It often is associated with conjunctivitis. Discharge can be expressed from the canaliculus. Conjunctivitis is characterized by vascular dilation, cellular infiltration, and exudation. Allergic disease often has papillary projections and pruritus in individuals with a history of allergic disease. Viral infections tend to have lymphoid follicles on the undersurface of the lid and enlarged tender preauricular nodes.
Bacterial disease tends to have more purulent discharge.
Differentiating these different types is imprecise, requiring the physician to assume that a bacterial etiology is involved when unclear. Patients may have decreased visual acuity and photophobia. They often complain of severe eye pain. An epithelial defect may be evident on slit lamp examination or may require staining with fluorescein. Corneal inflammation or infection may be accompanied by anterior chamber reaction.