Streptococcal pharyngitis

The typical signs and symptoms of streptococcal pharyngitis are a sore throat, fever of greater than , tonsillar exudates (pus on the tonsils), and large cervical lymph nodes. 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. File:StrepAug2010.JPG|Mouth wide open showing the throatA throat infection which on culture tested positive for group A streptococcus. Note the large tonsils with white exudate. File:Streptococcal pharyngitis.jpg|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. File:Strep throat2010.JPG|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. Dried bacteria in dust are not infectious, although moist bacteria on toothbrushes or similar items can persist for up to fifteen days. ==Diagnosis==

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. for the diagnosis of streptococcal pharyngitis, with a sensitivity of 90–95%. A positive throat culture or RADT in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt. Other conditions that may present similarly include epiglottitis, Kawasaki disease, acute retroviral syndrome, Lemierre's syndrome, Ludwig's angina, peritonsillar abscess, and retropharyngeal abscess. ==Prevention==

Tonsillectomy may be a reasonable preventive measure in those with frequent throat infections (more than three a year). However, the benefits are small and episodes typically lessen in time regardless of measures taken. 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. Treating people who have been exposed but who are without symptoms is not recommended. Treating people who are carriers of GAS is not recommended as the risk of spread and complications is low. ==Treatment==

Untreated streptococcal pharyngitis usually resolves within a few days. Viscous lidocaine may also be useful. While steroids may help with the pain, they are not routinely recommended. In India, where the risk of rheumatic fever is higher, intramuscular benzathine penicillin G is the first choice for treatment. The arguments in favor of antibiotic treatment should be balanced by the consideration of possible side effects, Antibiotics are prescribed for strep throat at a higher rate than would be expected from how common it is. Erythromycin and other macrolides or clindamycin are recommended for people with severe penicillin allergies. These late-generation antibiotics show a similar effect when prescribed for 3–7 days in comparison to the standard ten days of penicillin when used in areas of low rheumatic heart disease. Streptococcal infections may also lead to acute glomerulonephritis; however, the incidence of this side effect is not reduced by the use of antibiotics. ==Prognosis==

The symptoms of strep throat usually improve within three to five days, irrespective of treatment. Treatment with antibiotics reduces the risk of complications and transmission; children may return to school 24 hours after antibiotics are administered. The risk of complications in adults is low. 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. ==Complications==

Complications arising from streptococcal throat infections include: • Acute rheumatic fever • Glomerulonephritis • Peritonsillar abscess The economic cost of the disease in the United States in children is approximately $350 million annually. ==Epidemiology==

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