A stye forms when one of the tiny oil or sweat glands along your eyelid gets blocked and then infected, almost always by a common skin bacterium called Staphylococcus aureus. That bacterium already lives on your skin and lashes. When it gets trapped inside a clogged gland, it multiplies and creates a small, painful abscess filled with white blood cells and debris. The result is that familiar red, swollen bump at the edge of your eyelid.
What Happens Inside the Eyelid
Your eyelids contain dozens of small glands that produce oils and moisture to keep your eyes lubricated. When one of these glands gets plugged, its secretions thicken and stagnate instead of flowing freely onto the surface of your eye. That stagnant oil becomes a breeding ground for bacteria, and the surrounding tissue swells in response to the infection.
There are two types of styes depending on which gland is involved. External styes, the more common kind, start in the oil or sweat glands right at the base of your eyelashes. They look like a pimple on the outer edge of your lid. Internal styes develop deeper inside the eyelid, in the larger oil glands embedded in the lid’s firm tissue. Internal styes tend to be more painful because the swelling presses against the eyeball, and they drain inward toward the inner surface of the lid rather than outward.
Why Styes Happen: Common Triggers
Anything that introduces bacteria to your eyelid or clogs those tiny glands raises your risk. The most common triggers are everyday habits you might not think twice about:
- Touching your eyes with unwashed hands. This is the single easiest way to transfer staph bacteria directly to your lash line.
- Sleeping in your makeup. Makeup that isn’t removed overnight builds up along the lash line, clogging gland openings and encouraging bacterial growth.
- Using old or expired cosmetics. Eye makeup should be replaced every three to six months. Beyond that, bacteria accumulate in the product and on applicators.
- Poor contact lens hygiene. Handling lenses with dirty hands or not cleaning them properly can carry bacteria straight to the eyelid.
- Sharing eye makeup. Brushes, mascara wands, and eyeliner pencils transfer bacteria between people.
None of these habits guarantee you’ll get a stye, but they shift the odds. Some people are simply more prone than others, and that often comes down to underlying conditions.
Chronic Conditions That Make Styes Recurrent
If you keep getting styes, the problem may not be a single dirty mascara wand. Two chronic conditions are closely linked to recurrent styes.
Blepharitis is a persistent, low-grade inflammation of the eyelid margins. It causes the oil glands to produce thicker, stickier secretions that are more likely to clog. Many people with blepharitis have a cycle of styes that only breaks when the underlying inflammation is managed with daily lid hygiene.
Ocular rosacea is an eye-related form of rosacea, the skin condition that causes facial redness and flushing. It produces burning, itching, and redness of the eyes, and one of its hallmark features is recurrent eyelid infections, including styes. The connection is the same: blocked glands in the eyelids. If you notice facial flushing, visible blood vessels on your cheeks, or chronic eye irritation alongside repeat styes, rosacea could be the root cause.
Stye vs. Chalazion
Not every bump on your eyelid is a stye. A chalazion looks similar but behaves differently. A stye is an active infection. It’s red, swollen, and very painful, and it usually sits right at the eyelid’s edge near the lash line. A chalazion, by contrast, is typically painless. It forms when a blocked gland becomes inflamed but not infected, and it tends to develop farther back on the lid, away from the lash line. Chalazia grow more slowly and can linger for weeks or months. A stye can sometimes turn into a chalazion once the initial infection clears but the gland remains blocked.
How Long a Stye Lasts
Most styes resolve on their own within one to two weeks. They typically come to a head, drain, and then shrink. The most effective home treatment is a warm, moist compress applied to the closed eyelid for 5 to 10 minutes, three to six times a day. The heat softens the hardened oil plugging the gland and encourages it to drain naturally. Use a clean washcloth soaked in warm (not hot) water. Don’t heat a wet cloth in the microwave, as it can get hot enough to burn the thin skin of your eyelid.
While it’s healing, keep the area clean with mild soap and warm water twice a day. Resist the urge to squeeze or pop the stye. Forcing it can push the infection deeper into the tissue or spread bacteria to neighboring glands.
When a Stye Needs Medical Attention
A stye that doesn’t improve after several weeks of warm compresses may need to be drained by an eye specialist in a sterile setting. This is a brief in-office procedure and is more common with chalazia that persist beyond one to two months.
Rarely, a stye can progress to a more serious infection called preseptal cellulitis, where the infection spreads into the surrounding eyelid tissue. Warning signs include a fever, increasing pain and swelling that extends beyond the bump itself, vision changes, or a bulging appearance of the eye. These symptoms call for immediate medical care, especially in children, because the infection can spread deeper into the eye socket if left untreated.
Reducing Your Risk
Preventing styes comes down to keeping bacteria and blockages away from your eyelid glands. Wash your hands before touching your face or handling contact lenses. Remove all eye makeup every night with a gentle remover, and toss mascara, eyeliner, and eyeshadow every three to six months. Never share eye cosmetics. If you wear contacts, follow your cleaning routine carefully and replace your lens case regularly.
For people with blepharitis or rosacea, a daily lid-cleaning routine can make a real difference. Warm compresses followed by a gentle scrub of the lash line help keep the oil glands from clogging in the first place, breaking the cycle before the next stye has a chance to form.