What is a Sty?

Styes are localized skin infections occurring along the edge of the eyelids. Most styes begin with a blocked oil gland that traps bacteria under the skin. Styes are painful but not usually dangerous, while some complex and untreated growths may threaten the eye itself. A sty is not an emergency unless it’s accompanied by a high fever, obstructs your ability to see, or is bleeding or discharging.

What are the Symptoms of a Sty?

Most styes appear similar to pimples because they are related in many ways. As the bacteria grows under the skin and your body fights the infection to produce pus, the growth swells and usually develops a visible white head.

The swelling puts pressure on the sensitive skin around the eyelids, resulting in pain, tenderness, and even itchiness. The sty itself will likely appear bright red or pink. It may appear on the inside of the eyelid and only cause swelling and redness through the lid.

Sty Causes

Sties are caused by staphylococcal bacteria, which live on the surface of your skin. It’s no secret that our bodies host billions of “friendly” bacteria that live harmoniously with us. However, sometimes the conditions are perfect for the bacteria to begin feasting on dead cells and debris on the surface of your skin. The result is a tender pimple on the edge of your eyelid.

The tiny infectious lump could have been triggered when you touched something dusty, then rubbed your eye. No one yet knows what determines when sties will form. However, they’re usually caused by staphylococcus aureus, a staph bacteria.

A chalazion is often confused with a sty but is a different condition entirely. It’s caused when tiny eyelid gland ducts are blocked and can no longer transport an oily substance used to lubricate your eye. This oily material gets into the tear film and prevents evaporation, so the eye stays moist. When the backed up oil triggers an immune system response, a chalazia develops, usually over weeks or months.

How is a Sty Treated?

The pressure and pain is immediately reduced by draining the sty, but this should be done by a medical professional. It’s very easy to damage the eye or cause a more serious infection by trying to lance or pop a sty on your own.

A doctor will determine if the infection is severe enough to warrant antibiotics as well. Most styes go away within a few days without any treatment, but styes that last longer than a week deserve a professional’s opinion. Regular outbreaks of styes are usually easy to prevent by following hygiene practices like washing around the eyes at least once a day specifically to remove oils.

Sty Prevention

If you have a tendency to develop sties, maybe it’s time to take better care of your eyelids. Wash them thoroughly so that bacteria have nothing to feed on. To do this, simply put a tiny bit of baby shampoo into a cup of warm water and stir to mix it up. Take a cotton swab or washcloth to dip into the solution and wipe along the base of your eyelashes. Keep your eyes shut during the process.

Here are a few other strategies to prevent sties from forming:

  • refrain from rubbing your eyes, which irritates your skin and lets in bacteria.
  • whenever possible, protect your eyes from dirt and air pollution. For example, slip on safety glasses while completing dusty chores such as mowing your yard or raking leaves.
  • keep track of when you purchase makeup and discard any older than six months, especially eye makeup such as mascara. Old makeup can be crawling with bacteria.
  • be sure to treat any infection on your eyelid right away.
Last Reviewed:
October 11, 2016
Last Updated:
November 28, 2017