Nejm 2001;344:205; 1991;325:783; Ann IM 1989;110:612

Cause:Streptococcus pyogenes, group A, ß-hemolytic, rarely group C or D

Respiratory droplets; occasionally foodborne (Nejm 1969;280:917); 15% of the population carry in pharynx

Sx:Sore throat, fever >100°F, no cough

Si:(Jama 2004;291:1587; 2000;284:2912) Pharyngeal and/or tonsillar exudate (50% sens, 80% specif), anterior cervical tender and/or enlarged nodes (50% sens, 70% specif), T° >10° F (38° C) often (50% sens and specif). Findings 1-4 = Centor score and are crucial (Ann IM 2001;134:506, 509)

10 d without rx

• Acute glomerular nephritis
• Rheumatic fever, in old days 3% in epidemic and 0.5% in endemic type if no rx; now <1/10 000 without rx and <1/100 000 with rx in adults
• Peritonsillar abscess (Quincy abscess) and Lemierre syndrome (Nejm 2004;350:1037) w fusobacterium anaerobic bacteremia including septic pulmonary emboli from jugular phlebitis 5-7 d after acute sore throat

r/o chlamydia (21%) especially TWAR, viral (17%) (rhinovirus, coronavirus, adenovirus, parainfluenza virus, respiratory syncytial virus, echo, coxsackie, acute primary HIV infection), mycoplasma (11%), mononucleosis (EBV) (10%), nongroup A strep (9%), legionella (3%), gonorrhea (1-2%), diphtheria; or Arcanobacterium haemolyticum(a diphtheroid) pharyingitis and scalatiniform rash, esp common in adults, rx w erythromycin

Lab:

Sore throat workup protocol and rx strategies (Jama 2004;291:1587; Ann IM 2001;134:506, 509); rapid strep test all children and adults w Centor scores of 3+ and rx positives; but if rapid test neg, get full throat culture in children

Bact:Rapid office throat swab strep tests take 10 min, cost $2-3; are 90+% specific, but in practice only 60-70% sensitive (30-50% sens, 95% spec—Jama 1992;267:695) so may need to culture negatives esp in children (Med Let 1991;33:40; J Peds 1987;111:80). New optical immunoassay test 80% sens, 95% specif compared to culture, which is 70+% sens and 99% specif (Jama 1997;277:899)

Full throat culture, single swab positive in 75%, 2 swabs in 85%. ß-hemolysis on culture plates. Positive culture may still be just a carrier.

Rx:

Penicillin V or erythromycin 250 mg po tid-qid, × 10 d at least if want rheumatic fever prophylaxis, even bid may be enough (Peds 2000;105:E19), although 20-40% resistance to erythromycin now being reported (Nejm 2002;346:1200; 1992;326:292); or azithromycin. Rx immediately (Ann IM 2001;134:506, 509) if h/o fever, adenopathy, no cough, and exudate; or, if 2-3 of 4 criteria met, get rapid strep and rx only if pos

Tonsillectomy and adenoidectomy does decrease recurrence of strep throats in children with 3 or more documented strep throats/yr over several yr (Nejm 1984;310:674, 717)

of hyperendemic outbreak, eg, marine boot camp (Nejm 1991;325:92), benzathine penicillin 1 million U q 1 mo or po erythromycin to all group members