Conjunctivitis - Diagnosing conjunctivitis

Your GP should be able to diagnose conjunctivitis by asking about your symptoms and examining your eyes.

It can be helpful to describe to your GP how your conjunctivitis started as this will help them diagnose which type it is and whether it needs to be treated.

The most common symptoms of infective conjunctivitis are sticky, red and watery eyes. However, infective conjunctivitis can sometimes be confused with other types of conjunctivitis, which are treated differently.

Swab test

Your GP may suggest further tests (such as a swab test) if your conjunctivitis hasn't responded to treatment or to help decide what treatment to use.

A swab looks similar to a small cotton bud. It's used to collect a small sample of mucus from your infected eye, which is sent to a laboratory to find out the cause of your conjunctivitis.

Find out more about treatments for infective conjunctivitis.

If your symptoms are severe or do not respond to treatment, you may need to see an eye specialist (ophthalmologist).

Other conditions

Most cases of conjunctivitis clear within one to two weeks, sometimes sooner, without needing any medical treatment. In some cases it can last for longer than two weeks, which is known as persistent infective conjunctivitis.

If you have any unusual symptoms such as severe pain, blurred vision or sensitivity to light, these may mean that you have a more serious condition.

If you have any of these symptoms, it is very important to seek medical assistance immediately, either by contacting your GP or visiting a hospital.

Other more serious conditions include:

Acute glaucoma: this rare form of glaucoma causes a painful build-up of pressure in your eye.
Keratitis: this is when your cornea (the clear layer at the front of your eye) becomes swollen and develops open sores.
Iritis: this is a type of uveitis (swelling of the middle layer of your eye) that causes pain, headaches and watery eyes.

Newborn babies

Contact your GP straight away if you think your baby may have infective conjunctivitis (also called neonatal conjunctivitis).

If this is not possible, call NHS 111 or your local out-of-hours service. Your GP will examine your baby closely to see if they have sticky eyes or infective conjunctivitis.

Any newborn baby with infective conjunctivitis must be referred to an eye specialist straight away for treatment.

Find out more about the symptoms of infective conjunctivitis.

Conjunctiva: The conjunctiva is the transparent membrane (thin layer of cells) that covers the white part of the eyeball and the inner surfaces of the eyelids.
Inflammation: Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.