Clinical Question: What signs and symptoms predict the presence of bacterial infection in adults with conjunctivitis?

Setting: Outpatient (primary care)

Study Design: Cohort (prospective)

Synopsis: To determine which signs and symptoms are associated with the presence or absence of bacterial infection, researchers enrolled 184 consecutive adult patients who presented to general practitioners in the Netherlands with a red eye and either purulent discharge or sticking of the eyelids. Children and adult patients who wore contact lenses were not studied. Clinicians documented the presence of a number of different signs and symptoms, and obtained a conjunctival sample for culture. The prevalence of bacterial culture was 32 percent.

After individual signs and symptoms were analyzed, the authors determined that eyes glued shut in the morning predicted a bacterial cause, whereas previous episodes of conjunctivitis or a history of itching eyes predicted a nonbacterial cause. Bilateral glued eyes was the highest predictor of bacterial infection (odds ratio = 15; 95 percent confidence interval, 4.4 to 51.5), and 77 percent of patients with this indicator and without the other two indicators had bacterial conjunctivitis. At the other extreme, a bacterial cause was responsible in only 4 percent of patients with itching eyes and a history of conjunctivitis without glued eyes.

Bottom Line: Eyes glued shut in the morning predicts the presence of bacterial infection, whereas a complaint of itching or a history of conjunctivitis indicates a nonbacterial cause. These results do not apply to children with conjunctivitis or to patients who wear contact lenses. (Level of Evidence: 1b)