Treatment of conjunctivitis

Visscher et al subtitle their excellent paper “Breaking the cycle of antibiotic prescribing.”1 They nevertheless acknowledge that physicians’ behaviour is only minimally altered by guidelines and cite several influential external factors affecting antibiotic prescribing, such as parental expectations, school board policies, and lack of patient education materials. I fear that they are too kind. Repeated studies have documented antibiotics being prescribed to patients diagnosed with common colds in the range of 40% to 50% of cases.2–4 This behaviour is not the result of lack of education or inappropriate expectations; both the physician and patient know perfectly well that antibiotics are futile. Given that this behaviour is neither rational nor apparently modifiable, I would suggest that a more useful approach is to adopt a “harm reduction” strategy.

The main problems with the inappropriate prescription of topical antibiotics, as noted by Visscher et al, are the development of resistant organisms, possible adverse reactions, and excessive costs. The first can be avoided by using antibiotics that are not used in other settings; the second can be surmounted by judicious selection of antibiotics with a very low rate of sensitization. All 3 criteria can be met by the use of over-the-counter preparations, such as polymyxin-bacitracin (eg, Polysporin). (Neomycin-containing preparations, such as Neosporin, are less desirable, as the neomycin component is quite sensitizing.) Several years ago, when I worked in a hospital that served as the regional eye-care referral centre, I undertook a study (which I never reported) of the culture results obtained over a 3-month period from all eye swabs, from both the emergency department and the ophthalmology clinic. With the notable exception of the genus Pseudomonas (which is readily identifiable clinically by the characteristic bright green pus), all organisms cultured were uniformly sensitive to polymyxin-bacitracin. I would suggest that weaning physicians off prescription antibiotic preparations by reassuring them that they can effectively kill any bacteria they might encounter with simple over-the-counter preparations—even if this goal is inappropriate—is likely to be more successful than trying to modify their imperative to prescribe.

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