A stye is a small, painful bump on the eyelid caused by a bacterial infection in one of the tiny oil or sweat glands along the lash line. It looks similar to a pimple, usually fills with pus, and tends to resolve on its own within one to two weeks. Styes are one of the most common eyelid problems, and while they’re uncomfortable and sometimes alarming to look at, they’re rarely dangerous.
External vs. Internal Styes
Not all styes form in the same spot. An external stye develops right at the edge of the eyelid, in the small oil or sweat glands that sit at the base of your eyelashes. These are the ones you can usually see and feel as a tender, red bump on the lid margin. They tend to come to a head much like a pimple on your skin.
An internal stye forms deeper inside the eyelid, in the larger oil glands embedded within the eyelid’s firm inner structure. Because these glands sit farther from the surface, internal styes may cause more generalized swelling and can be harder to see directly. They also tend to be more painful, since the swelling pushes against the firm tissue of the eyelid rather than bulging outward.
What Causes a Stye
The culprit is almost always Staphylococcus aureus, a bacterium that commonly lives on skin without causing problems. A stye forms when this bacteria gets into a gland opening along the eyelid and triggers an infection. The gland swells, fills with pus, and becomes inflamed.
Anything that blocks or irritates those glands raises the risk. Touching or rubbing your eyes with unwashed hands is one of the most common ways bacteria get introduced. Old or contaminated eye makeup is another frequent cause. Beyond everyday habits, certain chronic conditions make styes more likely to recur. Blepharitis, a persistent low-grade inflammation of the eyelid margins, keeps the glands irritated and prone to blockage. Ocular rosacea has a similar effect: it inflames the oil glands in the eyelids and disrupts their normal function, creating conditions where infections take hold more easily. People with these conditions often deal with repeated styes rather than a single episode.
Styes can happen at any age, but data from a large Japanese study found that cases requiring medical treatment peaked in two age groups: children and young teens (ages 10 to 14) and adults in their 30s. Young women in their late teens and early 20s were slightly more likely to need treatment than males of the same age, possibly reflecting differences in makeup use or hormonal influences on oil gland function.
Stye vs. Chalazion
People often confuse styes with chalazions because both are bumps on the eyelid, but they feel quite different. A stye is an active infection: it’s very painful, red, and tender, and it typically sits right at the eyelid’s edge near the lashes. A chalazion is not usually painful. It develops farther back on the eyelid, away from the lash line, and is caused by a blocked oil gland without active infection. Think of it as a clogged gland that has hardened into a firm, slow-growing lump.
Sometimes a stye that doesn’t fully drain evolves into a chalazion. If a painless bump lingers on your eyelid for weeks after a stye has calmed down, that’s likely what’s happened.
How to Treat a Stye at Home
Warm compresses are the cornerstone of stye treatment. Soak a clean washcloth in warm water, wring it out, and hold it against the closed eyelid for 5 to 10 minutes. Repeat this 3 to 6 times a day. The heat softens the clogged material inside the gland, encourages drainage, and increases blood flow to help your body fight the infection. 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 and make things significantly worse. Let it drain on its own. You can gently clean the eyelid with a mild, diluted baby shampoo or a pre-moistened eyelid wipe to keep the area clear of crusting and debris.
If the pain and swelling haven’t started improving after 48 hours of home care, or if they’re actively getting worse after two to three days, it’s time for a professional evaluation. An eye doctor can determine whether you need a prescription antibiotic or, in stubborn cases, a minor in-office procedure to drain the stye.
Signs of a More Serious Problem
A straightforward stye stays confined to a small area of the eyelid. Watch for signs that the infection is spreading beyond the bump itself. Redness and swelling that extend across the entire eyelid or onto the skin around the eye can signal periorbital cellulitis, a skin infection that needs prompt antibiotic treatment. A fever, increasing eye pain, changes in vision, or any bulging of the eye are reasons to seek care quickly. These symptoms suggest the infection may be moving into deeper tissues around the eye socket, which is a more serious situation that requires urgent medical attention.
Preventing Styes
Since bacteria on your hands and in old cosmetics are the most common triggers, a few practical habits go a long way. Always wash your hands before touching your eyes or applying makeup. Never share eye cosmetics with others.
Pay attention to how long you keep your products. Replace mascara every three months, eyeliner every six months, and eyeshadows at least once a year. Bacteria accumulate in these products over time, and mascara wands in particular create a warm, moist environment where staph thrives. Wash your makeup brushes with gentle soap and warm water at least once a week, and let them dry completely before using them again.
How you apply makeup matters too. Avoid lining the inner rim of your eyelid (the waterline) with eyeliner, as this can directly block the oil gland openings. Remove all eye makeup thoroughly before bed using an oil-free remover or micellar water, followed by a gentle face wash. Sleeping in makeup leaves residue sitting on gland openings for hours.
If you deal with recurring styes, talk to an eye care provider about whether you have an underlying condition like blepharitis or meibomian gland dysfunction. Treating that chronic inflammation with a daily eyelid hygiene routine can break the cycle of repeated infections.