Written by Vivian Lei
The presence of certain clinical findings can help clinicians gauge the likelihood of bacterial versus viral conjunctivitis, although data are limited.
Why does this matter?
Differentiating bacterial and viral conjunctivitis based on clinical evaluation can be difficult, leading many clinicians to prescribe topical antibiotics for cases of infectious conjunctivitis that are likely viral. Overprescribing antibiotics can promote bacterial resistance, lead to adverse reactions from toxic or allergic reactions, and increase cost.
An approach to pink eye
In this meta-analysis, authors reviewed 32 studies to determine the relative prevalence of bacterial versus viral conjunctivitis and the diagnostic accuracy of various signs and symptoms associated with each condition. In children, bacterial conjunctivitis appeared to be more common (71%) while in adults, viral conjunctivitis was more common (78%). However, these estimates were limited by small studies, wide confidence intervals, and scant evidence.
The symptoms and signs associated with a higher likelihood of viral conjunctivitis were presence of pharyngitis (LR+ 5.4-9.9), pre-auricular lymphadenopathy (LR+ 2.5-5.6), and contact with another person with red eye (LR+ 2.5). Bacterial conjunctivitis was more likely with mucopurulent discharge (LR+ 2.1) and otitis media in a child (LR+ 2.5). These likelihood ratios were based on data from relatively few high-level methodological studies and, unfortunately, no single clinical sign or symptom could differentiate bacterial and viral conjunctivitis with any certainty.
Does This Patient With Acute Infectious Conjunctivitis Have a Bacterial Infection?: The Rational Clinical Examination Systematic Review. JAMA. 2022 Jun 14;327(22):2231-2237. doi: 10.1001/jama.2022.7687.