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Strep throat

Strep throat
Classification & external resources
Strep throat
ICD-10 J02.0
ICD-9 034.0

Strep throat (AE), also Streptococcal pharyngitis or Streptococcal Sore Throat is a form of Group A streptococcal infection that affects the pharynx.



  • Severe sore throat
  • Yellow and white patches in the throat.
  • Difficulty swallowing
  • Tender cervical lymphadenopathy
  • Red and enlarged tonsils
  • Halitosis
  • Fever of 38°C (101F) or greater.
  • Rash [1]
  • Frequent cold chills
  • Absence of cough
  • White spots on tonsils
  • Desquamation (peeling skin on fingertips) a few weeks after treatment


Signs and symptoms

A study of 729 patients with pharyngitis in which 17% had a positive throat culture for group A streptococcus, identified the following four best predictors of streptococcus[2]:

1. Lack of cough

2. Swollen and tender anterior cervical lymph nodes

3. (Marked) tonsillar exudates. Although the original study did not specify the degree of exudate, 'marked exudate' may be more accurate. A subsequent study of 693 patients with 9.7% having positive cultures found that 'marked exudates' had a sensitivity and specificity of 21% and 70% while 'pinpoint exudates' were nonspecific with sensitivity and specificity of 22% and 45%[3].

4. History of fever

When these findings are counted in a patient, the probabilities of positive cultures in the original study (prevalence=17%) are[2]:

  • 4 findings -> 55.7%
  • 3 findings -> 30.1 – 34.1%
  • 2 findings -> 14.1 – 16.6%
  • 1 findings -> 6.0 - 6.9%
  • 0 findings -> 2.5%

5. Throat feels swollen

The probabilities can also be computed with the following equation: X = −2.69 + 1.04 (exudtons) + 1 (swolacn) - 0.95 (cough) + 0.89 (fevhist)


The throat of the patient is swabbed for culture or for a rapid strep test (5 to 15 min) which can be done in the doctor's office. A rapid test tests for the presence of antibodies against the bacteria. If the rapid test is negative, a follow-up culture (which takes 24 to 48 hours) may be performed. A negative culture could suggest a viral infection, in which case antibiotic treatment should be withheld or discontinued. Ask your doctor for further examination it still may be possible that you are suffering from a bacterial infection. It is possible to test too early and testing can be deceiving.


Strep throat is caused by the bacterium streptococcus pyogenes. [4], [5], [6], and [7] It is spread by direct, close contact with an infected person via respiratory droplets. In one study 114 patients, with positive throat cultures and a presence of group A beta-hemolytic streptococci (GAS), were studied to see transmission within their families through pillow cases, toys, and patients tooth brush and of those 114 patients studied 50 patients received hygiene instructions to follow and 64 were not given hygiene instructions. The percent of culture-verified recurrences was 35% [8]. Casual contact can result in transmission like the study that was done on transmission in households by two Norwegian health centers. 127 patients, with positive throat cultures, and their families were studied and 4 weeks after the beginning of the study other members of the household were asked if they had any positive throat culture since the beginning of the study. In 30 households there was one more case of infection, in 22 households 2 more cases, 6 households with 3 cases, and 2 households with 4 cases [9]. Rarely, contaminated food, especially milk and milk products, can result in outbreaks. One study stated that a sandwich layer cake had been served at a party and 2 days later 4 family members that ate the cake fell ill with high temperatures, shivers, and sore throats and the 2 family members that didn’t eat the cake were not infected. The cake was made of 3 layers of bread with filling, which consisted of mayonnaise, caviar, cream, mimosa salad, liver pate, and cucumber, and there was a layer of mayonnaise, ham, meatballs, eggs, and prawns. The cake had been served to at least 16 parties and all individuals who attended parties where the cake was served were questioned and of the 212 who had eaten the cake, 153(72%) fell ill with sore throat, fever, and shivering. [10]

The incubation period for strep throat is thought to be between two to five days. One outbreak’s incubation period was two to eight days. It began in a dormitory when 394 primary and secondary cases had positive throat cultures between May 20th and May 28th. Later it was found the outbreak started from 2 cooks who were positive for GAS also. 268 of a total of 943 students who ate the suspected food from May 18th became GAS positive. [11]

Strep is caused by a bacteria of a type called group A beta-hemolytic streptococci. [12], [13], [14], and [15] Symptoms include sore throat, fever, headache, and in some cases, chills, nausea, and vomiting. Family Physicians took a “strep” score for 621 patients where one point was assigned for each of the following symptoms: temperature greater than 38 C, absence of cough, tender anterior cervical adenopathy, tonsillar swelling or exudate, and age younger than 15 and subtracting a point for age older than 45. A score of one or less was negative with no throat culture or antibiotic, a score of two or three was considered indeterminate with a throat culture and antibiotic based on throat culture, and a score of four or greater was positive with throat culture and antibiotics. The occurrence of strep was 17% score of two, 35% score of three, and 51% score of four or more. [16] The patient usually experiences swelling of the tonsils and lymph nodes in the neck and swelling can also be located in the soft palate in the top of the mouth. Authors identified, reviewed, and pooled data of studies of diagnosing of group A beta-hemolytic streptococcal pharyngitis in patients with a sore throat. The absence of tender anterior cervical lymph nodes, tonsillar enlargement, and tonsillar or pharyngeal exudates was most useful in ruling out strep throat with a negative likelihood of 0.74. [17]


Treatment will reduce symptoms slightly like in one study of 11 adult patients with sore throat and confirmed GAS infection that were evaluated daily after the start of antibiotic treatment to register symptoms and signs and to measure body temperature. The mean reduction rate was great but was the greatest reduction after 2 days out of all symptoms scores was for muscle or joint pain, 86%, and the lowest for sore throat, 67%. [18] Treatment, which consists of penicillin (orally for 10 days or a single intramuscular injection of penicillin G), will also minimize transmission which is why until children that are positive for GAS have taken 24 hours of antibiotic should not go back to school or day care. In one study they assessed the potential risk of transmission to close school contact by taking 47 children with positive throat cultures and randomly selected them to receive penicillin V, penicillin G, or erythromycin. Throat culture were then taken 24 hours after start of antibiotics and 17 (36.2%) had positive throat cultures and 39 (83%) of the patients became culture negative. [19]

Cephalosporins, such as cefazoline, cefuroxime, and ceftriaxone, are recommended for penicillin-allergic patients. In a study 41 patients, with confirmed penicillin allergy, were evaluated with cefazoline, cefuroxime, and ceftriaxone, all cephalosporins, to see the allergic reaction. Skin tests with cephalosporins were clearly negative in 39 patients and all 41 patients tolerated the three cephalosporins administered. [20] Second-line antibiotics include amoxicillin, clindamycin, and oral cephalosporins. 152 patients in a study all with positive throat cultures were randomly assigned to receive either penicillin orally 3 times a day for 10 days or amoxicillin orally once a day for 10 days. At the 18 to 24 hour follow-up 1 of the 73 patients taking penicillin had a positive throat culture and none of 79 patients taking amoxicillin. [21] Throat cultures were performed on elementary schools children in Pittsburgh. Of those students 209 were treated with antibiotic and 5% were treated with clindamycin and there were no clinical treatment failures. [22] It is important to complete the full course of antibiotics to prevent rheumatic fever or an abscess on the tonsils. In one report of 500 patients 30% had group A beta-hemolytic streptococcal pharyngitis 0.2% had rheumatic fever and 0.2% had peritonsillar abscess (an abscess on the tonsils) (Ebell, 2004). Another complication that can occur is acute glomerulonephritis like in one study where 5318 children with positive throat cultures for GAS were randomly given either 10 days of penicillin or 5 days of amoxicillin, clarithromycin, or erythromycin. Out of all the children two got acute glomerulonephritis. [23]

The overall summary odds ratio for the bacteriologic cure rate significantly favors cephalosporins compared with penicillin like in one study that compared penicillin and cephalosporin cure rates of GAS by taking 7125 patients in 35 trials with positive throat cultures and randomly administering cephalosporin or penicillin for a 10-day treatment. The primary outcome odds ratio of cure rate comparing the two was 3.02 significantly favoring cephalosporin treatments. [24] Penicillin causes a distinctive rash if the true illness is viral and not bacterial. In one study 94 patients who were hypersensitive to amoxicillin and penicillin G took them 2 times a day for 2 weeks and used skin test to obtain results. 22 of the 94 patients had a clear skin reaction, 20 with delayed reaction and 2 with immediate reaction. [25] The most common virus illness responsible for strep-like symptoms is glandular fever, also known as mononucleosis. In a study at least 98% of 500 patients with confirmed infectious mononucleosis had sore throat, lymph node enlargement, fever, and tonsillar enlargement. Symptoms that are similar to streptococcal pharyngitis (strep throat) symptoms. [26]

Other ways to relieve strep symptoms include taking nonprescription medications (ibuprofen and acetaminophen/paracetamol) for throat pain and fever reduction. A total of 200 pediatric patients with a mean temperature of 39.2˚C were studied and were randomly given an oral dose of ibuprofen or paracetamol. The reduction in temperature between both treatments didn’t differ, each had a mean decrease difference of 1.2˚C or 1.3˚C. [27] A study in general practice with 8233 patients with musculoskeletal or back pain and sore throat were randomly given 7 days of aspirin, paracetamol, or ibuprofen. The overall pain reduction for musculoskeletal of back pain was 48% and 31% for sore throat. [28]

A 2003 study found extract of Pelargonium sidoides was superior compared to placebo for the treatment of acute non-GABHS tonsillopharyngitis in children. Treatment with EPs 7630 reduced the severity of symptoms and shortened the duration of illness by at least 2 days.[29]

Lack of Treatment

The symptoms of strep throat usually improve even without treatment in five days, but the patient is contagious for several weeks. Lack of treatment or incomplete treatment of strep throat can lead to various complications. Some of them may pose serious health risks.

Infectious complications

  • The active infection may occur in the throat, skin, and in blood.
  • Skin and soft tissues may become infected, resulting in redness, pain, and swelling. Skin and deep tissues may also become necrotic (rare).
  • Scarlet fever is caused by toxins released by the bacteria.
  • Rarely, some strains may cause a severe illness in which blood pressure is reduced and lung injury and kidney failure may occur (toxic shock syndrome).

Noninfective complications

  • During the infection, antibodies (disease–fighting chemicals) are produced, sometimes causing a rare complication that can result after the organism is cleared, when these antibodies cause disease in body organs.
  • Rheumatic fever is a heart disease in which the inflammation of heart muscle and scarring of heart valves can occur.
  • Glomerulonephritis is a kidney disease in which the injury may lead to kidney failure.[30]

See also

  • PANDAS - Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections
  • Tonsillitis
  • Pharyngitis
  • Psoriasis
  • Herpes, as the symptoms of these two ailments are very similar, do not mistake one for the other.


  1. ^ Kids Health
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world book encyclopedia

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Strep_throat". A list of authors is available in Wikipedia.
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