A chalazion forms when one of the tiny oil glands in your eyelid becomes blocked and the trapped oils leak into the surrounding tissue, triggering an inflammatory reaction. Unlike a stye, which is a bacterial infection centered on an eyelash follicle, a chalazion is a slow-building inflammatory lump that develops deeper within the eyelid. Understanding what causes the blockage in the first place, and why some people get chalazia repeatedly, involves a mix of gland chemistry, skin conditions, and everyday habits.
How Oil Glands in Your Eyelid Get Blocked
Your eyelids contain dozens of meibomian glands, small structures that produce an oily substance designed to coat the surface of your eye and prevent your tears from evaporating. Each gland has a tiny opening along the lid margin. When that opening gets clogged, the oil backs up inside the gland. Over time, the stagnant oil thickens. Bacteria that naturally live on the skin surface can then break down the trapped oil with enzymes, producing irritating byproducts.
Those breakdown products leak into the tissue around the gland and set off a specific type of immune response called a granulomatous reaction. Your body essentially walls off the leaked material with clusters of immune cells, forming a firm, round nodule. This is why a chalazion feels like a hard pea under the skin rather than a tender pimple. Most chalazia sit deep within the lid, originating from meibomian glands embedded in the eyelid’s structural plate. A less common, more superficial type can form from smaller oil glands associated with individual eyelashes.
Blepharitis and Meibomian Gland Disease
The single biggest driver of chalazia is chronic inflammation along the eyelid margin, a condition broadly called blepharitis. When the lid edges stay inflamed over months or years, the meibomian gland openings gradually narrow. The oil inside becomes thicker and more paste-like, shifting from a clear, free-flowing liquid to a yellowish-white substance with the consistency of toothpaste. That change makes blockages far more likely.
People with diagnosed meibomian gland disease have roughly double the chance of developing a new chalazion on a separate occasion compared to people without the condition. In one large study, about 36% of patients with meibomian gland disease went on to develop at least one additional chalazion at a later date, versus 17% of patients with no underlying eyelid condition. Blepharitis on its own carried a similar elevated risk, with about 29% of those patients experiencing recurrence. This is why chalazia that keep coming back are often a signal of an underlying lid problem that needs its own management.
Rosacea and Skin Conditions
Rosacea, the skin condition known for facial redness and flushing, has a well-established connection to eyelid problems. The ocular form of rosacea causes chronic irritation of the meibomian glands and can make the eyelids persistently inflamed. While not every rosacea patient will develop a chalazion, the broader pattern of meibomian gland dysfunction that rosacea promotes creates the exact conditions that lead to blockages. If you have rosacea and notice recurring eyelid bumps, the two are likely related.
Eyelid Mites and Bacterial Overgrowth
Tiny mites called Demodex live on most people’s skin without causing problems. Two species are relevant to the eyelid: one lives in eyelash follicles, and the other burrows into meibomian and sebaceous glands. When their numbers grow too large, they can directly damage the glands and trigger inflammation.
A study of pediatric chalazion patients found Demodex mites in nearly 53% of those with chalazia, compared to zero in the control group. Mite infestation was also linked to having multiple chalazia at once and to recurrent episodes. The relationship appears to go both ways: the changes a chalazion creates in the local eyelid environment make it more hospitable to mites, and the mites in turn worsen inflammation and promote further blockages. Their waste products provoke an immune reaction, and the physical damage they cause can allow bacteria to colonize the gland more easily.
Metabolic and Systemic Risk Factors
Because chalazia are partly composed of cholesterol, triglycerides, and free fatty acids, it makes sense that conditions affecting blood lipids would play a role. Research on a large veteran population found that high cholesterol was associated with about a 29% increased odds of developing a chalazion. A separate Egyptian study found that people with recurrent, multiple chalazia had significantly higher serum cholesterol than healthy controls.
Other systemic conditions associated with increased risk include obesity (32% higher odds), diabetes (12% higher odds), hypothyroidism (8% higher odds), and gastrointestinal conditions like gastritis (54% higher odds) and irritable bowel syndrome (45% higher odds). Smoking also carried a modest but statistically significant increase in risk. The gut-related associations may seem surprising, but chronic systemic inflammation from digestive conditions can influence skin and gland function throughout the body. Hypertension was similarly linked, though likely as a marker of broader metabolic health rather than a direct cause.
Makeup, Hygiene, and Daily Habits
Anything that physically blocks or irritates the meibomian gland openings raises your risk. Sleeping in eye makeup is a common culprit, as cosmetic particles can migrate into the gland openings overnight. Old or expired makeup is particularly problematic because it accumulates bacteria over time. Mascara and eye shadow should be replaced every two to three months, and sharing eye makeup introduces unfamiliar bacteria to a sensitive area.
Poor eyelid hygiene in general allows debris, dead skin cells, and bacterial biofilm to accumulate along the lid margin. Daily face washing, with attention to the eyelid edges, helps keep the gland openings clear. If you wear contact lenses, handling them with unwashed hands introduces additional bacteria and particulate matter to the eyelid area.
Why Some People Get Chalazia Repeatedly
About 22% of people who develop one chalazion will go on to have at least one more distinct episode, and 8% will have three or more separate occurrences. Recurrence is not random. It clusters in people who have an identifiable underlying condition, whether that is meibomian gland disease, blepharitis, rosacea, Demodex overgrowth, or a metabolic factor like high cholesterol.
Racial and ethnic differences also appear in the data. Hispanic, Latino, American Indian, and Asian patients develop chalazia at higher rates than other groups, which may reflect differences in meibomian gland anatomy, oil composition, or prevalence of associated conditions. If you are dealing with chalazia that keep returning, the bump itself is a symptom. The underlying cause, whether it is a gland disorder, a skin condition, a metabolic issue, or a combination, is what needs to be identified and addressed to break the cycle.