Treating strep pharyngitis with appropriate antibiotics decreases risk
of acute rheumatic fever, but not that of post-streptococcal glomerulonephritis.
The clinical scoring system used in the University of Michigan Pharyngitis
Guideline (as described by Wald, et al) can help cross a treatment
threshold without needing to use throat swabs.
For each finding, score +1: Absence of cough, rhinorrhea, and
conjunctivitis; Fever, Erythema, swelling, or exudate of tonsils/pharynx;
Age 5-15, tender anterior cervical nodes; season is Nov-May.
Score of 0: +LR: 0.28 -LR: 1.1; if pre-test probability is 40%, post-test
Score of 5-6: +LR: 3.14 -LR: 0.8; if pre-test probability is 40%, post-test
The clinical scoring system by MsIsaac, et al used fewer clinical
findings (5 vs 6) and had positive likelihood ratios farther away from
Findings: Absence of cough, rhinorrhea, fever, swelling/exudate
of tonsils/pharynx, age<15yrs, tender cervical nodes.
Score of 0: +LR: 0.02 -LR: 1.6; if pre-test probability is 40%, post-test
Score of 4-5: +LR: 6.37 -LR: 0.5; if pre-test probability is 40%, post-test
The University of Michigan Pharyngitis Guidelines uses presence of cough,
rhinorrhea or conjuctivitis to exclude strep pharungitis (level of evidence