A sty is a red, painful lump near the edge of your eyelid that may look like a boil or a pimple. Sties are often filled with pus. A sty usually forms on the outside of your eyelid, but sometimes it can form on the inner part of your eyelid.
In most cases, a sty will begin to disappear on its own in a couple days. In the meantime, you may be able to relieve the pain or discomfort of a sty by applying a warm washcloth to your eyelid.
Another condition that causes inflammation of the eyelid is a chalazion. A chalazion occurs when there's a blockage in one of the small oil glands near the eyelashes. Unlike a sty, a chalazion usually isn't painful and tends to be most prominent on the inner side of the eyelid. Treatment for both conditions is similar.
Symptoms of sties and chalazions
Signs and symptoms of a sty or chalazion include:
A red lump on your eyelid that is similar to a boil or a pimple
Risk factors for sties and chalazions
You are at increased risk of a sty or chalazion if you:
Touch your eyes with unwashed hands
Insert your contact lenses without thoroughly disinfecting them or washing your hands first
Leave on eye makeup overnight
Use old or expired cosmetics
Have blepharitis, a chronic inflammation along the edge of the eyelid
Have rosacea, a skin condition characterized by facial redness
Prevention of sties and chalazions
To prevent eye infections:
Wash your hands.
Wash your hands with soap and warm water or use an alcohol-based hand sanitizer several times each day. Keep your hands away from your eyes.
Take care with cosmetics.
Reduce your risk of recurrent eye infections by throwing away old cosmetics. Don't share your cosmetics with others. Don't wear eye makeup overnight.
Make sure your contact lenses are clean.
If you wear contact lenses, wash your hands thoroughly before handling your contacts and follow your doctor's advice on disinfecting them.
Apply warm compresses.
If you've had a sty before, using a warm compress regularly may help prevent it from coming back.
If you have blepharitis, follow your doctor's instructions for caring for your eyes.