Infectious conjunctivitis is inflammation of the conjunctiva usually caused by viruses or bacteria.
Bacteria and viruses can infect the conjunctiva.
Redness and tearing or discharge are common symptoms, and some people have sensitivity to light.
The diagnosis is usually based on the person's symptoms and the appearance of the eyes.
Antibiotic eye drops are often given for bacterial conjunctivitis.
Good hygiene helps prevent the infection from spreading to the other eye or to someone else's eye.
A variety of microorganisms may infect and cause inflammation in the conjunctiva (the membrane that lines the eyelid and covers the white of the eye). The most common organisms are viral, particularly those from the group known as adenoviruses. Bacteria can also cause infections.
Both viral and bacterial conjunctivitis are very contagious, easily passing from one person to another, or from a person's infected eye to the uninfected eye.
Inflammation of the conjunctiva (conjunctivitis) that is caused by an allergic reaction, as opposed to a virus or bacteria, is called allergic conjunctivitis.
Sometimes, severe conjunctival infections spread to the cornea (the clear layer in front of the iris and pupil).
An Inside Look at the Eye
Causes of Infectious Conjunctivitis
Viruses
Bacteria
Conjunctivitis in newborns is caused by Chlamydia trachomatis or Neisseria gonorrhoeae. Newborns are exposed to these bacteria in the mother's birth canal during labor and delivery.
Inclusion conjunctivitis is a particularly long-lasting form of conjunctivitis caused by certain strains of the bacterium Chlamydia trachomatis. Inclusion conjunctivitis usually spreads by sexual contact with a person who has a genital chlamydial infection. Rarely, inclusion conjunctivitis is acquired from contaminated, incompletely chlorinated swimming pool water.
Trachoma is another type of conjunctivitis caused by Chlamydia trachomatis. However, it is not spread through sexual contact with a person who has a genital chlamydial infection.
Gonococcal conjunctivitis is conjunctivitis caused by Neisseria gonorrhoeae (gonorrhea), a sexually transmitted infection that also may spread to the eye by contact with genital secretions from a person who has a genital gonorrheal infection.
Other causes
Fungal infections are rare and occur mainly in people who use corticosteroid eye drops for a long time or have eye injuries involving organic matter, such as plants or dirt.
Symptoms of Infectious Conjunctivitis
When infected by any microorganism, the conjunctiva becomes pink because of dilated blood vessels, and a discharge appears in the eye. Often the discharge causes the person's eyes to stick shut, particularly overnight. This discharge may also cause the vision to blur. Vision improves when the discharge is blinked away. If the cornea is infected, vision also blurs but does not improve with blinking. Sometimes the eye feels irritated, and bright light may cause discomfort. Very rarely, severe infections that have scarred the conjunctiva lead to abnormalities in the tear film, long-term vision difficulties, or both.
Viral conjunctivitis differs from bacterial conjunctivitis in the following ways:
Eye discharge tends to be watery in viral conjunctivitis and thicker white, green, or yellow in bacterial conjunctivitis.
An upper respiratory infection increases the likelihood of a viral cause.
A lymph node in front of the ear may be swollen and painful in viral conjunctivitis but is usually not in bacterial conjunctivitis.
These factors, however, cannot always accurately differentiate viral conjunctivitis from bacterial conjunctivitis.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
People with inclusion conjunctivitis or with conjunctivitis caused by gonorrhea also often have symptoms of a genital infection, such as discharge from the penis or vagina and burning during urination.
Reprinted with permission of the American Academy of Ophthalmology, Eye Trauma and Emergencies: A Slide-Script Program, 1985.
Conjunctivitis in the newborn causes inflammation of the eyelid and a discharge of pus from both eyes.
Diagnosis of Infectious Conjunctivitis
A doctor's evaluation of the symptoms and appearance of the eye
Sometimes culture of secretions
Doctors diagnose infectious conjunctivitis usually by its symptoms and appearance. The eye is usually closely examined with a slit lamp (an instrument that enables a doctor to examine the eye under high magnification). Samples of infected secretions may be sent to a laboratory to identify the infecting organism with a culture. However, doctors usually send samples to a laboratory only in certain situations:
When the symptoms are severe or recurring
When the doctors are uncertain if a bacterial infection is present
When Chlamydia trachomatis or Neisseria gonorrhea is thought to be the cause
When the person has an immune system defect, such as advanced HIV infection (also called AIDS)
When the person has had an eye problem, such as a corneal transplant or eye bulging caused by Graves disease
Treatment of Infectious Conjunctivitis
For the discharge of bacterial conjunctivitis, warm, wet compresses
For treating the infection of bacterial conjunctivitis, antibiotic eye drops or ointment
For severe viral conjunctivitis, sometimes corticosteroid eye drops
For decreasing the symptoms (swelling and discomfort) of viral conjunctivitis, cold compresses
Frequent use of hand sanitizers and other precautions to avoid spreading the infection
Because infectious (bacterial or viral) conjunctivitis is highly contagious, people should use hand sanitizers or wash their hands thoroughly before and after cleaning the eye or applying medications to the eye. Also, a person should be careful not to touch the infected eye and then touch the other eye. Towels and washcloths used to clean the eye should be kept separate from other towels and washcloths.
People with infectious conjunctivitis generally stay home from work or school for a few days, just as they would with a cold. In the most severe cases of viral conjunctivitis, people sometimes stay home for weeks. People with conjunctivitis should avoid swimming in a pool.
Conjunctivitis caused by bacteria
If discharge accumulates on the eyelid, people should gently wash the eyelid (with the eye closed) with warm tap water and a clean washcloth.
Antibiotics are helpful only for bacterial conjunctivitis. However, because it is sometimes difficult to distinguish between bacterial and viral infections, some doctors prescribe antibiotics for everyone with conjunctivitis. Antibiotic eye drops or ointments, such as moxifloxacin, ciprofloxacin, or trimethoprim/polymyxin, which are effective against many types of bacteria, are used for 7 to 10 days. Drops are usually effective, but ointments are sometimes used because they last longer if the eye is watering a lot. Some people may not want to use ointments because they can blur vision for up to 20 minutes after they are applied. Antibiotics are helpful only for bacterial conjunctivitis. However, because it is sometimes difficult to distinguish between bacterial and viral infections, some doctors prescribe antibiotics for everyone with conjunctivitis. Antibiotic eye drops or ointments, such as moxifloxacin, ciprofloxacin, or trimethoprim/polymyxin, which are effective against many types of bacteria, are used for 7 to 10 days. Drops are usually effective, but ointments are sometimes used because they last longer if the eye is watering a lot. Some people may not want to use ointments because they can blur vision for up to 20 minutes after they are applied.
Adult inclusion conjunctivitis requires antibiotics, such as azithromycin, doxycycline, or erythromycin, which are taken by mouth. These medications also cure the genital infection. A person's sex partners should also receive treatment.requires antibiotics, such as azithromycin, doxycycline, or erythromycin, which are taken by mouth. These medications also cure the genital infection. A person's sex partners should also receive treatment.
Gonococcal conjunctivitis may be treated with a single injection of ceftriaxone and a single dose of azithromycin (or doxycycline for 1 week) taken by mouth. may be treated with a single injection of ceftriaxone and a single dose of azithromycin (or doxycycline for 1 week) taken by mouth.
Conjunctivitis in newborns is prevented by routinely giving silver nitrate eye drops (not available in the United States) or erythromycin ointment to all infants at birth. If an infection develops despite these treatments, newborns are given medications depending on which bacterium is causing the infection. Infections caused by is prevented by routinely giving silver nitrate eye drops (not available in the United States) or erythromycin ointment to all infants at birth. If an infection develops despite these treatments, newborns are given medications depending on which bacterium is causing the infection. Infections caused byNeisseria gonorrhoeae are treated with ceftriaxone given by vein (intravenously) or injected into a muscle or a single dose of cefotaxime. Infections caused by are treated with ceftriaxone given by vein (intravenously) or injected into a muscle or a single dose of cefotaxime. Infections caused byChlamydia trachomatis are treated with erythromycin or azithromycin. The parents should also be treated.are treated with erythromycin or azithromycin. The parents should also be treated.
Conjunctivitis caused by viruses
Cold compresses sometimes soothe the feeling of irritation caused by viral conjunctivitis.
Most people with viral conjunctivitis get better in 1 to 3 weeks and do not need any specific treatment. However, corticosteroid eye drops may be needed in some people who have severe eye pain with exposure to bright light or whose vision is affected and in people with epidemic keratoconjunctivitis (see What Is Pink Eye?), particularly in those in whom blurring and glare (starbursts or halos around lights) are interfering with important activities.
Antiviral eye drops are not helpful for conjunctivitis caused by viruses (antiviral eye drops are used for some cornea infections caused by viruses—see Herpes Simplex Keratitis).
In severe cases, the doctor may remove the inflamed membrane that lines the inner eyelid to reduce the chances of scarring of the conjunctiva.
Prognosis for Infectious Conjunctivitis
Most people with infectious conjunctivitis eventually get better without treatment. However, some infections, particularly those caused by some bacteria, may last a long time if not treated.
Inclusion conjunctivitis may persist for months if not treated.
Conjunctivitis in newborns may cause blindness if not treated.
