One point is given for each of the criteria:[9]

  • Absence of a cough
  • Swollen and tender cervical lymph nodes
  • Temperature >38.0 °C (100.4 °F)
  • Tonsillar exudate or swelling
  • Age less than 15 (a point is subtracted if age >44)

A score of one may indicate no treatment or culture is needed or it may indicate the need to perform further testing if other high risk factors exist, such as a family member having the disease.[9]

The Infectious Disease Society of America recommends against empirical treatment and considers antibiotics only appropriate when given after a positive test.[7] Testing is not needed in children under three as both group A strep and rheumatic fever are rare, unless a child has a sibling with the disease.[7]

Laboratory testing

A throat culture is the gold standard[16] for the diagnosis of streptococcal pharyngitis, with a sensitivity of 90–95%.[9] A rapid strep test (also called rapid antigen detection testing or RADT) may also be used. While the rapid strep test is quicker, it has a lower sensitivity (70%) and statistically equal specificity (98%) as a throat culture.[9] In areas of the world where rheumatic fever is uncommon, a negative rapid strep test is sufficient to rule out the disease.[17]

A positive throat culture or RADT in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt.[18] In adults, a negative RADT is sufficient to rule out the diagnosis. However, in children a throat culture is recommended to confirm the result.[7] Asymptomatic individuals should not be routinely tested with a throat culture or RADT because a certain percentage of the population persistently "carries" the streptococcal bacteria in their throat without any harmful results.[18]

Differential diagnosis

As the symptoms of streptococcal pharyngitis overlap with other conditions, it can be difficult to make the diagnosis clinically.[9] Coughing, nasal discharge, diarrhea, and red, irritated eyes in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat.[9] The presence of marked lymph node enlargement along with sore throat, fever, and tonsillar enlargement may also occur in infectious mononucleosis.[19] Other conditions that may present similarly include epiglottitis, Kawasaki disease, acute retroviral syndrome, Lemierre's syndrome, Ludwig's angina, peritonsillar abscess, and retropharyngeal abscess.[4]


Tonsillectomy may be a reasonable preventive measure in those with frequent throat infections (more than three a year).[20] However, the benefits are small and episodes typically lessen in time regardless of measures taken.[21][22][23] Recurrent episodes of pharyngitis which test positive for GAS may also represent a person who is a chronic carrier of GAS who is getting recurrent viral infections.[7] Treating people who have been exposed but who are without symptoms is not recommended.[7] Treating people who are carriers of GAS is not recommended as the risk of spread and complications is low.[7]


Untreated streptococcal pharyngitis usually resolves within a few days.[9] Treatment with antibiotics shortens the duration of the acute illness by about 16 hours.[9] The primary reason for treatment with antibiotics is to reduce the risk of complications such as rheumatic fever and retropharyngeal abscesses.[9] Antibiotics prevent acute rheumatic fever if given within 9 days of the onset of symptoms.[12]

Pain medication

Pain medication such as NSAIDs and paracetamol (acetaminophen) helps in the management of pain associated with strep throat.[24] Viscous lidocaine may also be useful.[25] While steroids may help with the pain,[12][26] they are not routinely recommended.[7] Aspirin may be used in adults but is not recommended in children due to the risk of Reye syndrome.[12]


The antibiotic of choice in the United States for streptococcal pharyngitis is penicillin V, due to safety, cost, and effectiveness.[9] Amoxicillin is preferred in Europe.[27] In India, where the risk of rheumatic fever is higher, intramuscular benzathine penicillin G is the first choice for treatment.[12]

Appropriate antibiotics decrease the average 3–5 day duration of symptoms by about one day, and also reduce contagiousness.[18] They are primarily prescribed to reduce rare complications such as rheumatic fever and peritonsillar abscess.[28] The arguments in favor of antibiotic treatment should be balanced by the consideration of possible side effects,[11] and it is reasonable to suggest that no antimicrobial treatment be given to healthy adults who have adverse reactions to medication or those at low risk of complications.[28][29] Antibiotics are prescribed for strep throat at a higher rate than would be expected from how common it is.[30]

Erythromycin and other macrolides or clindamycin are recommended for people with severe penicillin allergies.[9][7] First-generation cephalosporins may be used in those with less severe allergies[9] and some evidence supports cephalosporins as superior to penicillin.[31][32] Streptococcal infections may also lead to acute glomerulonephritis; however, the incidence of this side effect is not reduced by the use of antibiotics.[12]


The symptoms of strep throat usually improve within three to five days, irrespective of treatment.[18] Treatment with antibiotics reduces the risk of complications and transmission; children may return to school 24 hours after antibiotics are administered.[9] The risk of complications in adults is low.[7] In children, acute rheumatic fever is rare in most of the developed world. It is, however, the leading cause of acquired heart disease in India, sub-Saharan Africa and some parts of Australia.[7]

Complications arising from streptococcal throat infections include:

The economic cost of the disease in the United States in children is approximately $350 million annually.[7]


Pharyngitis, the broader category into which Streptococcal pharyngitis falls, is diagnosed in 11 million people annually in the United States.[9] It is the cause of 15–40% of sore throats among children[6][9] and 5–15% in adults.[7] Cases usually occur in late winter and early spring.[9]


  1. "Is It Strep Throat?". CDC. October 19, 2015. Archived from the original on 2 February 2016. Retrieved 2 February 2016.
  2. Török, edited by David A. Warrell, Timothy M. Cox, John D. Firth; with guest ed. Estée (2012). Oxford textbook of medicine infection. Oxford: Oxford University Press. pp. 280–281. ISBN 9780191631733. Archived from the original on 2016-10-10.CS1 maint: extra text: authors list (link)
  3. Jr, [edited by] Allan H. Goroll, Albert G. Mulley (2009). Primary care medicine : office evaluation and management of the adult patient (6th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 1408. ISBN 9780781775137. Archived from the original on 2016-09-15.CS1 maint: extra text: authors list (link)
  4. Gottlieb, M; Long, B; Koyfman, A (May 2018). "Clinical Mimics: An Emergency Medicine-Focused Review of Streptococcal Pharyngitis Mimics". The Journal of Emergency Medicine. 54 (5): 619–629. doi:10.1016/j.jemermed.2018.01.031. PMID 29523424.
  5. Weber, R (March 2014). "Pharyngitis". Primary Care. 41 (1): 91–8. doi:10.1016/j.pop.2013.10.010. PMID 24439883.
  6. Shaikh N, Leonard E, Martin JM (September 2010). "Prevalence of streptococcal pharyngitis and streptococcal carriage in children: a meta-analysis". Pediatrics. 126 (3): e557–64. doi:10.1542/peds.2009-2648. PMID 20696723.
  7. Shulman, ST; Bisno, AL; Clegg, HW; Gerber, MA; Kaplan, EL; Lee, G; Martin, JM; Van Beneden, C (Sep 9, 2012). "Clinical Practice Guideline for the Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by the Infectious Diseases Society of America". Clinical Infectious Diseases. 55 (10): e86–102. doi:10.1093/cid/cis629. PMID 22965026.
  8. Harris, AM; Hicks, LA; Qaseem, A (19 January 2016). "Appropriate Antibiotic Use for Acute Respiratory Tract Infection in Adults: Advice for High-Value Care From the American College of Physicians and the Centers for Disease Control and Prevention". Annals of Internal Medicine. 164 (6): 425–34. doi:10.7326/M15-1840. PMID 26785402.
  9. Choby BA (March 2009). "Diagnosis and treatment of streptococcal pharyngitis". Am Fam Physician. 79 (5): 383–90. PMID 19275067. Archived from the original on 2015-02-08.
  10. Brook I, Dohar JE (December 2006). "Management of group A beta-hemolytic streptococcal pharyngotonsillitis in children". J Fam Pract. 55 (12): S1–11, quiz S12. PMID 17137534.
  11. Hayes CS, Williamson H (April 2001). "Management of Group A beta-hemolytic streptococcal pharyngitis". Am Fam Physician. 63 (8): 1557–64. PMID 11327431. Archived from the original on 2008-05-16.
  12. Baltimore RS (February 2010). "Re-evaluation of antibiotic treatment of streptococcal pharyngitis". Curr. Opin. Pediatr. 22 (1): 77–82. doi:10.1097/MOP.0b013e32833502e7. PMID 19996970.
  13. Lindbaek M, Høiby EA, Lermark G, Steinsholt IM, Hjortdahl P (2004). "Predictors for spread of clinical group A streptococcal tonsillitis within the household". Scand J Prim Health Care. 22 (4): 239–43. doi:10.1080/02813430410006729. PMID 15765640.
  14. Rakel, edited by Robert E. Rakel, David P. (2011). Textbook of family medicine (8th ed.). Philadelphia, PA.: Elsevier Saunders. p. 331. ISBN 9781437711608. Archived from the original on 2017-09-08.CS1 maint: extra text: authors list (link)
  15. Cohen, JF; Cohen, R; Levy, C; Thollot, F; Benani, M; Bidet, P; Chalumeau, M (6 January 2015). "Selective testing strategies for diagnosing group A streptococcal infection in children with pharyngitis: a systematic review and prospective multicentre external validation study". Canadian Medical Association Journal. 187 (1): 23–32. doi:10.1503/cmaj.140772. PMC 4284164. PMID 25487666.
  16. Smith, Ellen Reid; Kahan, Scott; Miller, Redonda G. (2008). In A Page Signs & Symptoms. In a Page Series. Hagerstown, Maryland: Lippincott Williams & Wilkins. p. 312. ISBN 978-0-7817-7043-9.
  17. Lean, WL; Arnup, S; Danchin, M; Steer, AC (October 2014). "Rapid diagnostic tests for group A streptococcal pharyngitis: a meta-analysis". Pediatrics. 134 (4): 771–81. doi:10.1542/peds.2014-1094. PMID 25201792.
  18. Bisno AL, Gerber MA, Gwaltney JM, Kaplan EL, Schwartz RH (July 2002). "Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. Infectious Diseases Society of America" (PDF). Clin. Infect. Dis. 35 (2): 113–25. doi:10.1086/340949. PMID 12087516.
  19. Ebell MH (2004). "Epstein-Barr virus infectious mononucleosis". Am Fam Physician. 70 (7): 1279–87. PMID 15508538. Archived from the original on 2008-07-24.
  20. Johnson BC, Alvi A (March 2003). "Cost-effective workup for tonsillitis. Testing, treatment, and potential complications". Postgrad Med. 113 (3): 115–8, 121. doi:10.3810/pgm.2003.03.1391. PMID 12647478.
  21. van Staaij BK, van den Akker EH, van der Heijden GJ, Schilder AG, Hoes AW (January 2005). "Adenotonsillectomy for upper respiratory infections: evidence based?". Archives of Disease in Childhood. 90 (1): 19–25. doi:10.1136/adc.2003.047530. PMC 1720065. PMID 15613505.
  22. Burton, MJ; Glasziou, PP; Chong, LY; Venekamp, RP (19 November 2014). "Tonsillectomy or adenotonsillectomy versus non-surgical treatment for chronic/recurrent acute tonsillitis" (PDF). The Cochrane Database of Systematic Reviews (11): CD001802. doi:10.1002/14651858.CD001802.pub3. PMID 25407135.
  23. Morad, Anna; Sathe, Nila A.; Francis, David O.; McPheeters, Melissa L.; Chinnadurai, Sivakumar (17 January 2017). "Tonsillectomy Versus Watchful Waiting for Recurrent Throat Infection: A Systematic Review". Pediatrics. 139 (2): e20163490. doi:10.1542/peds.2016-3490. ISSN 0031-4005. PMC 5260157. PMID 28096515. Archived from the original on 13 August 2017.
  24. Thomas M, Del Mar C, Glasziou P (October 2000). "How effective are treatments other than antibiotics for acute sore throat?". Br J Gen Pract. 50 (459): 817–20. PMC 1313826. PMID 11127175.
  25. "Generic Name: Lidocaine Viscous (Xylocaine Viscous) side effects, medical uses, and drug interactions". Archived from the original on 2010-04-08. Retrieved 2010-05-07.
  26. Wing, A; Villa-Roel, C; Yeh, B; Eskin, B; Buckingham, J; Rowe, BH (May 2010). "Effectiveness of corticosteroid treatment in acute pharyngitis: a systematic review of the literature". Academic Emergency Medicine. 17 (5): 476–83. doi:10.1111/j.1553-2712.2010.00723.x. PMID 20536799.
  27. Bonsignori F, Chiappini E, De Martino M (2010). "The infections of the upper respiratory tract in children". Int J Immunopathol Pharmacol. 23 (1 Suppl): 16–9. PMID 20152073.
  28. Snow V, Mottur-Pilson C, Cooper RJ, Hoffman JR (March 2001). "Principles of appropriate antibiotic use for acute pharyngitis in adults". Ann Intern Med. 134 (6): 506–8. doi:10.7326/0003-4819-134-6-200103200-00018. PMID 11255529.
  29. Hildreth, AF; Takhar, S; Clark, MA; Hatten, B (September 2015). "Evidence-Based Evaluation And Management Of Patients With Pharyngitis In The Emergency Department". Emergency Medicine Practice. 17 (9): 1–16, quiz 16–7. PMID 26276908.
  30. Linder JA, Bates DW, Lee GM, Finkelstein JA (November 2005). "Antibiotic treatment of children with sore throat". J Am Med Assoc. 294 (18): 2315–22. doi:10.1001/jama.294.18.2315. PMID 16278359.
  31. Pichichero, M; Casey, J (June 2006). "Comparison of European and U.S. results for cephalosporin versus penicillin treatment of group A streptococcal tonsillopharyngitis". European Journal of Clinical Microbiology & Infectious Diseases. 25 (6): 354–64. doi:10.1007/s10096-006-0154-7. PMID 16767482.
  32. van Driel, ML; De Sutter, AI; Habraken, H; Thorning, S; Christiaens, T (11 September 2016). "Different antibiotic treatments for group A streptococcal pharyngitis". The Cochrane Database of Systematic Reviews. 9: CD004406. doi:10.1002/14651858.CD004406.pub4. PMC 6457741. PMID 27614728.
  33. "UpToDate Inc". Archived from the original on 2008-12-08.
  34. Stevens DL, Tanner MH, Winship J, et al. (July 1989). "Severe group A streptococcal infections associated with a toxic shock-like syndrome and scarlet fever toxin A". N. Engl. J. Med. 321 (1): 1–7. doi:10.1056/NEJM198907063210101. PMID 2659990.
  35. Hahn RG, Knox LM, Forman TA (May 2005). "Evaluation of poststreptococcal illness". Am Fam Physician. 71 (10): 1949–54. PMID 15926411.
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