A stye looks like a small, painful pimple or boil on the edge of your eyelid. It forms when bacteria infect a gland or hair follicle along your lash line, creating a red, swollen bump that’s tender to the touch. If you’re staring in the mirror wondering what that sore spot on your eyelid is, here’s how to figure out whether it’s a stye and what to do about it.
The Classic Signs of a Stye
The hallmark symptom is a painful, localized lump right at the edge of your eyelid. It typically appears near the base of an eyelash and looks red or discolored, often with visible swelling around it. Unlike other eyelid bumps, a stye hurts. That pain is the single most reliable clue.
Other symptoms that usually accompany the bump:
- Eyelid swelling that may extend beyond the bump itself
- Increased tearing from the affected eye
- A visible pus-filled head that develops after a day or two, similar to a whitehead
- Crusting along the eyelid, especially after sleeping
Before the bump becomes visible, you may notice a tender, sore spot on your eyelid that feels slightly swollen. This early tenderness often shows up a day before the lump itself appears. If you catch it at this stage, starting warm compresses right away can help.
External vs. Internal Styes
Most styes are external, forming at the base of an eyelash where bacteria have infected the hair follicle or one of the tiny oil glands right next to it. These are the ones you can see clearly in the mirror as a bump along the lash line.
Internal styes form deeper inside the eyelid, in the oil-producing glands embedded in the eyelid tissue itself. You might not see a visible bump on the outside, but you’ll feel a painful, swollen area. Flipping your eyelid gently may reveal redness or a small raised spot on the inner surface. Internal styes tend to be more uncomfortable because the swelling presses against your eyeball, and they can take longer to resolve.
Is It a Stye or a Chalazion?
This is the most common mix-up, and for good reason: in the first two days, a stye and a chalazion can look nearly identical. Both are swollen lumps on the eyelid. But they behave differently as they develop, and telling them apart matters because they’re treated differently.
A stye stays painful and stays near the eyelid margin, right along your lash line. A chalazion, on the other hand, starts as a blocked oil gland without an active infection. Over time it becomes a firm, painless nodule that sits farther back on the eyelid, away from the lashes. If your eyelid bump has been there for more than a couple of weeks and doesn’t hurt anymore but hasn’t gone away, it’s likely a chalazion rather than a stye. Chalazia sometimes develop after a stye that didn’t fully drain.
What Causes Styes to Form
The culprit is almost always Staphylococcus aureus, a common skin bacterium. The infection starts when one of the small glands along your eyelid gets blocked. Oily secretions build up behind the blockage, creating a perfect environment for bacteria to multiply. The result is a small abscess: a pocket of pus, dead cells, and immune cells right at the surface of your eyelid.
Several things raise your risk. Chronic eyelid inflammation (called blepharitis) is one of the most common, because it thickens the oily secretions your eyelid glands produce, making blockages more likely. Touching your eyes with unwashed hands, sleeping in eye makeup, and using old or contaminated cosmetics all introduce bacteria near those vulnerable glands. Adults develop styes more often than children, partly because the oil their eyelid glands produce becomes thicker with age. People with rosacea are also more prone to them.
How Long a Stye Lasts
Most styes resolve on their own within one to two weeks. The typical pattern: the bump grows and becomes more painful over the first few days, then develops a visible pus-filled head, pops and drains on its own, and gradually heals. You’ll usually notice the bump starting to drain after about three to five days, and the pain drops significantly once that happens.
Warm compresses can speed this up considerably. Hold a clean, warm washcloth against your closed eyelid for two to five minutes at a time. Use water as warm as you can comfortably tolerate without burning yourself. You can repeat this many times throughout the day. The heat softens the blocked material inside the gland and encourages it to drain naturally. Resist the urge to squeeze or pop the stye yourself, which can spread the infection deeper into the eyelid tissue.
Signs That Something More Serious Is Happening
A straightforward stye is uncomfortable but not dangerous. What you’re watching for is signs that the infection is spreading beyond the bump itself. If redness and swelling expand across your entire eyelid or begin extending to the skin around your eye socket, the infection may be moving into surrounding tissue. This is a condition called periorbital cellulitis, and it requires prompt treatment.
Seek immediate care if you develop any of the following alongside your eyelid swelling:
- Fever
- Vision changes, including blurriness or double vision
- Pain when moving your eye
- Swelling and redness spreading across the entire eye area
- Bulging of the eye
These symptoms suggest the infection has moved deeper, which is rare but serious. A stye that hasn’t improved at all after two weeks, or one that keeps coming back in the same spot, also warrants a professional evaluation. Recurring styes sometimes point to an underlying condition like chronic blepharitis or rosacea that benefits from targeted treatment.