A stye forms when bacteria, almost always Staphylococcus aureus, infect one of the tiny oil or sweat glands along your eyelid margin. The infection doesn’t usually start from the bacteria alone. It begins when the gland’s opening gets clogged, trapping oily secretions inside and creating the perfect breeding ground for bacteria already living on your skin. The result is a small, painful abscess that typically resolves on its own within one to two weeks.
How a Blocked Gland Becomes Infected
Your eyelids contain dozens of small glands that produce oils and moisture to protect the surface of your eye. When one of these glands gets blocked, its secretions thicken and stagnate. Bacteria that normally live harmlessly on your skin then colonize the trapped material, triggering an immune response. Your body sends white blood cells to fight the infection, and the resulting buildup of immune cells and dead tissue forms the red, swollen bump you see on your eyelid.
External vs. Internal Styes
Not all styes form in the same spot, because different glands sit in different parts of the eyelid. An external stye develops right at the eyelid margin, in the small oil or sweat glands near the base of your eyelashes. It usually shows up as a yellowish pustule surrounded by redness and swelling. You might notice tearing, light sensitivity, or a feeling like something is stuck in your eye.
An internal stye forms deeper inside the eyelid, in the larger oil glands embedded in the eyelid’s structural plate. These are harder to see from the outside and tend to cause pain and redness on the inner surface of the lid. Internal styes can look very similar to a chalazion in the first couple of days, which sometimes causes confusion.
Stye vs. Chalazion
A chalazion also starts as a blocked oil gland, but it’s an inflammatory reaction rather than a bacterial infection. In the first day or two, the two can be nearly impossible to tell apart. After that, they diverge: a stye stays painful and sits right at the eyelid margin, while a chalazion migrates toward the center of the eyelid and becomes a firm, painless nodule. If your bump stops hurting but doesn’t go away, it’s more likely a chalazion.
Common Risk Factors
Some people get styes once and never again. Others deal with them repeatedly. The difference often comes down to underlying conditions that keep the eyelid glands from functioning properly.
Chronic blepharitis, a low-grade inflammation of the eyelid margins, is one of the most common culprits. It creates ongoing irritation that makes gland blockages more likely. Meibomian gland dysfunction, where the deeper oil glands progressively lose their ability to secrete normally, plays a similar role. If you get styes frequently, one or both of these conditions may be driving the cycle.
Several broader health conditions also raise your risk. Rosacea, diabetes, high cholesterol, and autoimmune disorders like lupus, Sjögren’s syndrome, and rheumatoid arthritis are all associated with eyelid gland problems. Hormonal changes matter too: declining androgen levels, which can happen with aging or certain medications, reduce oil gland output and make blockages more likely. Some medications, including retinoids, estrogen-based hormone replacement therapy, and certain glaucoma eye drops, can contribute as well.
Hygiene Habits That Increase Risk
Beyond underlying conditions, everyday habits play a significant role. Touching your eyes with unwashed hands introduces bacteria directly to the gland openings. Sleeping in eye makeup or using products past their expiration date does the same. Eye makeup should be replaced at least every three months, since bacteria accumulate in the product over time.
Contact lens wearers face higher risk if they skip proper cleaning routines, handle lenses with dirty hands, or wear lenses longer than recommended. The combination of frequent eye touching, a foreign object sitting on the eye’s surface, and potential bacterial contamination from the lens case creates multiple opportunities for infection.
How Styes Heal
Most styes are harmless and resolve without medical treatment in one to two weeks. The most effective home care 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 blocked material inside the gland, helping it drain naturally. Use a clean washcloth soaked in warm (not hot) water. Don’t heat a wet cloth in a microwave, as it can get hot enough to burn the delicate eyelid skin.
While the stye is healing, avoid wearing contact lenses and eye makeup. Don’t squeeze or try to pop the bump, since that can spread the infection deeper into the eyelid or to surrounding tissue.
If a stye isn’t improving with warm compresses after several days, a doctor may prescribe antibiotic ointment or eye drops. In rare cases where a stye grows unusually large or won’t drain on its own, a doctor can lance it with a small needle to release the trapped material. This is a quick in-office procedure and speeds healing significantly.
Preventing Recurrence
If you’ve had one stye, you’re more likely to get another, especially if an underlying gland problem is involved. Daily eyelid hygiene makes the biggest difference. Gently cleaning your eyelid margins each morning with a warm washcloth removes the debris and bacteria that accumulate overnight. Some people benefit from using diluted baby shampoo or commercially available lid scrub wipes for this purpose.
Wash your hands before touching your face or handling contact lenses. Follow your lens cleaning and replacement schedule strictly. Toss old eye makeup on a regular rotation, and never share cosmetics that touch the eye area. If you have rosacea, blepharitis, or another condition linked to gland dysfunction, managing that condition reduces stye frequency over time.