Yes, a stye is a bacterial infection. It forms when bacteria, almost always Staphylococcus aureus (staph), infect one of the tiny glands along your eyelid. The result is a small, painful, pus-filled bump that typically appears at the edge of your eyelid near your lashes. Most styes resolve on their own within one to two weeks.
How the Infection Starts
Your eyelids contain dozens of small oil-producing glands that help lubricate the surface of your eye. When one of these glands gets clogged, its secretions build up and stagnate. That stagnant environment becomes a breeding ground for staph bacteria, which already live on your skin in small numbers. The bacteria multiply inside the blocked gland, triggering your immune system to send white blood cells to fight the infection. The result is a localized abscess: a pocket of dead cells, bacteria, and inflammatory fluid that shows up as a red, swollen, tender bump.
External vs. Internal Styes
There are two types, depending on which gland is affected. An external stye infects the small oil gland attached to an eyelash follicle. You’ll see redness and swelling right at the base of a lash, often with a visible yellowish-red head. These are what most people picture when they think of a stye.
An internal stye infects a larger oil gland (called a meibomian gland) deeper within the eyelid. Instead of pointing outward, it tends to point toward the inside surface of the lid, where it shows up as a yellow bump visible when you flip the eyelid. Internal styes can be more uncomfortable because the swelling presses against the eye itself.
Both types are bacterial infections with the same underlying cause. The main difference is location and how easily you can see them.
What a Stye Feels Like
The first signs are usually redness and tenderness along the eyelid edge. The area feels sore to the touch, and your eye may feel scratchy or irritated, almost like something is stuck in it. Over a day or two, a defined bump forms. The swelling can sometimes spread to involve the entire eyelid, making it look puffy and inflamed. A visible pus-filled head often develops before the stye drains on its own.
Stye vs. Chalazion
A stye is often confused with a chalazion, but they’re different conditions. A stye is an active bacterial infection that’s painful from the start, appears at the eyelid’s edge, and can make the whole lid swell. A chalazion is a clogged oil gland without an active infection. It develops farther back on the eyelid, grows slowly, and is usually painless at first. You might not even notice a chalazion until it’s been there for a while.
A stye that doesn’t fully resolve can sometimes turn into a chalazion once the infection clears but the blockage remains. If a bump on your eyelid isn’t painful and has been there for several weeks, it’s more likely a chalazion than a stye.
Are Styes Contagious?
Styes aren’t typically spread from person to person through casual contact. However, the staph bacteria inside the bump can transfer through direct contact. Touching a stye and then touching your other eye, sharing towels, or sharing eye makeup could spread the bacteria. This is why hand hygiene matters: wash your hands frequently, avoid touching or squeezing the bump, and don’t share anything that comes in contact with your face or eyes while you have an active stye.
How Styes Heal
Most styes go away on their own within one to two weeks without any medical treatment. The standard approach at home is applying a warm compress to the affected eye for 10 to 15 minutes, several times a day. The warmth helps loosen the clogged gland and encourages the stye to drain naturally. Resist the urge to pop or squeeze it, which can push the infection deeper into the eyelid tissue.
Antibiotics aren’t needed for most styes. They’re reserved for cases where the infection is severe or spreading beyond the bump itself. If the redness and swelling extend across the eyelid or onto the skin of the face, that may signal a more serious infection called preseptal cellulitis, which requires prompt treatment. In those cases, antibiotic drops, ointment, or oral antibiotics may be prescribed depending on severity.
Why Some People Get Styes Repeatedly
Some people develop styes over and over. Recurring styes usually point to an underlying problem with the oil glands along the eyelid, a chronic condition called blepharitis. In blepharitis, the glands become persistently inflamed and produce thickened secretions that clog easily, setting the stage for repeated infections.
If you’re prone to styes, daily eyelid hygiene can help break the cycle. Gently cleaning your eyelid margins with warm water or a diluted baby shampoo removes debris and excess oil before glands have a chance to clog. Removing eye makeup completely each night also reduces the risk. For people with frequent recurrences tied to chronic gland inflammation, longer courses of oral medication may be recommended to reduce the underlying inflammation that keeps triggering new infections.