The annual incidence of sore throat in general practice has been estimated at 100 per 1000 people per year.1 Some doctors prescribe antibiotics for every patient presenting with a sore throat. Others use clinical scoring systems to establish the probability of group A ß haemolytic streptococcal infection. They use the score result together with a knowledge of the prevalence of streptococci in the community to derive a treatment strategy.2 Thus the management of sore throat, although essentially simple, illustrates Osler's dictum that medicine is a science of uncertainty and an art of probability.3

Bacteria can be isolated from 40-50% of patients with sore throat who present to general practitioners, although up to 30% of those with positive cultures may be carriers.4 Group A ß haemolytic streptococci are the most common bacterial pathogens, with Corynebacterium diphtheriae, and group C and group G streptococci much rarer. An increasing number of cases may be due to synergistic infection with Staphylococcus aureus, Moraxella catarrhalis, Haemophilus influenzae, or anaerobic organisms. Recently, evidence has emerged that some cases of non-streptococcal pharyngitis may be associated with mycoplasma and chlamydial infections.4