Overview

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.

Symptoms

Signs and symptoms of a sty include:

  • A red lump on your eyelid that is similar to a boil or a pimple
  • Eyelid pain
  • Eyelid swelling
  • Tearing

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 at the margin of the eyelid, just behind 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.

When to see a doctor

Most sties are harmless to your eye and won't affect your ability to see clearly. Try self-care measures first, such as applying a warm washcloth to your closed eyelid for 5 to 10 minutes several times a day and gently massaging the eyelid. Contact your doctor if:

  • The sty doesn't start to improve after 48 hours
  • Redness and swelling extend beyond your eyelid and involve your cheek or other parts of your face

Causes

A sty is caused by an infection of oil glands in the eyelid. The bacterium staphylococcus is responsible for most of these infections.

Risk factors

You are at increased risk of a sty 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

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 compress regularly may help prevent it from coming back.
  • Manage blepharitis. If you have blepharitis, follow your doctor's instructions for caring for your eyes.
June 03, 2015
References
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  3. What Are Chalazia and Styes? American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/diseases/chalazion-stye.cfm. Accessed March 31, 2015.
  4. What you need to know about contact lens hygiene and compliance. American Optometric Association. http://www.aoa.org/x8024.xml. Accessed March 31, 2015.
  5. Chalazion and hordeolum. Merck Manual Professional Edition.  http://www.merckmanuals.com/professional/eye-disorders/eyelid-and-lacrimal-disorders/chalazion-and-hordeolum-stye. Accessed March 31, 2015.
  6. Eye cosmetic safety. U.S. Food and Drug Administration. http://www.fda.gov/Cosmetics/ProductsIngredients/Products/ucm137241.htm. Accessed March 31, 2015.
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  8. Wash your hands. Centers for Disease Control and Prevention. http://www.cdc.gov/Features/HandWashing. Accessed April 1, 2015.
  9. Using eye makeup. American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/living/eye-makeup.cfm. Accessed April 1, 2015.
  10. Chalazion and stye treatment. American Academy of Ophthalmology. http://www.geteyesmart.org/eyesmart/diseases/chalazion-stye/treatment.cfm. Accessed April 1, 2015.
  11. Robertson DM (expert opinion). Mayo Clinic, Rochester, Minn. April 18, 2015.