A stye is a sore and red lump near the edge of an eyelid. It is caused by an infection at the base of an eyelash (in the follicle). Staphylococcal bacteria are the usual culprits. These bacteria normally live harmlessly on the skin, but they can cause infection if the skin is damaged. Touching mucus from the nose and then rubbing the eye is one way of moving staphylococcal bacteria to the eyelid.

Styes may be red and sore, but they generally do not cause any damage to the eye or eyelids. Most clear up within a few days, even if no treatment is received. However, the infection from one stye can sometimes spread and cause more styes. Rarely, the entire eyelid may become infected. This requires medical treatment, including antibiotics. Some people seem to get many styes, while others get few or none at all.

The way a stye develops includes:

• A painful, red and tender lump develops on the eyelid.
• The lump gets larger and may develop a white or yellow top. This means there is pus in the stye, and is called 'pointing'. The point can be along the edge of the eyelid (where eyelashes grow), or it can be inside the eyelid. It is not usual for it to be on the outside of the eyelid.
• The stye can irritate the eye, causing it to water, and it can feel like there is something 'in the eye' (like when an eyelash gets onto the surface of the eye).
• The surface over the stye may break, releasing the pus, or the swelling may go away without bursting, when the body's immune system is able to control the infection.
• If the pus drains out of the stye, the lump goes away quite quickly. Otherwise, the swelling may take longer to go down.

You should see a doctor if you experience:

• a stye that is not getting better after a couple of days
• a stye that obstructs your vision
• red, swollen, painful skin around the stye
• other problems such as fever, eye discharge, nausea, headache, or loss of appetite

Antibiotics are not usually used to treat styes.

If a stye lasts longer than 3 months, a doctor may have to remove It.

See your doctor straight away or go to the nearest hospital emergency department if the skin on your eyelid or the eye itself becomes red, swollen or painful.

Styes usually clear up by themselves in a few days.

Styes usually grow larger and release pus before going away.

Here are some things you can do to help your stye heal:

• Hold a warm compress against your closed eyelid for 2 to 5 minutes at a time. This can help open the blockage. A clean face washer that has been wet with very warm water is ideal. Be careful not to burn yourself, but ensure the water is as warm as you can handle. Do this up to 20 times a day, gently massaging your eyelid. Always make sure your eye is closed when doing this.
• Keep the area around your eye clean by gently washing your eyelid with water.
• You can also clean your eyelid by using a damp cotton wool pad to wipe away any discharge. Do not use dry cotton wool or a tissue to clean your eyelid since this may scratch it.
• Try not to wear eye make-up or contact lenses until the stye has gone as this may irritate your eye and block the glands further.
• Try not to rub, poke, prod, squeeze or scratch the stye since this could cause the infection to spread. Avoid using sharp objects, such as tweezers, around your eyes.

Some cosmetic and hygiene choices increase your risk of getting a stye.

Ways to prevent styes include:

• Wash your hands thoroughly and avoid touching your eyes.
• Avoid using old cosmetics and sleeping in makeup.
• If you use contact lenses, make sure your hands are clean before you touch them. Ask your doctor or pharmacist how to disinfect your contacts.

Some skin conditions such as blepharitis and rosacea can also increase your risk of a stye. Ask your doctor for advice.