Managing conjunctivitis in general practice

Editor—Neither Everitt et al nor Rietveld et al seem to have consulted an ophthalmologist when designing their studies.¹,² There is little evidence base to back up the clinical features of a condition that many practitioners take for granted. Ophthalmologists, in particular, are aware that adenoviral conjunctivitis tends to follow a distinct clinical pattern: patients often complain of watering and “grittiness” (initially in one eye before involvement of the other), and on closer questioning it often becomes apparent that other family members or work colleagues have had a similar problem. Pre-auricular lymphadenopathy is also a helpful sign. Symptoms may take up to three weeks to resolve, and the patient has not uncommonly been using topical antibiotics for a protracted period at the time of referral—these contain preservatives that may trigger an allergic response in an already inflamed eye, thereby exacerbating the patient's symptoms. A diagnosis of chlamydial conjunctivitis or allergic conjunctivitis is more likely to be made in intractable cases than one of bacterial conjunctivitis. In addition, given the plethora of bacterial commensals in the eye, the temptation to treat a swab result rather than the patient should be resisted.

Incorporating these key features of the patient history and examination into their analyses might have strengthened the results of both studies. Rietveld et al established that if a patient has had sticky eyes on waking then he or she is more likely to have a positive bacterial culture. This does not necessarily translate into a diagnosis of bacterial conjunctivitis. The diagnosis of acute infective conjunctivitis in the study by Everitt et al is too broad. Identifying the exact nature of the pathogen associated with specific symptoms or signs would be valuable in this context, and not particularly difficult to do.^3-5 Often it is possible to identify the cause of conjunctivitis by virtue of a good history and basic examination alone. A move away from widespread empirical use of antibiotics for acute conjunctivitis is to be welcomed, not least because minimising patients' attendance at general practices and eye clinics should help reduce the spread of outbreaks.