People get styes when an oil gland or eyelash follicle on the eyelid gets clogged and infected, most often by staph bacteria. Common triggers include touching your eyes with unwashed hands, wearing old eye makeup, poor contact lens hygiene, blepharitis, and rosacea.

What a stye is

A stye is a painful, red bump near the eyelash line that can look like a pimple or boil. It usually forms when a gland at the edge of the eyelid becomes inflamed or infected.

Common causes

  • Bacteria entering a clogged eyelid oil gland.
  • Touching or rubbing the eyes with dirty hands.
  • Leaving eye makeup on overnight or using old cosmetics.
  • Not disinfecting contact lenses properly.
  • Ongoing eyelid inflammation such as blepharitis.
  • Skin conditions like rosacea.

Why some people get them more

Some people are more prone to styes because their eyelid glands get blocked more easily or because they have chronic eyelid irritation. Recurrent styes are often linked to blepharitis or rosacea rather than a one-time accident.

When to get checked

A stye usually improves on its own, but you should get medical advice if it keeps coming back, gets worse, or starts affecting your vision.

TL;DR: styes are usually caused by a blocked eyelid gland that gets infected, often from everyday bacteria plus things like eye rubbing, makeup, or contact lenses.