Eye styes are caused by bacterial infection of the oil glands in your eyelid, almost always by Staphylococcus aureus, a common skin bacterium. The infection starts when one of these tiny glands gets clogged, trapping oily secretions inside and creating the perfect environment for bacteria to multiply. While styes can happen to anyone, certain habits, health conditions, and skin issues make some adults far more prone than others.
How a Stye Forms
Your eyelids contain dozens of small glands that produce oils to keep your eyes lubricated and your tears from evaporating too quickly. When one of these glands gets blocked, its secretions stagnate. Bacteria that normally live harmlessly on your skin surface then colonize the trapped material, triggering an inflammatory response: redness, swelling, tenderness, and eventually a visible bump.
There are two types, depending on which gland is involved. An external stye affects the smaller oil or sweat glands (called the glands of Zeis or Moll) near the base of your eyelashes. These tend to form right along the lash line and may drain pus from the outer surface of the lid. An internal stye affects the larger meibomian glands deeper inside the eyelid. These are less visible from the outside and drain toward the inner surface of the lid, against the eye itself. Internal styes tend to be more painful because the swelling presses against the eyeball.
Everyday Habits That Raise Your Risk
The most common behavioral trigger is touching or rubbing your eyes with unwashed hands. This transfers staph bacteria directly to the eyelid margin, where they can enter a gland opening. If you rub your eyes frequently, whether from allergies, dryness, or habit, you’re introducing bacteria repeatedly throughout the day.
Old or shared makeup is another significant risk factor. Mascara, eyeliner, and eyeshadow applicators that sit in warm bathroom drawers become breeding grounds for bacteria over time. Liquid and cream products are especially hospitable. Replacing eye makeup every three to six months and never sharing applicators helps keep bacterial loads low.
Contact lens wearers face elevated risk as well. Handling lenses with less-than-clean hands, sleeping in lenses not designed for overnight wear, or using lenses past their recommended replacement date all increase the chance of introducing bacteria to the eyelid. If you develop a stye while wearing contacts, switching to glasses until it resolves prevents further irritation and reinfection.
Blepharitis and Chronic Lid Inflammation
Blepharitis, a condition where the eyelid margins stay chronically inflamed, is one of the strongest predisposing factors for recurrent styes in adults. It causes a crusty buildup along the lash line, clogs oil glands, and changes the composition of the oils your eyelids produce. This ongoing disruption makes it easy for bacteria to take hold again and again.
Blepharitis itself has several root causes, including an overgrowth of skin bacteria, a type of mite that lives in hair follicles, or dysfunction of the meibomian glands. It’s a chronic condition rather than a one-time event, which is why adults with blepharitis often deal with styes that keep coming back rather than a single isolated episode. Daily lid hygiene, like gently cleaning the lash line with a warm washcloth, is the cornerstone of keeping it under control.
Rosacea and Skin Conditions
Rosacea, a condition that causes facial redness and flushing, has a well-established link to eyelid problems. Ocular rosacea specifically affects the eyes and eyelids, causing dryness, irritation, and meibomian gland dysfunction. Research published in the Journal of the American Academy of Dermatology found that people who had styes during childhood were significantly more likely to develop rosacea as adults (5.5% versus 1.5% in control subjects), suggesting the two conditions share underlying inflammatory pathways.
Seborrheic dermatitis, the same condition that causes dandruff on the scalp, can also affect the eyelids and contribute to gland blockages. If you notice flaky, irritated skin around your eyebrows and lash line alongside recurring styes, an underlying skin condition may be driving both.
Diabetes and Immune Health
Adults with uncontrolled diabetes face a higher risk of styes. High blood sugar triggers the production of molecules that suppress your body’s immune defenses, making it harder to fight off the staph bacteria that cause the infection. This connection, highlighted by Duke Eye Center, means that recurrent styes in someone with diabetes can be a signal that blood sugar management needs attention.
Any condition or medication that weakens your immune system can have a similar effect. Chronic stress, poor sleep, and nutritional deficiencies don’t cause styes directly, but they reduce your body’s ability to contain the bacteria that are always present on your skin. Adults who notice styes appearing during periods of illness or high stress are likely seeing this immune connection at work.
How Styes Heal
Most styes resolve on their own within one to two weeks. The standard home treatment is a warm compress: a clean washcloth soaked in warm water, held against the closed eyelid for 10 to 15 minutes, three to four times a day. The heat helps liquefy the trapped oil, encourages the gland to open, and promotes natural drainage. Gentle massage of the area after warming can help move things along.
Resist the urge to squeeze or pop a stye. Forcing it open can spread the infection to surrounding glands or deeper tissue. Let it drain naturally. If a stye hasn’t improved after a week of consistent warm compresses, or if it’s getting larger, a doctor may prescribe antibiotic eye drops or a topical antibiotic cream. For infections that persist or spread beyond the eyelid, oral antibiotics are sometimes needed. In rare cases where a stye hardens into a painless but stubborn lump (called a chalazion), minor drainage in a doctor’s office may be necessary.
When a Stye Becomes Something More Serious
The vast majority of styes are harmless nuisances, but in rare cases the infection can spread to the surrounding skin of the eyelid, a condition called preseptal (periorbital) cellulitis. Signs that a stye has progressed beyond a simple gland infection include swelling that spreads across most of the eyelid, significant redness extending to the skin around the eye, fever, or pain that feels deeper than the bump itself.
If the infection moves past the tissue barrier that separates the eyelid from the eye socket, it becomes orbital cellulitis, which is a medical emergency. Warning signs include eye pain with movement, changes in vision, and bulging of the eye. These complications are uncommon, particularly in adults, but they underscore why a stye that’s worsening rather than improving after several days deserves professional evaluation.
Preventing Recurrent Styes
If you’re someone who gets styes repeatedly, the cause is almost certainly one of the underlying conditions or habits described above rather than bad luck. A consistent lid hygiene routine makes the biggest difference: washing your eyelids daily with warm water (or a diluted baby shampoo solution), keeping your hands away from your eyes, and replacing eye makeup regularly. For contact lens wearers, strict adherence to cleaning protocols and replacement schedules is essential.
Addressing any underlying blepharitis, rosacea, or meibomian gland dysfunction breaks the cycle for many adults. These are conditions your eye doctor can diagnose during a routine exam, and treatment is straightforward. If you’re getting more than two or three styes a year, the pattern itself is worth mentioning at your next appointment.