Most bumps on the eyelid are styes. A stye is an inflamed oil gland on the edge of your eyelid, where the lash meets the lid. It appears as a red, swollen bump that looks like a pimple. It is tender, especially to the touch.

A stye is caused by bacteria from the skin that get into the oil glands in the eyelids that provide lubrication to the tear film. Styes are similar to common acne pimples that occur elsewhere on the skin. You may have more than one stye at the same time.

Styes usually develop over a few days and may drain and heal on their own. A stye can become a chalazion -- this is when an inflamed oil gland becomes fully blocked. If a chalazion gets large enough, it can cause trouble with your vision.

If you have blepharitis (see eye redness), you are more likely to get styes.

Other possible eyelid bumps include:

• Xanthelasma -- raised yellow patches on your eyelids that can happen with age. These are harmless, although they are occasionally a sign of high cholesterol.
• Papillomas -- pink or skin-colored bumps. They are harmless, but can slowly grow, affect your vision, or bother you for cosmetic reasons. If so, they can be surgically removed.
• Cysts -- small fluid-filled sacs that can affect your vision.

In addition to the red, swollen bump, other possible symptoms include:

• Tearing of your eye
• A gritty, scratchy sensation as if there is a foreign body
• Sensitivity to light
• Tenderness of the eyelid

A doctor can diagnose a stye just by looking at it. Special tests are usually not necessary.

• Styes and chalazions can be treated by applying warm compresses. Apply for 10 minutes. Do this four times a day.
• Do NOT attempt to squeeze a stye or any other type of eyelid bump. Let it drain on its own.
• Antibiotic creams may help recurrent or persistent styes. Some large styes need to be lanced to drain the infection.

Styes often get better on their own. However, they may recur. The outcome is generally excellent with simple treatment.

• Recurrence of a stye
• Spread of infection to other eyelash follicles
• Spread of infection to the tissue of the eyelid (eyelid cellulitis)

Call your doctor if:

• You have problems with your vision.
• The eyelid bump worsens or does not improve within a week or two of self-care.
• The eyelid bump or bumps become very large or painful.
• You have a blister on your eyelid.
• You have crusting or scaling of your eyelids.
• Your whole eyelid is red, or the eye itself is red.
• You are very sensitive to light or have excessive tears.
• A stye comes back soon after successful treatment of another one.
• Your eyelid bump bleeds.

Always wash your hands thoroughly before touching the skin around your eye. If you are susceptible to styes, it may help to carefully clean off excess oils from the edges of your lids.

Pasternak A, Irish B. Opthalmologic infections in primary care. Clin Fam Pract. 2004; 6(1):19.

Noble J. Textbook of Primary Care Medicine. 3^rd ed. St. Louis, Mo: Mosby; 2001.