Topic Overview

Pink eye (also called conjunctivitis) is redness and swelling of the conjunctiva, the mucous membrane that lines the eyelid and eye surface. The lining of the eye is usually clear. If irritation or infection occurs, the lining becomes red and swollen. See pictures of a normal eye and an eye with conjunctivitis.

Pink eye is very common. It usually is not serious and goes away in 7 to 10 days without medical treatment.

Common symptoms of pink eye are:

• Eye redness (hyperemia).
• Swollen, red eyelids.
• More tearing than usual.
• Feeling as if something is in the eye (foreign-body sensation or keratoconjunctivitis).
• An itching or burning feeling.
• Mild sensitivity to light (photophobia).
• Drainage from the eye.

Most cases of pink eye are caused by:

• Infections caused by viruses or bacteria.
• Dry eyes from lack of tears or exposure to wind and sun.
• Chemicals, fumes, or smoke (chemical conjunctivitis).
• Allergies.

Viral and bacterial pink eye are contagious and spread very easily. Since most pink eye is caused by viruses for which there is usually no medical treatment, preventing its spread is important. Poor handwashing is the main cause of the spread of pink eye. Sharing an object, such as a face cloth or towel, with a person who has pink eye can spread the infection. For tips on how to prevent the spread of pink eye, see the Prevention section of this topic.

People with infectious pink eye should not go to school or daycare, or go to work until symptoms improve.

• If the pink eye is caused by a virus, the person can usually return to daycare, school, or work when symptoms begin to improve, typically in 3 to 5 days. Medicines are not usually used to treat viral pink eye, so it is important to prevent the spread of the infection. Pink eye caused by a herpes virus, which is rare, can be treated with an antiviral medicine. Home treatment of viral pink eye symptoms can help you feel more comfortable while the infection goes away.
• If the pink eye is caused by bacteria, the person can usually return to daycare, school, or work 24 hours after an antibiotic has been started if symptoms have improved. Prescription antibiotic treatment usually kills the bacteria that cause pink eye.

Pink eye may be more serious if you:

• Have a condition that decreases your body's ability to fight infection (impaired immune system).
• Have vision in only one eye.
• Wear contact lenses.

Red eye

Red eye is a more general term that includes not only pink eye but also many other problems that cause redness on or around the eye, not just the lining. Pink eye is the main cause of red eye. Red eye has other causes, including:

• Foreign bodies, such as metal or insects. For more information, go to the topic Objects in the Eye.
• Scrapes, sores, or injury to or infection of deeper parts of the eye (for example, uveitis, iritis, or keratitis). For more information, go to the topic Eye Injuries.
• Glaucoma. For more information, go to the topics Eye Problems, Non-injury or Glaucoma.
• Infection of the eye socket and areas around the eye. For more information, go to the topic Eye Problems, Non-injury.

Swollen, red eyelids may also be caused by styes, a lump called a chalazion, inflammation of the eyelid (blepharitis), or lack of tears (dry eyes). For more information, go to the topics Styes and Chalazia or Eyelid Problems (Blepharitis).

Use the Check Your Symptoms section to decide if and when you should see a doctor.