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20 June 2011

Conjunctivitis (pink eye)

Conjunctivitis is an inflammation of the conjunctiva, which is a thin, transparent membrane that covers the surface of the inner eyelid and the front of the eye.

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Summary

  • Conjunctivitis (also known as pink eye) is an inflammation of the conjunctiva, a membrane covering the inner eyelid and front of the eye.
  • Conjunctivitis can be infectious or non-infectious.
  • Infectious conjunctivitis is contagious.
  • Infectious conjunctivitis can be caused by bacteria or viruses or other microorganisms.
  • Non-infectious conjunctivitis can be caused by allergy, chemical irritation, underlying inflammatory diseases, or trauma.

Definition 

Conjunctivitis is an inflammation of the conjunctiva, which is a thin, transparent membrane that covers the surface of the inner eyelid and the front of the eye. This membrane reacts to a wide range of bacteria, viruses, allergy-provoking agents, irritants and toxic agents, as well as to underlying diseases within the body. The conjunctiva is usually clear, but if irritation or infection occurs, the lining becomes red and swollen.

The common name for conjunctivitis is "pink eye". Pink eye is very common, usually not serious, and often resolves in a few days without medical treatment.

The main types of conjunctivitis are infectious and allergic.

Neonatal conjunctivitis occurs in a newborn child. One of the most common causes is sexually transmitted diseases such as Chlamydia, which are acquired by the baby as it is born. This needs to be treated with antibiotics and the mother and partner will also need treatment.

  • Infectious conjunctivitis is usually caused by a contagious virus or bacteria (but may occasionally be caused by a fungus or other organism).
  • "Pink eye" refers to any kind of conjunctivitis. However, especially in schools, "pink eye" refers to a particular viral conjunctivitis (caused by the adenovirus) that is very contagious. Occasionally this form of pink eye can be associated with infection of the cornea (the clear portion of the front of the eyeball).
  • Other viruses, such as those causing herpes simplex, chicken pox, shingles, or measles, can also infect the conjunctiva.
  • Blepharitis is inflammation and infection of the eyelids, usually marked by redness and crusting at the margins along the lash line. This can cause a secondary bacterial conjunctivitis. Other problems with the eyelids that can lead to or exacerbate conjunctival irritation are styes, a lump called a chalazion, or tear deficiency.
  • A raised, yellowish growth on the wall of the eye called a pingueculum can often become inflamed by exposure to irritating environments, such as a dry, windy climate.
  • Allergies to pollen, cosmetics, animals or fabrics often bring on allergic conjunctivitis.
  • Chemical pink eye can result when any irritating substance enters the eyes. Common irritants are household cleaners, sprays, smoke, smog, industrial pollutants and chlorine in swimming pools.
  • Conjunctivitis may be drug-induced. Reactions can occur to preservatives in eye drops, or after prolonged use of topical antibiotics or antivirals.
  • Conjunctivitis is a well-known complication of wearing contact lenses.

Mimicking disorders

  • Uncommon underlying illnesses can cause redness of the eye, mimicking conjunctivitis. Most often these are rheumatic diseases, such as rheumatoid arthritis and certain inflammatory bowel diseases.
  • Subconjunctival haemorrhage, or "eye bruise", occurs when a portion of the wall of the eye (white of the eye) suddenly becomes bright red. This occurs when the tiny blood vessels covering the whites of the eyes rupture from trauma or changes in pressure within the head (for example, as a result of forceful laughing, coughing, sneezing or vomiting, diving under water, or even bending upside down). This tends to be asymptomatic and is usually pointed out by another person. It can appear quite alarming, but is in fact a harmless haemorrhage or bruise under the conjunctiva.
  • The wall of the eye beneath the conjunctiva can become inflamed (episcleritis or scleritis). These conditions often involve only one eye. They are generally not infectious processes, and sometimes are associated with various medical conditions. They are potentially serious and need to be evaluated by an ophthalmologist and usually treated with anti-inflammatory medications.
  • Acute glaucoma (raised pressure within the eye) can cause a red eye.
  • Foreign bodies, scrapes and sores on the cornea can cause a red eye.

Symptoms

Common symptoms of pink eye are:

  • Red, watery eyes
  • Eye pain
  • Swollen eyelids
  • A sandy or scratchy feeling in the eyes, itching or burning
  • Mild sensitivity to light
  • Drainage from the eye – pus-like or watery discharge around the eyelids may indicate an infectious form of the disease. Discharge as a result of bacterial infection may be thick or crusty, and is usually yellow or greenish. The discharge commonly accumulates during sleep, often sticking the eyelids together and making it difficult to open the eyes on waking. Viral conjunctivitis is usually associated with a more watery discharge that is not green or yellow, and is frequently associated with viral "cold-like" symptoms.
  • Blurred vision

Prevalence

Conjunctivitis is a common condition. It affects people of all ages, and is common in childhood. Allergic conjunctivitis is frequently seasonal, and goes along with other typical "allergy" symptoms such as sneezing, itchy nose, or scratchy throat.

Treatment

Home

Home treatment will help reduce the pain of conjunctivitis and keep your eye free of drainage.

  • If you wear contact lenses, remove them and wear glasses until your symptoms have cleared up.
  • Cool or warm compresses can be used, whichever feels better. If an allergy is the problem, a cool compress may be more soothing. With infectious pink eye, a warm, moist compress may help reduce redness and swelling. Use a different compress for each eye, and a clean compress for each application of warmth, to prevent spreading the infection.
  • Clean the eyelid margins and eyelashes gently and repeatedly with a warm, moist cloth or cotton ball. Wipe from the inside, next to the nose, towards the outside of the eye. Use a clean surface for each wipe so drainage being cleaned away is not rubbed back across the eye. Throw used wipes away. After wiping your eye, wash your hands to prevent drainage from spreading the condition.
  • If a chemical substance has gone into the eye, wash the eye out immediately and copiously with water or any non-irritant fluid and phone a doctor as soon as possible for advice. Certain forms of conjunctivitis can develop into a serious condition that may harm your vision. It is therefore important to have conjunctivitis diagnosed and treated quickly.
  • The ideal treatment for allergic and chemical conjunctivitis is to remove the cause of the allergy or irritation. For instance, avoid contact with animals or other environmental factors that cause an allergic reaction. Wear swimming goggles if chlorinated water irritates the eyes. In cases where these measures won’t work, prescription and over-the-counter eye drops are available to help relieve the discomfort.

Pink eye may be more serious if any one of the following applies:

  • Only one eye is affected.
  • Your vision is affected.
  • It is very painful.
  • It does not settle within three days.
  • You wear contact lenses.

A doctor should evaluate conjunctivitis in an infant or toddler because additional treatments such as systemic antibiotics may be necessary.

Medication

Infectious conjunctivitis caused by bacteria is usually treated with antibiotic eye drops or ointment and usually responds within a few days. Some kinds of bacterial conjunctivitis need to be treated with oral antibiotics as well as eye drops or ointments. Be careful not to use medication prescribed for someone else, or for an old infection, as these may be inappropriate for the current infection or may have been contaminated by previous infections.

Viruses in general do not respond to antibiotics – the infection tends to run its course and resolve by being fought off by your body’s immune system. Some antibiotics may be prescribed, however, to prevent secondary bacterial infections from developing. It is sometimes difficult to distinguish between bacterial and viral conjunctivitis.

To apply eye drops or ointment

  • For older children and adults, pull the lower eyelid down with two fingers to form a small pouch. Put the drops or ointment there. Close the eye for a minute to prevent the medication running out of the eye.
  • Ask younger children to lie down with eyes closed. For eye drops, put a drop in the inner corner of the eye. When the eye opens, the drop will run in. For ointment, pull the lower eyelid down to form a pouch in which to put the ointment. Ask the child to close his or her eyes and move the eyeball from side to side to move the drops or ointment around the eye.

In the case of allergic conjunctivitis topical antihistamines may be prescribed. In severe cases short-term topical steroids may be considered.

Prevention

Viral and bacterial conjunctivitis are contagious and spread very easily. Poor hand washing is the main cause of the spread of viral conjunctivitis. Sharing an object with a person who has conjunctivitis can spread the infection. Conjunctivitis is spread through contact with the eye discharge, which contains the virus or bacteria.

To prevent infectious conjunctivitis:

  • Do not share eye make-up.
  • Do not share contact lens equipment, containers or solutions.
  • Do not share towels, linens, pillows or handkerchiefs.
  • Wear safety glasses when working with chemicals.

To prevent the spread of pink eye:

  • Keep your hands away from your eyes.
  • Wash your hands before and after touching the eyes or face, or using medicine in your eyes.
  • Change linen, towels and washcloths daily, and do not share these items.
  • Do not share eye make-up, contact lens equipment or eye medication.
  • If your eye infection was caused by a bacteria or virus, throw away your old make-up and buy new products.
  • Do not use eye make-up until the infection is fully cured, or you could re-infect yourself with the eye make-up products.
  • Do not wear contact lenses until the infection is cured. Thoroughly clean your contact lenses before wearing them again.
  • Do not attend day-care, school, go to work or use public swimming pools until symptoms of viral conjunctivitis have begun to improve, which should be within three to five days. Since there are no medications to treat viral conjunctivitis, it is important to prevent the spread of the infection. Home treatment of the symptoms only helps you feel more comfortable while the infection clears up.
  • Do not attend day-care, school, or go to work until bacterial conjunctivitis has been treated for 24 hours with an antibiotic, which usually kills the bacteria.
  • If eye drops or ointment is prescribed, be sure the dropper is clean and does not touch the eye, eyelid or any surface. Replace the dropper or bottle if their tips touch the eye or surrounding area.
  • Seek treatment promptly.

Previously reviewed by Dr L.C. Boezaart, M.B.Ch.B, M.Prax.Med, M.Med (Ophth)

Reviewed by Dr Clive Novis, Ophthalmologist, June 2011

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