Conjunctivitis is inflammation of the conjunctiva. The conjunctiva is a layer that covers and protects the inside of the eyelids and the front part of the sclera (the white part of the eyes).


Signs and symptoms of conjunctivitis include inflammation of the conjunctiva and red eyes dues to the blood vessels getting filled with blood. Blood vessels are tube-shaped structures that carry blood to and from the heart. The blood vessels in the conjunctiva are very small. Although the inflammation in conjunctivitis usually is not painful, it can cause discomfort such as itching and scratchiness.

People with conjunctivitis sometimes feel like sand is in the eye and rubbing the eye will not make the discomfort go away. This is because rubbing of the eye causes the release of chemicals, which makes the eyes itch more. Discomfort is usually the first symptom, followed by redness and inflammation. Some people with conjunctivitis also develop ear infections because similar types of bacteria cause both conditions. In some cases, people with conjunctivitis begin to dislike bright lights because the lights irritate the eye more.

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In conjunctivitis, a fluid-like substance sometimes comes out of the eye(s), which is usually white, yellow, or green. This usually occurs about a day after the discomfort, redness, and inflammation. This fluid tends to be thick and contains pus in people with bacteria infections, which may cause the eyelids to stick together in the morning. Pus is a yellow or green creamy substance sometimes found at the site of infections.

In cases of conjunctivitis caused by a virus, the fluid tends to be less thick (sometimes watery) and may sometimes be clear. Viral caused conjunctivitis is usually associated with a cold, sore throat, and infections of the upper respiratory tract (nose, throat, sinuses, and larynx). Sinuses are openings in the bone that often contain fluid. The larynx is an organ located at the upper part of the windpipe that produces voice.

In cases of conjunctivitis caused by allergies, the fluid-like substance that comes out of the eye is clear and the eyelids are often swollen. Allergic conjunctivitis usually occurs in both eyes. Conjunctivitis caused by bacteria or a virus tends to start in one eye, but can quickly spread to the other.


Yes. Conjunctivitis is a very common condition in the United States. In fact, every year at least 1 in 50 people are thought to visit doctor due to this condition. Conjunctivitis has been estimated to represent 30% of all eye complaints. Conjunctivitis is the most common infection of the eye that affects children. Approximately 15% of the U.S. population will develop conjunctivitis due to allergies at some point. Conjunctivitis is very uncommon in other countries.


There are many different causes of conjunctivitis, most of which are not very serious. Conjunctivitis can be caused by bacteria or virus infections, especially in children. Since the conjunctiva is a wet substance, it is easy for substances that would cause infections to stick to it. When this happens, these substances can build up and overwhelm the normal defense systems of the body. Viral conjunctivitis is more common in the early fall and late spring.

Types of bacteria that often cause conjunctivitis include staphylococci and streptococci (you may have heard them referred to as staph infections and strept infections). The type of bacteria involved will determine how severe the condition is. Some newborn babies develop an infection that leads to conjunctivitis known as neonatal opthalmia. This condition can be very serious since it can spread throughout the entire body and cause blindness. However, most cases of conjunctivitis do not cause danger to the eye or problems with vision.

Neonatal opthalmia occurs during birth as the child becomes infected with bacteria from the mother's cervix. The cervix is a small, cylinder-shaped organ that forms the lower part and neck of the uterus. The uterus is a hollow organ in a female's body where the egg is implanted and the baby develops.

There are many different types of bacteria that can cause neonatal opthalmia. It can be caused by the same bacteria that lead to gonorrhea or genital herpes. Gonorrhea and genital herpes are common bacterial infections transmitted during sex. It can also be caused by the same bacteria that lead to chlamydial infections. Chylmamydiae are tiny organisms that cause various types of infections. It often occurs in a woman's reproductive organs. In some tropical countries, a type of chlamydial infection can cause a serious form of conjunctivitis known as trachoma.

Another form of conjunctivitis is known as keratoconjunctivitis. In this condition, which is often caused by a virus, both the conjunctiva and the cornea are inflamed. The cornea is the clear covering at the front of the eyeball. The cornea can be seen in the picture on the top of this page. Conjunctivitis can be caused by fungus and parasites. A parasite is an organism that lives in or on another organism to obtain nourishment. A fungus is a type of parasite.

Conjunctivitis can also be caused by allergies or something in the environment that irritates the eye, such as chemicals, dust, or smoke. Allergies are a more common cause of conjunctivitis in adults than children. Makeup can often cause allergic reactions that leads to conjunctivitis, as can perfume, medications, pollen, and the fluid that is used to clean contact lenses. Pollen is a dusty substance found in some plants that helps them reproduce.

Allergic conjunctivitis can occur during specific seasons and is due to specific types of pollens. This type of conjunctivitis is known as seasonal allergic conjunctivitis. It generally occurs in the spring due to grass pollen or in the late summer months due to ragweed pollen. However, allergic conjunctivitis can also be occur year-round (known as perennial allergic conjunctivitis), and is usually due to dust, animal skin, or dead skin flakes that fall off of an animal's hair or feathers. Year round allergic conjunctivitis can also be due to other allergy-causing substances that are present in the air all or most of the year.


Conjunctivitis is diagnosed by having a doctor look at the appearance of the eye, usually with a type of microscope. By taking a sample of the fluid-like substance that comes out of the eyes and testing it in a laboratory, a doctor can often tell what has caused the condition. Doctors are especially sure to do this in the case of newborn babies with conjunctivitis. Some doctors use special, bright eye drops to make the diagnosis of conjunctivitis because it helps them examine the eye better.


With the exception of the allergic form of conjunctivitis, most types of conjunctivitis are contagious and spread very easily. Conjunctivitis can be spread by hand to eye contact, by viruses associated with a cold, various illnesses, or sore throat. One type of illness that can spread conjunctivitis is the measles. Measles is a viral illness that leads to a fever and a characteristic rash. Conjunctivitis that is caused by a virus can spread quickly, affecting large groups of people at once.


Yes. An important step to preventing conjunctivitis from spreading to others is to wash your hands, face, and hair often. This helps keep the body clean and prevents the buildup of any allergy-causing substances. This applies to people with conjunctivitis and to people without it. People with conjunctivitis should wash the hands before and after touching the eye. The non-infected eye should not be touched because if the condition is caused by an infection it may spread to that eye. Any clothes that have made contact with the affected eye(s) should be washed, as should towels and pillowcases.

Doorknobs and counter surfaces should be disinfected with a combination of part bleach and mostly water. Swimming should be avoided because the bacteria can spread in the water. Shaking hands should also be avoided, as should sharing towels, washcloths, and clothes. Sharing makeup should also be avoided. Tissues should be used as opposed to handkerchiefs and the tissues should be thrown directly into the garbage after use.

If conjunctivitis is caused by an infection, used makeup should be thrown away and replaced to prevent it from reoccurring or spreading. Individuals can prevent conjunctivitis by avoiding substances that cause allergic reactions in them. People who have conjunctivitis caused by pollen can help themselves do this by closing the windows during the pollen season and using the air conditioner instead. Pollen is a dusty substance found in some plants that helps them reproduce. Some cars even have filters that can remove pollen from the incoming air. Mowing the lawn and gardening should be avoided to reduce exposure to pollen. This is particularly true in the early afternoon and the morning when pollen counts are usually highest.

Treatment for conjunctivitis (pictured to the right) will depend on what has caused it. An opthalmologist is the type of doctor that is trained to treat this condition. An ophthalmologist is a medical doctor that specializes in ophthalmology, which is the science that deals with the structure, functions, and diseases of the eye, and the diagnosis and treatment of such diseases.

The medication used to treat conjunctivitis often comes in the form of eye drops. In some cases, an antibiotic needs to be used, which is a medication that fights against infections. Antibiotics are usually given that can destroy a large group of different types of bacteria. However, medications may sometimes be chosen that fight off a specific type of bacteria.

Doctors will often give antibiotics to treat conjunctivitis without testing to see what the exact cause is. Even without antibiotic treatment, however, the condition often goes away in four to five days. To avoid complications, however, it is best to see a doctor when conjunctivitis occurs. People with weakened defense systems in their body are more likely to develop severe cases of conjunctivitis that can threaten their vision.

Antibiotics will not be helpful in getting rid of conjunctivitis that is caused by a virus, which tends to go away by itself in about three weeks. For this reason, conjunctivitis caused by a virus is generally considered less serious than conjunctivitis caused by bacteria. However, the signs and symptoms of viral conjunctivitis can often be relieved with cold compresses and artificial tears (which can be purchased in most pharmacy stores).

For the worst types of cases caused by a virus, a type of drug known as corticosteroids may be used as treatment because they help to reduce inflammation. Corticosteroid eye drops are only used when the doctor is sure that infections have not caused the conjunctivitis. The reason for this is that if corticosteroids are used when conjunctivitis is caused by an infection, it can actually make the condition worse.
In mild cases of allergic conjunctivitis, there is no cure except for avoiding what caused the allergic reaction. However, cool compresses and artificial tears sometimes relieve the discomfort. More severe cases of conjunctivitis caused by allergies can be treated with allergy shots or eye drops that contain antihistamine. Histamine is a natural substance in the body that is released during allergic reactions and leads to many allergic symptoms. Substances that block the effects of histamine are known as antihistamines and they can also be taken by mouth.

Antihistamines that are taken by mouth may offer partial relief of symptoms, yet can take about an hour or more before beginning to work and can cause irritability, drowsiness, and dryness. They work best when taken before being exposed to whatever causes the allergic reaction, such as pollen. However, exposure to pollen is often difficult to predict. Antihistamine eye drops provide immediate relief with barely any side effects.

Some patients with allergic conjunctivitis are prescribed corticosteroid eye drops (discussed in the last paragraph) or different forms of medications that decrease inflammation, known as non-steroidal anti-inflammatory medications (abbreviated as NSAIDs). If you wear contact lenses and have allergic conjunctivitis, the doctor can help you find ways to make wearing these lenses more comfortable.

If the cause of conjunctivitis is chemical exposure, doctors suggest washing the eyes out with lots of water and getting to an emergency room immediately. Most of the damage that occurs to the eyes happens on the first few minutes after being exposed to the chemicals. Thus, the faster the eyes are flushed out, the better.

Warm water is often used to wash away the fluid-like substance that comes out of the eyes during conjunctivitis and to remove any crust associated with it. In babies, doctors usually wash the babies eyes with a clean form of salt water. This intervention usually only provides temporary relief, however.


Conjunctivitis is also known as pinkeye and blennopthalmia.


Conjunctivitis comes from the Latin word "conjunctivus" meaning "connecting," and the Greek word "itis" meaning "inflammation." Put the two words together and you have "connecting inflammation."