Conjunctivitis (pinkeye)

Conjunctivitis, commonly known as pinkeye, is a general term for an infection or allergic reaction that affects the conjunctiva (the membrane that lines the eyelids).


Causes/associated factors
Infectious conjunctivitis is typically caused by a viral or bacterial infection in the eye. Offending organisms may include adenovirus, staphylococcus, streptococcus and neisseria. Chlamydia infections may also cause conjunctivitis. Infectious conjunctivitis is most common in children.
Allergic conjunctivitis, or hay fever, is an allergic reaction to pollen or other airborne substances, such as dust, animal dander or smoke. Allergic conjunctivitis affects both the eyes and upper respiratory tract. It's often worse in the spring, summer and fall, when pollen counts are high.

A type of conjunctivitis known as ophthalmia neonatorum may develop at birth, through exposure to normal bacteria from the mother's birth canal. The routine use of antibiotic eye ointment shortly after birth has made this type of conjunctivitis rare in the United States.

Sometimes, a blocked tear duct may cause recurrent conjunctivitis or persistent tearing from the affected eye. Blocked tear ducts are most common in infants.


Transmission
Viral and bacterial conjunctivitis are highly contagious. If you have the infection in one eye, you may easily spread it to the other eye or other people. Children who have symptoms of conjunctivitis are often sent home from school or child care facilities.
Allergic conjunctivitis isn't contagious.


Signs/symptoms
Viral and bacterial conjunctivitis are characterized by discharge from one or both eyes. Viral conjunctivitis typically produces a watery or thin, light-colored discharge. Bacterial conjunctivitis often has a thick, yellow-green discharge that may cause the eyelids to crust shut while sleeping. Other eye symptoms may include:
redness
swollen eyelids
sensitivity to bright light
mild itching
gritty sensation
Allergic conjunctivitis typically causes a clear, watery discharge and intense itching in both eyes. Other allergy symptoms, such as sneezing and watery nasal discharge, may also develop.


Diagnosis
Your doctor will ask questions about your medical history and do a physical exam. A sample of the eye discharge may be analyzed to identify the specific organism causing the infection. This is most common for infants and people whose symptoms don't improve after two to three days of treatment.

Treatment
Treatment varies depending on the type of conjunctivitis.
For viral conjunctivitis, treatment is intended to relieve symptoms. Cold compresses may be soothing on the affected eye, and your physician may recommend over-the-counter artificial tears. Most cases of viral conjunctivitis clear up on their own within seven days. If you have conjunctivitis in one eye, use caution to keep it from spreading to the other eye. Wash your hands thoroughly after caring for your eyes. Be careful not to touch your eyes, and launder your washcloths, towels and bed linens in hot water once a day until your symptoms improve.

Bacterial conjunctivitis is often treated with a seven- to 10-day course of antibiotic eye drops, such as tobramycin (Tobrex), sulfacetamine sodium (Sulamyd) or ciprofloxacin (Ciloxan). Sometimes, an antibiotic ointment such as erythromycin is prescribed.
Warm compresses may be soothing on the affected eye. Although your symptoms may improve quickly, it's important to complete the entire course of medication to keep the infection from returning. You're considered infectious until you've taken the antibiotics for at least 24 hours and your symptoms noticeably improve.

If you wear contact lenses, you'll need to switch to glasses temporarily -- eye medications can stain or be absorbed into contact lenses. When your doctor gives you the OK to wear contacts again, disinfect them before use. If you use disposable contacts, buy a new pair.

As with viral conjunctivitis, use caution to keep the infection from spreading to the other eye. Wash your hands thoroughly after caring for your eyes. Be careful not to touch your eyes, and launder your washcloths, towels and bed linens in hot water once a day until your symptoms improve.


For allergic conjunctivitis, cold compresses on the eyes may provide some relief. Your doctor may prescribe one of many different types of eye drops to ease your symptoms, along with antihistamines, decongestants, mast cell stabilizers or steroids. It's best to avoid rubbing your eyes.

Complications
Left untreated, conjunctivitis can damage the cornea, the clear surface covering the central portion of the outer eye. This may lead to a corneal ulcer, or a sore on the cornea. In severe cases, the ulcer may lead to blindness.

Pregnancy-specific information
Pregnancy doesn't affect the risk of developing conjunctivitis.

Senior-specific information
With age, the immune system often becomes less effective. Older adults may become more vulnerable to infections, including the bacteria and viruses that can cause conjunctivitis.

Prevention
To help prevent the spread of bacterial or viral conjunctivitis, wash your hands often. Don't share eye cosmetics or other personal items that may come in contact with your eyes, and replace eye cosmetics -- particularly mascara -- every three months.