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Antibiotics for conjunctivitis decrease symptom duration

In adults or children with acute infective conjunctivitis, are antibiotics effective in decreasing the length and severity of symptoms?

In adults or children with acute infective conjunctivitis, are antibiotics effective in decreasing the length and severity of symptoms?


The investigators enrolled 307 adults and children seen in 30 practices in England who presented with uncomplicated acute infective conjunctivitis.

The patients were randomly assigned, using concealed allocation, to receive immediate antibiotic treatment with chloramphenicol eye drops, delayed antibiotic treatment, or no treatment.

The delayed antibiotic treatment was a prescription for chloramphenicol that could be picked up if symptoms were not better after three days, which occurred 53 per cent of the time.

The main outcomes of this study were the duration of moderately bad symptoms, average severity score for the three days following diagnosis, and belief in the effectiveness of antibiotics.

The duration of moderate symptoms was shorter for both the immediate antibiotic group and the delayed antibiotic group: 3.3 days and 3.9 days, respectively, versus 4.8 days. The average severity of symptoms on days one to three did not differ among the groups.

About half the patients were cultured for the presence of bacteria, and significant bacterial growth was found in 50 per cent. However, the duration and severity of symptoms was not different in patients with bacterial infection and those without.

Nine per cent of patients returned within two weeks; significantly fewer patients in the delayed antibiotic group returned within two weeks.

Patients receiving immediate antibiotic treatment were more likely than patients not receiving treatment to believe antibiotics were effective (number needed to treat = 5).

This belief could have lead these patients to underestimate their symptoms, which might have been responsible for the shorter duration. A better way to control for this belief would be to use placebo eye drops instead of no eye drops.

Level of evidence

1b (see loe.cfm)


Everitt et al. A randomised controlled trial of management strategies for acute conjunctivitis in general practice. BMJ 2006;333:321-6

Bottom line: Treatment with an antibiotic, either immediately or after three days without symptom improvement, shortened the duration of acute conjunctivitis but did not decrease the severity of symptoms.

Delaying the antibiotic reduced the need for antibiotics by almost 50 per cent with similar symptom control and no more repeat visits than immediate antibiotic use.

These results were the same for conjunctivitis with and without an identified bacterial cause.

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