What is the first-line treatment for a 4-week-old infant with persistent conjunctivitis and excessive tearing?

In the case of a 4-week-old infant with persistent conjunctivitis and excessive tearing, the most appropriate first-line treatment is to perform nasolacrimal massage. This approach is often recommended when the symptoms are indicative of nasolacrimal duct obstruction, which is common in infants and can present as unilateral conjunctivitis and excessive tearing.

By using gentle digital massage over the area of the nasolacrimal duct, parents or caregivers can help to open the obstructed duct and promote normal drainage of tears, which may resolve both the tearing and conjunctivitis without the need for medications. It is a simple and non-invasive first step that can be effective, especially in cases where the symptoms are mild and there is no indication of a bacterial infection.

Other treatment options like topical antibiotics, warm compresses, and referral to an ophthalmologist are generally considered in cases where there is suspicion of infection or if the condition does not improve with conservative measures, but nasolacrimal massage is the standard initial management for nasolacrimal duct obstruction in young infants.