Both styes and chalazia (plural for chalazion) are small, inflamed lumps that form on the eyelid. A stye (also called a hordeolum) is typically caused by a bacterial infection. Your eyelid may become inflamed, and your eye may also feel sore and scratchy. A chalazion forms when an oil gland in the eyelid becomes clogged. Your eyelid may get red, swollen, and slightly tender to touch. If a chalazion gets too large, it can press on your eye and cause blurry vision. In rare cases, the whole eyelid can become swollen. People with blepharitis (inflammation of the eyelids) are at greater risk of developing styes.
Distinguishing between a stye and a chalazion can be tricky. One difference is that a stye is usually very painful. A chalazion is usually just tender. Some styes form at the base of the eyelashes and are usually caused by an infection of the hair follicle. Others, typically caused by an infected oil-producing gland, form inside the eyelid. A chalazion begins farther back on the eyelid and rarely causes the entire eyelid to swell. Distinguishing between them is also difficult because one can sometimes develop into the other if left untreated.
What can be done? Styes and chalazia usually clear up on their own in a few weeks to a month. If you notice any sort of lump, do not attempt to squeeze or “pop” it, or you may cause more damage. Instead, apply warm compresses to your eyelid for 10 to 15 minutes, four to six times a day. If you have a chalazion, applying a warm compress or gently massaging the area helps unblock the clogged oil duct. For a stye, warm compresses help the infection resolve on its own. Avoid rubbing or touching your eyelid, which can spread the infection.
A stye usually takes a week to improve. A chalazion may take up to a month. If they don’t get better, begin to affect your vision, or keep recurring, see your doctor. A stubborn chalazion may need to be treated with a corticosteroid injection or surgically drained. For a stye that won’t heal, your doctor may prescribe an antibiotic ointment or eyedrops or, if it persists, lance the stye to allow the infection to drain.