Acute conjunctivitis is redness and soreness (inflammation) of the clear covering (the conjunctiva) that coats the white of the eye and lines the inside of the eye lids. This comes on relatively quickly and lasts for a fairly short time. Acute conjunctivitis may clear on its own, but often needs treatment from your doctor.

• Mostly both eyes are affected, but often one starts before the other.
• The eye is red, with the blood vessels over the white of the eye more visible and swollen. The lining of the eyelids also looks redder or pinker than usual.
• The eye is sticky, with a discharge, which is worse when you wake up.
• The eye is itchy or painful.
• Sometimes people do not like to be in bright light (photophobia).

• The commonest cause is infection with bacteria.
• Virus infection may also occur.
• Allergic reactions, for example hay fever, may cause conjunctivitis, but do not usually cause a sticky discharge.

Your doctor will want to rule out more serious problems, which might affect the vision, and may examine you with a special flashlight for looking into and at the eye (an ophthalmoscope). In some circumstances, if there is doubt about the diagnosis, your doctor might use special fluorescent eye drops to examine the eye better.

Sometimes, especially if the treatment is slow to work, your doctor may take a specimen of the germs in the eye on a small swab (like a cotton bud) and send it to the laboratory for analysis.

It helps to bathe the eyes with water or water with a pinch of salt in it. Beware, conjunctivitis is often very contagious. Wash your hands after touching your eyes (or your child's eyes, if you are nursing them), as it is very easy to infect others by spreading the germs on your fingers or on tissues etc.

Over the counter eye cleansing solution can also soothe the eyes, but in the presence of a bacterial infection you will probably need antibiotic drops or ointment. The pharmacist may be able to provide these, but otherwise, or if treatment is not working, you should see your doctor. In some rare infections, antibiotics are also given by mouth.

Your doctor may prescribe drops or ointment, or both. Drops stay in the eyes for a shorter time, but ointment tends to blur the vision. Sometimes your doctor may prescribe drops by day with ointment at night.

If the problem is a virus infection, then it will not respond to antibiotics and your body will have to fight off the infection.

If your doctor thinks that the problem is allergic, then you may be prescribed antihistamines, cromolyn sodium eye drops, or nedocromil eye drops.

You are more prone to conjunctivitis after a cold, but anyone can pick it up. Certainly it is important to avoid spreading the germs, and anyone with conjunctivitis, and those treating them, should be scrupulous about washing their hands after touching the eyes, and disposing of tissues straight into the bin.