A stye is a small, painful bump on the eyelid caused by a bacterial infection in one of the tiny oil glands or hair follicles along your lash line. The bacterium responsible is almost always Staphylococcus aureus, a common skin bacterium that causes trouble when it gets trapped in a blocked gland. Styes typically last one to two weeks and resolve on their own, but understanding what triggers them can help you avoid getting one in the first place.
How a Stye Forms
Your eyelids contain dozens of small oil-producing glands that keep your tears from evaporating too quickly. When one of these glands gets clogged, the oil inside thickens and can’t drain. That stagnant oil becomes a breeding ground for bacteria, which multiply and trigger an immune response. The result is a red, swollen, tender bump that looks a bit like a pimple.
There are two types. External styes, which are far more common, develop at the base of an eyelash where it meets the tiny oil glands along the lid margin. Internal styes form deeper inside the eyelid, in the larger oil glands (called meibomian glands) embedded in the lid itself. Internal styes tend to be more painful because they press against the eye, but both types follow the same basic pattern of blockage, bacterial overgrowth, and inflammation.
What Increases Your Risk
Anything that clogs your eyelid glands or introduces bacteria to the area raises your chances of developing a stye. The most common risk factors are everyday habits you may not think twice about.
- Touching your eyes with unwashed hands. This is the single most direct way to transfer staph bacteria to your eyelid glands.
- Old or shared eye makeup. Mascara should be replaced every six months. Liquid eyeliner lasts about six months as well, while pencil liners can go one to two years. Moisture in liquid products helps bacteria and mold grow faster, especially in warm, humid conditions.
- Sleeping in contact lenses or handling them with dirty fingers. Both habits introduce bacteria and irritate the lid margin.
- Chronic eyelid inflammation (blepharitis). This ongoing low-grade irritation along the lash line thickens oil secretions and makes blockages more likely. Blepharitis is one of the most frequently identified links to recurrent styes.
- Rosacea. People who had styes as children are significantly more likely to develop rosacea as adults. A study using the Rochester Epidemiology Project found that childhood stye patients had a rosacea prevalence of 5.5%, compared to 1.5% in control subjects. The connection runs both directions: rosacea-related skin inflammation can also promote stye formation.
- Meibomian gland dysfunction. When the larger oil glands in your eyelids chronically under-produce or produce poor-quality oil, blockages become routine. Left untreated, this condition can lead to repeated styes.
What a Stye Feels Like
Most styes announce themselves with tenderness and slight swelling at the edge of the eyelid before a visible bump appears. Over the next day or two, a defined, pea-sized lump forms right at the lid margin. It may feel warm to the touch, and your eye might water more than usual. Some people notice their whole eyelid swells, even though the infection is localized to one small gland.
Internal styes are harder to spot because the bump faces inward, toward the eyeball. You may feel like something is pressing against your eye when you blink. If you gently flip your eyelid, you can sometimes see a small yellowish spot on the inner surface.
Styes vs. Chalazions
A chalazion looks similar to a stye but develops differently. While a stye is an active bacterial infection that appears quickly and hurts, a chalazion is a slowly growing, painless lump that forms when a blocked gland becomes chronically inflamed without significant infection. Location offers a clue: styes sit right at the lid margin near the lashes, while chalazions typically appear in the middle portion of the eyelid, set back from the edge.
Styes sometimes turn into chalazions. Once the acute infection clears, the blocked gland can remain swollen and firm for weeks or months. A chalazion that doesn’t resolve on its own may need a minor in-office drainage procedure.
How to Treat a Stye at Home
Warm compresses are the most effective home treatment. Soak a clean cloth in warm water, wring it out, and hold it against your closed eyelid for 5 to 10 minutes, repeating 3 to 6 times per day. The heat softens the hardened oil inside the blocked gland, helping it drain naturally. Most styes will start to improve within a few days of consistent compress use.
Resist the urge to squeeze or pop a stye. Forcing it open can spread the infection into surrounding tissue. Let it drain on its own, and gently clean away any discharge with a damp cloth. While the stye is active, skip eye makeup and contact lenses to avoid reintroducing bacteria or trapping more debris against the inflamed area.
When a Stye Needs Medical Attention
Most styes are harmless and self-limiting, but a small number progress to more serious infections. If the pain and swelling haven’t started improving after 48 hours of warm compresses, that’s a reasonable point to get it checked. Other signs that warrant a visit include your eyelid swelling shut, pus or blood leaking from the bump, blisters forming on the lid, your eyelid feeling hot, or any changes to your vision.
The concern with a worsening stye is that the infection can spread beyond the gland into the surrounding soft tissue of the eyelid, a condition called preseptal cellulitis. This causes diffuse swelling across the lid rather than a contained bump. In rare cases, infection can spread deeper into the eye socket, which produces pain with eye movement and vision changes. These are distinct warning signs that separate a routine stye from something that needs prompt treatment.
Styes that keep coming back often point to an underlying condition like blepharitis or meibomian gland dysfunction. Addressing the root cause, usually through a daily lid hygiene routine that keeps the oil glands clear, is more effective than treating each stye individually.
Preventing Styes
A few simple habits make a real difference. Wash your hands before touching your face or handling contact lenses. Replace liquid eye cosmetics every six months, and never share mascara or eyeliner. If you’re prone to styes, a nightly lid-cleaning routine helps: use a warm washcloth or a commercially available lid scrub to gently clean along your lash line, loosening any oil or debris before it has a chance to harden inside a gland.
If you have blepharitis or rosacea, managing those conditions consistently reduces stye frequency. Keeping your meibomian glands functional through regular warm compresses, even when you don’t have an active stye, prevents the oil stagnation that starts the whole process.