Sty Facts: What Causes a Sty?

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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Sty (stye) facts

  • A sty (sometimes spelled stye and medically referred to as a hordeolum) is a tender, painful red bump located at the base of an eyelash or under or inside the eyelid.
  • Application of a warm compress or warm washcloth to the affected area for 10 minutes, four to six times a day, can speed drainage of the sty and aid in the relief of symptoms.
  • Styes are common and are generally harmless.
  • A chalazion (a form of scarring of the glands in the eyelid that may include the formation of cysts) is the most common complication that develops from a sty.

What is a sty?

A sty (sometimes spelled stye) is a tender, painful red bump located at the base of an eyelash or under or inside the eyelid. A sty results from a localized infection of the glands or a hair follicle of the eyelid. The medical term for a sty is hordeolum (plural, hordeola).

The term external hordeolum refers to a sty that develops at the base of an eyelash (the hair follicle), whereas the term internal hordeolum refers to a sty that develops in a meibomian gland, a gland located on the underside of the eyelid that secretes an oily substance onto the eyeball.

A sty is sometimes confused with a chalazion (see below), which is a cyst or a specific type of scarring due to chronic inflammation arising in the meibomian glands of the eyelid. A chalazion may develop when the infection of a sty persists over time, resulting in scarring around the meibomian gland. In contrast to a sty, a chalazion is usually painless.

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What is the cause of a sty?

A sty results from an infection of the oil glands of the eyelid (meibomian glands) that help to lubricate the eyeball. The infection occurs after these glands have become clogged. A sty also may arise from an infected hair follicle at the base of an eyelash. The bacterium Staphylococcus aureus that is frequently found on the skin is responsible for 90%-95% of cases of styes. A sty also can develop as a complication of diffuse inflammation of the eyelid (blepharitis).

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Medically reviewed by William Baer, MD; Board Certified Ophthalmology

REFERENCE:

Bessette, Michael J. "Hordeolum and Stye in Emergency Medicine." Medscape.com. Feb. 24, 2010. <http://emedicine.medscape.com/article/798940-overview>.


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Reviewed on 5/13/2016

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