Differential diagnosis of bacterial, viral conjunctivitis not evidence-based, review finds

The idea that certain signs and symptoms have diagnostic power to differentiate bacterial from viral conjunctivitis seems "not to be based on evidence,” according to a literature review.

General practitioners who prescribe antibiotics for conjunctivitis leave more than half of patients with acute infectious conjunctivitis taking unnecessary and not-always-effective antibiotic treatment, the study authors suggested. They said more research is warranted to provide general practitioners with easy-to-use diagnostic tools to differentiate the two types of conjunctivitis and to tailor appropriate antibiotic regimens.

Remco P. Reitveld and colleagues in Amsterdam and Zurich reviewed the current literature to determine whether current methodology for differential diagnosis of conjunctivitis is useful for the general practitioner. After searching 6,872 references, the authors found one eligible study, but the study “seemed methodologically unsound,” they wrote in the October issue of BMJ.

The involvement of one eye followed a few days later by the other eye and the presence of an enlarged preauricular node are said to be signs of viral conjunctivitis, the authors note. When the contralateral eye is involved 24 to 48 hours later, the diagnosis tends to be bacterial.

“In most treatment trials on bacterial conjunctivitis, the defined criteria for inclusion are purulent or mucopurulent discharge and conjunctival hyperemia. How evidence-based are these assertions?” the authors wrote.

They call for more research into the differences of signs and symptoms between the two types of conjunctivitis and the creation of easier diagnostic tools to make prescribing antibiotics more effective.