A physician will conduct a physical examination. Parents will be asked to provide information about the child’s medical history and list of symptoms. This information is crucial to helping the physician distinguish whether conjunctivitis is nonallergic or related to an allergy.

In evaluating a newborn, a physician will ask the parent for a full prenatal history. Likely questions include those about developmental delays, maternal infections (e.g., herpes simplex virus, chlamydia, human immunodeficiency virus [HIV]), and any complications with delivery. Some medications given to infants at childbirth, including silver nitrate (an ophthalmic antiseptic used to treat chlamydial infection) and erythromycin (an antibiotic), also are known to cause eye irritation.

When examining an older child, the physician will ask about potential exposure to individuals at home or in school who might have upper respiratory tract infections or conjunctivitis. In teens, a sexual history can potentially uncover the source of eye problems due to sexually transmitted chlamydial or neisserial infections. Questions about cosmetics or contact lens use also might reveal valuable information.

If nonallergic possibilities are ruled out and an allergy or allergic conjunctivitis is suspected, the physician will ask about environmental factors (including exposure to tobacco smoke, pets, carpets and drapes that collect dust, etc.) and time of onset (seasonal or perennial). Symptoms such as itchy eyes and stringy or ropy discharge are strongly indicative of an allergy diagnosis.

A physician may also request a vision check, observe a child’s eye motion, look for physical manifestations on the eyelids and test the reaction of pupils to light.

To confirm an allergy diagnosis, allergy testing also may take place.