A sty (also spelled “stye”) is a small, painful bump on or inside your eyelid caused by an infected oil gland. It looks similar to a pimple and typically resolves on its own within one to two weeks. While sties are common and usually harmless, they can be uncomfortable and sometimes lead to complications if handled incorrectly.
What Causes a Sty
Your eyelids contain dozens of tiny oil glands that help lubricate your eyes. When one of these glands becomes clogged, bacteria that naturally live on your skin can get trapped inside and trigger an infection. The gland swells, fills with pus, and forms the red, tender bump you see on your eyelid.
There are two types. External sties are the most common and form at the base of an eyelash follicle, right at the edge of your eyelid. Internal sties develop deeper inside the lid, in larger oil glands called meibomian glands. Internal sties tend to be more painful because they press against the eyeball, and they can sometimes cause more widespread swelling. Staphylococcus bacteria are the usual culprit in both cases.
Chronic eyelid inflammation (blepharitis) is one of the biggest risk factors. When the edges of your eyelids stay irritated over time, oil gland secretions thicken and stagnate, making blockages more likely. Other risk factors include using expired eye makeup, not removing cosmetics before bed, and poor contact lens hygiene. Replace mascara at least every six months, since bacteria grow readily in older makeup products.
What a Sty Looks and Feels Like
The hallmark of a sty is a painful, red lump at the eyelid’s edge. It often comes to a visible head, much like a whitehead pimple. You may also notice your eyelid swelling beyond just the bump itself, along with watering of the eye and a gritty or scratchy sensation when you blink. Some people feel like there’s something stuck in their eye. The area is usually tender to the touch, and the pain can range from mild annoyance to a sharp, throbbing ache, especially with internal sties.
Sty vs. Chalazion
A chalazion looks similar to a sty but behaves differently. While a sty is very painful and usually appears right at the eyelid’s edge near a lash, a chalazion is typically painless and develops farther back on the lid. Chalazions form when a blocked oil gland becomes inflamed without an active bacterial infection. They tend to grow larger and more slowly than sties, and they can persist for weeks or months. In some cases, an untreated sty evolves into a chalazion once the initial infection clears but the blocked gland remains swollen.
How to Treat a Sty at Home
Warm compresses are the single most effective home treatment. Soak a clean washcloth in warm water, wring it out, and hold it gently against your closed eyelid. The American Academy of Ophthalmology recommends applying the compress for about five minutes at a time, two to four times per day. The heat softens the clogged oil and encourages the gland to drain on its own. Avoid using continuously hot compresses, since prolonged warmth can dilate blood vessels and actually increase swelling.
Beyond compresses, keep the area clean and resist the urge to rub or touch the bump. Don’t wear eye makeup or contact lenses while the sty is active. Most sties will rupture, drain, and heal within one to two weeks with nothing more than consistent warm compresses and basic hygiene.
Why You Should Never Pop a Sty
It can be tempting to squeeze a sty the way you would a pimple, but this is one of the worst things you can do. Squeezing releases bacteria-filled pus that can spread the infection to surrounding tissue. It can also push bacteria deeper into your skin and damage the delicate structure of your eyelid. Let the sty drain naturally, or seek medical help if it doesn’t.
When a Sty Needs Medical Treatment
If a sty doesn’t improve after a couple of weeks of warm compresses, a doctor may prescribe antibiotic eye ointment or drops to help clear the infection. If the infection has spread beyond the bump to the surrounding eyelid or eye, oral antibiotics are sometimes necessary. For sties that grow very large or refuse to drain, a doctor can lance the bump with a small needle to release the trapped pus and speed healing.
In rare cases, an untreated or mishandled sty can progress to periorbital cellulitis, a serious infection of the tissue surrounding the eye. Signs of this include significant swelling that spreads across the entire eyelid, fever, or pain that worsens dramatically. This requires immediate medical attention.
Preventing Sties From Coming Back
Some people get sties once and never again. Others deal with them repeatedly, especially if they have underlying blepharitis. Keeping your eyelids clean is the best defense. Gently washing your lash line with diluted baby shampoo or a lid scrub can prevent oil glands from clogging. Always remove eye makeup before sleeping. Replace mascara and eyeliner regularly, since bacteria accumulate in the product over time. If you wear contacts, wash your hands thoroughly before handling them and follow your replacement schedule strictly.
If you notice chronic redness, flaking, or irritation along your eyelid margins, treating that inflammation early can stop sties from forming in the first place.