Streptococcal pharyngitis
Streptococcal pharyngitis | |
---|---|
Other names | Streptococcal sore throat, strep throat |
Frequency | 5 to 40% of sore throats[8][9] |
Streptococcal pharyngitis, also known as streptococcal sore throat (strep throat), is pharyngitis (an infection of the pharynx, the back of the throat) caused by Streptococcus pyogenes, a gram-positive, group A streptococcus.[10][11] Common symptoms include fever, sore throat, red tonsils, and enlarged lymph nodes in the front of the neck. A headache and nausea or vomiting may also occur.[12] 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][12]
Strep throat is spread by
Prevention is with airborne precautions,[6] frequent hand washing, and not sharing eating utensils.[12] There is no vaccine for the disease.[1] Treatment with antibiotics is only recommended in those with a confirmed diagnosis.[13] Those infected should stay away from other people until fever is gone and for at least 12 hours after starting treatment. [1] Pain can be treated with paracetamol (acetaminophen) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.[7]
Strep throat is a common bacterial infection in children.[2] It is the cause of 15–40% of sore throats among children[8][14] and 5–15% among adults.[9] Cases are more common in late winter and early spring.[14] Potential complications include rheumatic fever and peritonsillar abscess.[1][2]
Signs and symptoms
The typical signs and symptoms of streptococcal pharyngitis are a
Other symptoms include:
Symptoms typically begin one to three days after exposure and last seven to ten days.[3][14]
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.[9]
-
Mouth wide open showing the throat
A throat infection which on culture tested positive for group A streptococcus. Note the large tonsils with white exudate. -
Mouth wide open showing the throat
Note thepetechiae, or small red spots, on the soft palate. This is an uncommon but highly specific finding in streptococcal pharyngitis.[14] -
A set of large tonsils in the back of the throat, covered in white exudate.
This is a culture-positive case of streptococcal pharyngitis with typical tonsillar exudate in an 8-year-old.
Cause
Strep throat is caused by
Diagnosis
Points | Probability of Strep | Management |
---|---|---|
1 or fewer | <10% | No antibiotic or culture needed |
2 | 11–17% | Antibiotic based on culture or RADT |
3 | 28–35% | |
4 or 5 | 52% | Empiric antibiotics
|
A number of scoring systems exist to help with diagnosis; however, their use is controversial due to insufficient accuracy.[21] The modified Centor criteria are a set of five criteria; the total score indicates the probability of a streptococcal infection.[14]
One point is given for each of the criteria:[14]
- 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.[14]
The
Laboratory testing
A
A positive throat culture or RADT in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt.[24] In adults, a negative RADT is sufficient to rule out the diagnosis. However, in children a throat culture is recommended to confirm the result.[9] 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.[24]
Differential diagnosis
As the symptoms of streptococcal pharyngitis overlap with other conditions, it can be difficult to make the diagnosis clinically.
Prevention
Tonsillectomy may be a reasonable preventive measure in those with frequent throat infections (more than three a year).[26] However, the benefits are small and episodes typically lessen in time regardless of measures taken.[27][28][29] 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.[9] Treating people who have been exposed but who are without symptoms is not recommended.[9] Treating people who are carriers of GAS is not recommended as the risk of spread and complications is low.[9]
Treatment
Untreated streptococcal pharyngitis usually resolves within a few days.[14] Treatment with antibiotics shortens the duration of the acute illness by about 16 hours.[14] The primary reason for treatment with antibiotics is to reduce the risk of complications such as rheumatic fever and retropharyngeal abscesses.[14] Antibiotics prevent acute rheumatic fever if given within 9 days of the onset of symptoms.[17]
Pain medication
Pain medication such as NSAIDs and
Antibiotics
The antibiotic of choice in the United States for streptococcal pharyngitis is penicillin V, due to safety, cost, and effectiveness.[14] Amoxicillin is preferred in Europe.[33] In India, where the risk of rheumatic fever is higher, intramuscular benzathine penicillin G is the first choice for treatment.[17]
Appropriate antibiotics decrease the average 3–5 day duration of symptoms by about one day, and also reduce contagiousness.[24] They are primarily prescribed to reduce rare complications such as rheumatic fever and peritonsillar abscess.[34] The arguments in favor of antibiotic treatment should be balanced by the consideration of possible side effects,[16] 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.[34][35] Antibiotics are prescribed for strep throat at a higher rate than would be expected from how common it is.[36]
Prognosis
The symptoms of strep throat usually improve within three to five days, irrespective of treatment.[24] Treatment with antibiotics reduces the risk of complications and transmission; children may return to school 24 hours after antibiotics are administered.[14] The risk of complications in adults is low.[9] 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.[9]
Complications
Complications arising from streptococcal throat infections include:
The economic cost of the disease in the United States in children is approximately $350 million annually.[9]
Epidemiology
Pharyngitis, the broader category into which Streptococcal pharyngitis falls, is diagnosed in 11 million people annually in the United States.[14] It is the cause of 15–40% of sore throats among children[8][14] and 5–15% in adults.[9] Cases usually occur in late winter and early spring.[14]
References
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- ^ "Pharyngitis (Strep Throat): Information For Clinicians | CDC". www.cdc.gov. 19 December 2022. Retrieved 20 December 2022.
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