Stye: what it is, how long it lasts and what the studies say

It starts with an irritation on the edge of the eyelid, like a grain of sand. The next day there is a small red, tense swelling, which hurts when you blink; sometimes a yellow dot appears on top. It is a stye, and the question that follows is always the same: how do you treat it?

The most honest answer is surprising. A Cochrane review, updated several times up to 2017, looked for controlled studies of non-surgical treatments of internal stye, warm compresses included, and did not find a single one³. Much of what is done for a stye is based on clinical experience rather than evidence. That does not mean it is wrong: it means we know less about it than is believed.

In this article

1. What a stye is
2. How long it lasts and how it develops
3. Stye: how to treat it according to the studies
4. Why it is better not to squeeze it
5. When a stye comes back
6. Frequently asked questions
7. Sources

What a stye is

The edge of the eyelids hosts many small glands: some, at the base of the lashes, produce sebum or sweat; others, deeper and called meibomian glands, produce the oily part of the tears. A stye is an acute, localised swelling, full of pus, that arises when the follicle of an eyelash or one of these glands becomes blocked and infected¹.

We speak of an external stye when it forms on the edge of the eyelid, at the base of a lash, and of an internal stye when it involves the deeper glands and bulges towards the inside of the eyelid. A review for family doctors summarises it thus: a well-defined lump on the edge of the eyelid is often a stye, while a lump in the middle of the eyelid is more often a chalazion⁸.

Stye and chalazion are the most common inflammatory swellings of the eyelid, and can appear in people with poor function of the meibomian glands or with chronic blepharitis, inflammation of the edge of the eyelid². In a survey of 80 Korean ophthalmologists specialising in eyelid surgery, redness, swelling and pain were the signs considered most useful for distinguishing a stye from a chalazion⁵: we describe the differences in our article chalazion or stye?

How long it lasts and how it develops

In the sources we have examined there is no study that has precisely measured how long a stye lasts, on average. A German review from 2022 describes a typical course: the diagnosis is almost always made by examination alone, and most of these swellings resolve spontaneously with time; in some cases, however, a small procedure becomes unavoidable².

Clinical practice gives an idea of the timescale. In the Korean survey, most surgeons continued non-surgical treatment for 5–14 days before considering a small incision to drain the stye⁵. It is a shared habit, not an experimental result, but it gives the idea: we are talking about days or a few weeks, not months.

Stye: how to treat it according to the studies

Warm compresses. They are the measure most associated with stye and appear as part of the ‘conventional’ treatment even in studies of other therapies⁶. No controlled study, however, has evaluated them on their own³. They are a reasonable practice of long tradition, but their effectiveness has not been measured.

Antibiotics. A University of California study reviewed the records of 2,712 people treated for a stye or a chalazion between 2012 and 2018. More than a third had received an antibiotic, but adding it to basic measures was not associated with a higher probability of resolution, either for stye or for chalazion⁴. It is a retrospective study, which looks at the past and cannot rule out differences between those who received the antibiotic and those who did not. And yet, in the Korean survey, 74% of surgeons preferred a topical antibiotic for stye⁵: an example of the distance between habits and evidence.

Acupuncture. Another Cochrane review, from 2017, pooled 6 randomised trials with 531 participants, all conducted in China. The trials were at high or unclear risk of bias, follow-up lasted seven days at most and the certainty of the evidence was judged low or very low⁶. They are not enough to draw conclusions.

Why it is better not to squeeze it

Squeezing a stye like a spot is an instinctive gesture. No study has tested it, so we do not know precisely how risky it is. We do know, however, that a stye is a real infection¹ and that, in a small proportion of cases, the infection can spread.

A study of 224 adults admitted to a hospital in Taiwan between 2000 and 2019 for cellulitis of the tissues around the eye, an infection of the eyelid and neighbouring tissues, looked for the starting point: after infection of the tear ducts, the second most frequent was precisely a stye, present in between 15.5% and 24.8% of cases depending on the period⁷. The figure does not say that squeezing made the infection worse; it says that a stye, in rare cases, does not remain a small problem. When a stye needs draining, the doctor does it with a small incision⁵. We check the other common beliefs in our article is a stye contagious?

When a stye comes back

Sometimes a stye returns. Reviews link this to chronic eyelid disorders, such as poor function of the meibomian glands and blepharitis². A US study reconstructed the history of 201 people who had had a stye as children: as adults, 5.5% had rosacea, an inflammatory skin disease of the face, against 1.5% of those who had not had one⁹. It is an observed association, not proof of cause. A swelling that keeps coming back in the same place or has an unusual appearance deserves a check: in these cases reviews recommend ruling out other causes with a biopsy².

Frequently asked questions

How long does a stye last?

There are no studies that have measured it precisely. Reviews describe a condition that in most cases resolves on its own², and in practice surgeons usually wait 5 to 14 days before considering a small incision⁵.

Do warm compresses work?

We do not know for certain. They are part of the usual treatment⁶, but a Cochrane review found no controlled studies that measured their effectiveness³.

Is an antibiotic ointment needed for a stye?

In a study of 2,712 people, adding an antibiotic to basic measures was not associated with more frequent resolution⁴. It is a retrospective study, so not definitive: the choice, case by case, is up to the doctor.

Is a stye contagious?

No study has measured person-to-person contagion. A stye arises from infection of a gland or a follicle in one’s own eyelid¹. We discuss this in our article devoted to common beliefs about the stye.

A stye is one of those complaints that almost everyone knows and that research has studied little. Reviews indicate that it usually resolves on its own²; for the rest, ‘we do not know’ is the most honest answer on many of the treatments in use. The firm point concerns the signs of an infection that is spreading: those must be recognised and taken to the doctor at once.