Styes and chalazia (inflammation of the eyelid)

If you have an eyelid inflammation, your upper or lower eyelid is red and swollen – usually at the edge of the eyelid, close to the eyelashes. The swelling can grow to about the size of a pea.

Styes are painful. Pus collects in the middle of the swelling, and can often be seen as a yellow lump.

Chalazia don’t have pus in them and usually aren’t painful either. But many people find them bothersome. They often occur on the inner part of the eyelid.

Both styes and chalazia can develop on the lower or upper eyelids.

Styes occur if bacteria infect a gland in the eyelid. These are usually staphylococcus bacteria. You’re more likely to get styes if, for instance, you don’t clean your hands properly before putting contact lenses in or taking them out. The risk is also greater if the oil or sweat made in glands can’t flow out properly. This might happen if the glands are blocked by dried-up secretions or by make-up that hasn’t been removed. Styes are also more common in people who have diabetes or another disease that weakens the immune system. Further risk factors include hormonal fluctuations, stress and skin conditions like rosacea.

Chalazia usually develop because an oil gland has become blocked and is then inflamed for a long time: The oil (sebum) builds up, and more and more of the tissue becomes inflamed and hard. This type of tissue is known as granulation tissue. The inflammation isn't caused by bacteria, so there’s no pus. You’re more likely to develop a chalazion if you have a chronic skin condition like rosacea.

Inflammations of the eyelid, such as styes and chalazia, are common and can occur at any age.

Styes develop very quickly, but usually go away again soon after: The pus normally leaves the stye on its own after about a week, and the inflammation goes down.

The swelling associated with chalazia develops more slowly. It usually goes down on its own, but also more slowly than the swelling associated with styes. It can take weeks or months for chalazia to go away completely. But they sometimes don’t go away on their own.

If a stye doesn’t go away completely, it might develop into a chalazion. Or a new stye might develop in the same place.

The inflammation caused by styes might spread, for instance to the eye socket. But these complications are very rare, particularly in people who are otherwise healthy. It’s important to avoid touching the inflamed area and to pay particular attention to good hygiene – for example, by not sharing towels with other people.

It’s easy to diagnose styes and chalazia based on what they look like and the symptoms they cause: If the inflamed area doesn’t hurt, even when you push against it, it’s probably a chalazion.

Eye doctors usually test your eyesight too, and take a closer look at your eyes and eyelids with the help of a special magnifying lamp (a slit lamp).

Because styes are normally caused by staphylococcus bacteria, there's usually no need to do a swab test to find out what’s causing the infection. Other tests, such as blood tests or tissue examinations, are only needed if the doctor thinks it could be cancer or if you have a weakened immune system. Some of the tests involve quite a bit of time and effort.

Styes and chalazia usually go away on their own. Various things are thought to speed up the process. But there’s generally a lack of good research on how well they actually work. If a stye or chalazion doesn’t go away, it might be possible to remove it during a minor surgical procedure.

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.