Use of antibiotics for sore throat and incidence of quinsy.

BACKGROUND Quinsy is the most common major suppurative complication of sore throat. Evidence on the effectiveness of antibiotics in preventing quinsy is sparse. AIM To assess the incidence of quinsy and the pattern of presentation, and to identify variables that predict the development of quinsy. DESIGN OF STUDY Case-control study. SETTING UK-wide primary care. METHOD Retrospective analysis of data from the General Practice Research Database (GPRD) for the years 1995-1997. RESULTS There were 606 recorded cases of patients with quinsy, but only 192 (31%) of these patients presented following an initially uncomplicated sore throat. Patients with quinsy were more likely to be aged 21-40 years (odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.7 to 3.6, compared with other ages), smokers (OR = 2.5, 95% CI = 1.8 to 3.5), and male (OR = 1.6, 95% CI = 1.1 to 2.2). Quinsy developed very quickly for most patients (median of 2 days after tonsillitis and 3 days after a sore throat). For cases initially labelled as tonsillitis, there was a nonsignificant trend of antibiotics preventing quinsy (OR = 0.6, 95% CI = 0.3 to 1.3), but no evidence that antibiotics prevent quinsy for cases labelled as sore throat or pharyngitis (OR = 1.2, 95% CI = 0.7 to 2.2). CONCLUSION Most patients with quinsy develop the condition rapidly, and many do not present with a respiratory tract infection to their GP first. The current low doses of antibiotics used in modern community settings may be less likely to protect against quinsy than the trial evidence suggests.