Differentiating between dry eye and allergic conjunctivitis can be a complicated and frustrating task. Patients often complain of non-specific symptoms like irritation and redness, giving clinicians few clues. Complicating matters even more, signs and symptoms of dry eye and allergic conjunctivitis do not always correlate, can be subjective or vague, often mimic each other or may actually overlap.

Ocular allergy and Dry Eye Syndrome do not share the same causative factors and treatment methods are significantly different, thus the ability to diagnose the proper etiology of each disorder is essential for the proper treatment of patients.

An allergic eye can exhibit almost indistinguishable signs and symptoms, masking itself as a presenting dry eye and has been defined, by many, as Secondary Allergic Dry Eye. Lipid disruption due to arachidonic acid, formed by the allergic cascade, affects tear fluid evaporation.

It is for this reason, all initial comprehensive dry eye examinations should include IgE tear testing to confirm or rule out the presence of an ocular allergen.