streptococcal pharyngitis streptococcal pharyngitis 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. 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. some develop a sandpaper-like rash which is known as scarlet fever. symptoms typically begin one to three days after exposure and last seven to ten days. streptococcal pharyngitisother namesstreptococcal sore throat, strep throata culture positive case of streptococcal pharyngitis with typical tonsillar exudate in a 16-year-old.specialtyinfectious diseasesymptomsfever, sore throat, enlarged lymph nodesusual onset1–3 days after exposureduration7–10 dayscausesgroup a streptococcusrisk factorssharing drinks or eating utensilsdiagnostic methodthroat culture, strep testdifferential diagnosisepiglottitis, infectious mononucleosis, ludwig's angina, peritonsillar abscess, retropharyngeal abscess, viral pharyngitispreventionhandwashing, covering coughstreatmentparacetamol (acetaminophen), nsaids, antibioticsfrequency5 to 40% of sore throats strep throat is spread by respiratory droplets from an infected person, spread by talking, coughing or sneezing, or by touching something that has droplets on it and then touching the mouth, nose, or eyes. it may be spread directly through touching infected sores. it may also be spread by contact with skin infected with group a strep. the diagnosis is made based on the results of a rapid antigen detection test or throat culture. some people may carry the bacteria without symptoms. prevention is by frequent hand washing, and not sharing eating utensils. there is no vaccine for the disease. treatment with antibiotics is only recommended in those with a confirmed diagnosis. those infected should stay away from other people until fever is gone and for at least 12 hours after starting treatment. pain can be treated with paracetamol (acetaminophen) and nonsteroidal anti-inflammatory drugs (nsaids) such as ibuprofen. strep throat is a common bacterial infection in children. it is the cause of 15–40% of sore throats among children and 5–15% among adults. cases are more common in late winter and early spring. potential complications include rheumatic fever and peritonsillar abscess. 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. other symptoms include: headache, nausea and vomiting, abdominal pain, muscle pain, or a scarlatiniform rash or palatal petechiae, the latter being an uncommon but highly specific finding. symptoms typically begin one to three days after exposure and last seven to ten days. 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. mouth wide open showing the throata throat infection which on culture tested positive for group a streptococcus. note the large tonsils with white exudate. mouth wide open showing the throatnote the petechiae, or small red spots, on the soft palate. this is an uncommon but highly specific finding in streptococcal pharyngitis. 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 group a β-hemolytic streptococcus (gas or s. pyogenes). humans are the primary natural reservoir for group a streptococcus. other bacteria such as non–group a β-hemolytic streptococci and fusobacterium may also cause pharyngitis. 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. dried bacteria in dust are not infectious, although moist bacteria on toothbrushes or similar items can persist for up to fifteen days. contaminated food can result in outbreaks, but this is rare. of children with no signs or symptoms, 12% carry gas in their pharynx, and, after treatment, approximately 15% of those remain positive, and are true "carriers". diagnosis modified centor score pointsprobability of strepmanagement 1 or fewer<10%no antibiotic or culture needed 211–17%antibiotic based on culture or radt 328–35% 4 or 552%empiric antibiotics a number of scoring systems exist to help with diagnosis; however, their use is controversial due to insufficient accuracy. the modified centor criteria are a set of five criteria; the total score indicates the probability of a streptococcal infection. one point is given for each of the criteria: 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. the infectious disease society of america recommends against routine antibiotic treatment and considers antibiotics only appropriate when given after a positive test. 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. laboratory testing a throat culture is the gold standard for the diagnosis of streptococcal pharyngitis, with a sensitivity of 90–95%. 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. in areas of the world where rheumatic fever is uncommon, a negative rapid strep test is sufficient to rule out the disease. a positive throat culture or radt in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt. in adults, a negative radt is sufficient to rule out the diagnosis. however, in children a throat culture is recommended to confirm the result. 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. differential diagnosis