A 26-year-old man is evaluated for sudden onset of redness, watery discharge, and itching of both eyes. His vision is slightly distorted from excess tearing but is not blurred. He feels fine otherwise. Medical history is significant for obesity, asthma, sleep apnea, and chronic back pain. Eye examination shows bilateral injection with granular appearance of the conjunctiva. Mild eyelid swelling and clear discharge are also noted. Pupils are equally round and reactive to light. The lungs have a few scattered wheezes. What is the most likely diagnosis in this patient?
Acute conjunctivitis* | |||
Viral | Bacterial | Allergic | |
Distribution | Unilateral or bilateral | Unilateral or bilateral | Bilateral |
Discharge | Watery/mucoid | Purulent | Watery |
Conjunctival appearance | Diffuse injection; follicular ("bumpy") | Diffuse injection; nonfollicular | Diffuse injection; follicular ("bumpy") |
Associated findings | Viral prodrome | Unremitting discharge (reaccumulates within minutes) | Ocular pruritus, history of atopy (eg, allergic rhinitis, asthma) |
Duration | 1-2 weeks | 1-2 weeks | <30 minutes (often sudden onset) to perennial |
*Red flags suggestive of alternate etiology: decreased visual acuity, photophobia, pain with extraocular movement & fixed/distorted pupil. | |||
This patient has new-onset conjunctival injection and discharge, findings most commonly due to acute conjunctivitis. Conjunctivitis is characterized by inflammation of the conjunctiva, the mucous membrane that lines the inside of the eyelids (tarsal conjunctiva) and anterior sclera (bulbar conjunctiva).
Common causes of acute conjunctivitis include:
Allergic conjunctivitis: Patients develop bilateral conjunctival injection and watery discharge, as seen in this case. Because this condition is due to a type I hypersensitivity reaction to environmental allergens (eg, pollen, dust), ocular pruritus is characteristic and begins soon after exposure to the allergen, which may not always be readily identifiable; the sudden symptom onset in this case is consistent with the diagnosis. Eyelid edema (due to histamine release and rubbing) is common, and the tarsal conjunctiva may have a nonspecific, granular (follicular or "bumpy") appearance due to lymphoid aggregates. Findings suggestive of other atopic conditions, such as allergic rhinitis (eg, rhinorrhea, sneezing) and asthma (eg, wheezing), may be present (as in this patient) and are also often triggered by environmental allergens.
Viral conjunctivitis: Like allergic conjunctivitis, patients develop watery discharge and granular tarsal conjunctiva; upper respiratory symptoms (eg, rhinorrhea) usually accompany ocular findings. In contrast to allergic conjunctivitis, ocular pruritus is uncommon, making this diagnosis less likely in this patient (Choice E). Moreover, viral infections often start with unilateral conjunctival injection and involve the contralateral side within 1-2 days.
Bacterial conjunctivitis: Symptoms classically include unilateral conjunctival injection with thick, purulent discharge that reaccumulates within minutes of wiping; contralateral involvement often occurs within 1-2 days (Choices D).
The presence of severe pain, photophobia, or blurry vision (none of which is seen in this patient) should raise concern for a diagnosis other than conjunctivitis.
(Choice B) Inflammation of the anterior uveal tract causes iritis (or anterior uveitis). Redness of the eye is often associated with pain, photophobia, and decreased visual acuity, none of which are seen in this patient. In addition, discharge and pruritus are not expected.
(Choice C) Atopic keratoconjunctivitis is a form of allergic conjunctivitis in which redness, pruritus, and tearing are common, but patients have chronic (not acute) symptoms, often with photophobia and a foreign body sensation. Moreover, signs of chronic eyelid inflammation (eg, thickened, lichenified skin) are typical.
Educational objective:
Acute allergic conjunctivitis causes bilateral conjunctival injection with watery discharge and granular (follicular) tarsal conjunctiva. Ocular pruritus is a key feature that distinguishes allergic conjunctivitis from viral conjunctivitis.