Conjunctivitis is a nonspecific term used to describe inflammation of the ocular surface and conjunctiva from either infectious or noninfectious causes. Infectious conjunctivitis is most commonly due to exogenous inoculation of the mucous membranes lining the surface of the eye and eyelid, resulting in an activation of a local inflammatory response. The vast majority of cases are acute but may also present as chronic or recurrent. Although most cases of acute infectious conjunctivitis are self-limited and result in few long-term sequelae, appropriate evaluation and therapy are indicated with specific presentations.
The hallmark of conjunctivitis is injection or hyperemia of the conjunctival vessels, resulting in a red eye as well as tearing and/or mucopurulent discharge. Conjunctivitis may also result in complaints of irritation, foreign body sensation, mattering or crusting of the eyelids, and mild visual blurring primarily due to alterations of the tear layer. The local inflammatory response may manifest as conjunctival lymphoid follicles or vascular papillae, eyelid edema, and/or preauricular adenopathy. Complaints of severe eye pain, photophobia, significant visual loss, or referred pain should alert the examiner to the possibility of other, more ominous, etiologies. Similarly, loss of normal corneal clarity either diffuse or focal, proptosis, pupillary abnormalities, conjunctival scarring, or restriction of eye movement is criteria for a detailed ophthalmic evaluation (Table 11.1).