What causes conjunctivitis?

Pink Eye Facts (Conjunctivitis)


What is "pink eye"?

Pink eye or conjunctivitis, is redness and inflammation of the membranes (conjunctiva) covering the whites of the eyes and the membranes on the inner part of the eyelids. These membranes react to a wide range of bacteria, viruses, allergy-provoking agents, irritants, and toxic agents, as well as to underlying diseases within the body. Viral and bacterial forms of conjunctivitis are common in childhood, but they occur in adults as well. Pink eye can occur in people of any age. Overall, however, there are many causes of pink eye. These can be classified as either infectious or noninfectious. Pink eye does not cause any changes in vision.


What infections cause pink eye, what are infectious pink eye symptoms, and how are they treated?

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Viral pink eye

The leading cause of a red, inflamed eye is virus infection. Adenoviruses are the type of virus that are most commonly responsible for the infection. Viral pink eye symptoms are usually associated with more of a watery discharge that is not green or yellow in color. Viral pink eye is most common in late fall and early spring. Often, viral "cold-like" symptoms, such as sinus congestion and runny nose, are also present. The eyelids may be swollen. Sometimes looking at bright lights is painful.

While viral pink eye may not require an antibiotic, those affected should see a doctor, as occasionally this form of pink eye can be associated with infection of the cornea (the clear portion of the front of the eyeball). This infection must be correctly detected and treated. Viral pink eye is highly contagious. The symptoms of viral pink eye can last one to two weeks. Symptoms are pronounced for the first three to five days after symptoms appear, with slow resolution over the following one to two weeks.

Bacterial pink eye

Staphylococci and Streptococci, among others, are types of bacteria that commonly cause pink eye. Symptoms of pink eye caused by bacteria occur rapidly and can include eye pain, swelling, itching, redness,
a moderate to large amount of discharge, usually thick and yellow or greenish in color,
swelling of the lymph nodes in front of the ears.
The discharge commonly accumulates after sleeping. Affected children may awaken most unhappy that their "eyes are stuck shut," requiring a warm washcloth applied to the eyes to remove the discharge. Bacterial pink eye is treated by repeated warm washcloths applied to the eyes (try applying these to your child's eye one eye at a time during a favorite video) and requires antibiotic eyedrops or ointment prescribed by the doctor.

Picture of Pink Eye or Conjunctivitis
What does pink eye look like?

Be careful not to use medication prescribed for someone else, or from an old infection, as these may be inappropriate for your current infection or may have been contaminated from other infections by accidentally touching the medicine bottle to infected areas. A safe, effective, and potentially less frightening method of putting drops into the eyes involves asking your child to lie down flat, with instructions to merely "close your eyes," and placing the recommended number of drops in the inner corner of the eye, next to the bridge of the nose, and letting them make a little "lake" there. When your child relaxes and opens the eyes, the medicine will flow gently into the infected mucous membranes without the need to "force open" the eyes.

When you feel that you or your child might have bacterial pink eye, it is very important to see your doctor immediately for several reasons. First, if the cause is a bacterial infection, an antibiotic will be needed to help the infection-fighting immune system to kill this infection. Secondly, if you are experiencing other symptoms such as a runny nose, cough, earache, etc., there is a good chance that these symptoms are caused by the same bacteria, and an oral antibiotic may also be needed to treat this infection along with the antibiotic drops or ointment for the eyes. Finally, your doctor will want to exclude the possibility that the infection has spread to areas where the symptoms may not yet be recognizable.