A stye is caused by a blockage of one of the oil glands in the eyelids. This allows bacteria to grow inside the blocked gland. Styes are a lot like common acne pimples that occur elsewhere on the skin. You may have more than one stye at the same time.

Styes most often develop over a few days. They may drain and heal on their own. A stye can become a chalazion, which occurs when an inflamed oil gland becomes fully blocked. If a chalazion gets large enough, it can cause trouble with your vision.Styes can be made worse by the presence of Demodex, a mite commonly found on human skin. Demodex has been identified as a cause of blepharitis.

If you have blepharitis, you are more likely to get styes.Other possible common eyelid bumps include:SymptomsIn addition to the red, swollen bump, other possible symptoms of a stye include:Tenderness of the eyelid,A gritty, scratchy sensation, as if there is a foreign body in your eye,,Sensitivity to light,

Tearing of your eye.Treatment and diagnosisYour eye doctor can usually diagnose a hordeolum or chalazion on sight. Most of the time, neither condition requires medical treatment.

Both tend to clear up on their own, and styes are so short-lived that the infection may already be healing or gone by the time your appointment rolls around. However, it never hurts to contact your eye doctor at the first signs. Depending on your diagnosis, they may prescribe an ointment or other prescription medication to help it heal faster. Plus, they will be able to diagnose and treat any underlying causes, such as meibomian gland disease.