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Strep throat

Strep throat (streptococcal pharyngitis) is the most common infection caused by streptococcus pyogenes.

Signs and Symptoms

The signs and symptoms of strep throat are red, sore throat with white patches on tonsils, swollen lymph nodes in neck, fever, and headache. Nausea, vomiting, and abdominal pain more common in children.

Transmission

The illness is caused by the bacterium Streptococcus pyogenes and is spread by direct, close contact with patients via respiratory droplets (coughing or sneezing). Casual contact rarely results in transmission. Rarely, contaminated food, especially milk and milk products, can result in outbreaks. Untreated patients are most infectious for 2-3 weeks after onset of infection. Incubation period, the period after exposure and before symptoms show up, is 2-4 days. Patient is no longer infectious within 24 h after treatment begins.

Diagnosis

Throat is swabbed for culture or for a rapid strep test (10 to 20 min) which can be done in the doctor's office. If the rapid test is negative, a follow-up culture (which takes 24 to 48 h) may be performed. A negative culture suggests a viral infection, in which case antibiotic treatment should be withheld or discontinued.

Treatment

Antibiotic treatment will reduce symptoms, minimize spread (transmission), and reduce the likelihood of complications. Treatment consists of penicillin (oral drug for 10 days; or single intramuscular injection of penicillin G). Erythromycin is recommended for penicillin-allergic patients. Second-line antibiotics include amoxicillin, clindamycin, and oral cephalosporins. Although symptoms subside within 4 days even without treatment, it is very important to complete the full course of antibiotics to prevent complications.

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