Infectious Conjunctivitis

Infectious conjunctivitis is one of the most common causes of red eye. Infectious conjunctivitis is commonly caused by bacterial or viral infection.
I. Pathophysiology
A. The clinical term "red eye" is applied to a variety of distinct infectious or inflammatory
diseases of the eye. Conjunctivitis is the most common cause of red eye. Conjunctivitis
consists of inflammation of the conjunctiva, which is caused by a broad group of conditions.
The inflammation can be infectious or noninfectious in origin.
B. Most frequently, conjunctivitis is caused by a bacterial or viral infection. Sexually
transmitted diseases such as chlamydial infection and gonorrhea are less common causes
of conjunctivitis. Ocular allergy is a major cause of chronic conjunctivitis.






II. Clinical Evaluation of Conjunctivitis
A. An ocular, medical and medication history should establish whether the condition is acute,
subacute, chronic or recurrent, whether it is unilateral or bilateral.
B. Discharge
1. A serous discharge (watery) is most commonly associated with viral or allergic ocular
conditions.
2. A mucoid (stringy or ropy) discharge is highly characteristic of allergy or dry eyes.
3. A mucopurulent or purulent discharge, often associated with morning crusting and
difficulty opening the eyelids, strongly suggests a bacterial infection. The possibility of
Neisseria gonorrhoeae infection should be considered when the discharge is copiously
purulent.
C. Itching is highly suggestive of allergic conjunctivitis. In general, a red eye in the absence
of itching is not caused by ocular allergy. A history of recurrent itching or a personal or
family history of hay fever, allergic rhinitis, asthma or atopic dermatitis is also consistent
with an ocular allergy.
D. Unilateral or Bilateral Conjunctivitis
1. Allergic conjunctivitis is almost always secondary to environmental allergens and,
therefore, usually presents with bilateral symptoms. Infections caused by viruses and
bacteria are transmissible by eye-hand contact. Often, these infections initially
present in one eye, with the second eye becoming involved a few days later.
2. Pain, Photophobia and Blurred Vision
a. Pain and photophobia do not usually occur with conjunctivitis, and these findings
suggest an ocular or orbital disease processes, including uveitis, keratitis, acute
glaucoma and orbital cellulitis.
....CLICK HERE TO DOWNLOAD FULL ARTICLE