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Overview of Conjunctivitis


Zeba A. Syed

, MD, Wills Eye Hospital

Reviewed/Revised Apr 2023
Topic Resources

Conjunctival inflammation typically results from infection, allergy, or irritation. Symptoms are conjunctival hyperemia and ocular discharge and, depending on the etiology, discomfort and itching. Diagnosis is clinical; sometimes cultures are indicated. Treatment depends on etiology and may include topical antibiotics, antihistamines, mast cell stabilizers, and corticosteroids.

Symptoms and Signs of Conjunctivitis

Any source of inflammation can cause lacrimation or discharge and diffuse conjunctival vascular dilation. Discharge may cause the eyes to crust overnight. Thick discharge may blur vision, but once discharge is cleared, visual acuity should be unaffected.

Diagnosis of Conjunctivitis

  • Clinical evaluation

  • Sometimes culture

Usually, diagnosis of conjunctivitis is made by history and examination (see table ), usually including slit-lamp Slit-lamp examination The eye can be examined with routine equipment, including a standard ophthalmoscope; thorough examination requires special equipment and evaluation by an ophthalmologist. History includes location... read more examination with fluorescein staining of the cornea and, if glaucoma Overview of Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage in which an important part is a relative increase in intraocular pressure (IOP) that can lead to irreversible... read more is suspected, measurement of intraocular pressure. In order to prevent transmitting infection to other patients and to staff, meticulous disinfection of equipment that touches the eye is particularly important after examination of patients who could have conjunctivitis.

Other disorders can cause a red eye Red Eye Red eye refers to a red appearance of the opened eye, reflecting dilation of the superficial ocular vessels. Dilation of superficial ocular vessels can result from Infection Allergy Inflammation... read more . Deep pain in the affected eye when a light is shone in the unaffected eye (true photophobia) does not occur in uncomplicated conjunctivitis and suggests a disorder of the cornea or anterior uvea. Circumcorneal conjunctival hyperemia (sometimes described as ciliary flush) is caused by dilated, fine, straight, deep vessels that radiate out 1 to 3 mm from the limbus, without significant hyperemia of the bulbar and tarsal conjunctivae. Ciliary flush occurs with uveitis Overview of Uveitis Uveitis is defined as inflammation of the uveal tract—the iris, ciliary body, and choroid. However, the retina and fluid within the anterior chamber and vitreous are often involved as well.... read more Overview of Uveitis , acute glaucoma Overview of Glaucoma Glaucomas are a group of eye disorders characterized by progressive optic nerve damage in which an important part is a relative increase in intraocular pressure (IOP) that can lead to irreversible... read more , and some types of keratitis (see Corneal Disorders Introduction to Corneal Disorders Symptoms that suggest corneal involvement (eg, rather than simple conjunctivitis) include unilateral involvement, pain (foreign body sensation and ache—not just a gritty sensation), particularly... read more ) but not with uncomplicated conjunctivitis.

Pearls & Pitfalls

  • Suspect another cause of red eye (eg, uveitis, glaucoma, keratitis) if patients have true photophobia, loss of vision, or ciliary flush and do not have significant discharge or tearing.

The cause of conjunctivitis is suggested by clinical findings. However, cultures are indicated for patients with severe symptoms, immunocompromise, a vulnerable eye (eg, after a corneal transplant, in exophthalmos Proptosis This photo shows a woman's slightly bulging left eye (proptosis), caused by a meningioma. Proptosis is protrusion of the eyeball. Exophthalmos means the same thing, and this term is usually... read more Proptosis due to Graves disease Etiology Etiology ), or poor response to initial therapy.

Clinical differentiation between viral and bacterial infectious conjunctivitis is not highly accurate. However, if the history and examination strongly suggest viral conjunctivitis, withholding antibiotics initially is appropriate. Antibiotics can be prescribed later if the clinical picture changes or if symptoms persist.


Treatment of Conjunctivitis

  • Prevention of spread

  • Treatment of symptoms

  • Antibiotics if cause is bacterial

  • Topical antihistamines and mast cell stabilizers if cause is allergic

Clinicians must take the following steps to avoid transmitting conjunctivitis, which is most often highly contagious and spread by droplets, fomites, and hand-to-eye inoculation:

  • Use hand sanitizer or wash their hands properly (fully lather hands, scrub hands for at least 20 seconds, rinse well, and turn off the water using a paper towel)

  • Disinfect equipment after examining patients

Patients should do the following:

  • Use hand sanitizer and/or wash their hands thoroughly after touching their eyes or nasal secretions

  • Avoid touching the noninfected eye after touching the infected eye

  • Avoid sharing towels or pillows

  • Avoid swimming in pools

Eyes should be kept free of discharge and should not be patched. Small children with conjunctivitis should be kept home from school to avoid spreading the infection. Cool washcloths applied to the eyes may help relieve local burning and itching. Antimicrobials are used for certain infections.

Viral conjunctivitis is typically self-limited, but severe cases sometimes require topical corticosteroids.

Allergic conjunctivitis is treated with topical antihistamines, nonsteroidal anti-inflammatory drugs, mast cell stabilizers, or a combination. Topical corticosteroids or cyclosporine are used for recalcitrant cases. Oral antihistamines may be helpful for patients with other allergic symptoms (eg, rhinorrhea).

Key Points

  • Conjunctivitis typically results from infection, allergy, or irritation.

  • Infectious conjunctivitis is usually highly contagious.

  • Typical findings are redness (without ciliary flush) and discharge, without significant pain or loss of vision.

  • Diagnosis is usually clinical.

  • Treatment includes measures to prevent spread and treatment of the cause (eg, sometimes antimicrobials).

Drugs Mentioned In This Article

Drug Name Select Trade
AK-Fluor, Bio Glo, Fluorescite, Fluorets , Fluor-I-Strip, Fluor-I-Strip A.T., Ful-Glo, Ophthalmicflur
Cequa, Gengraf , Neoral, Restasis, Sandimmune, SangCya, Verkazia, Vevye
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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