【Causes・Disease】

A chalazion is a small, usually painless, lump or swelling that appears on your eyelid. A blocked meibomian or oil gland causes this condition, which is sometimes known as a meibomian cyst. A chalazion can develop on the upper or lower eyelid. It may disappear without treatment. Unlike stye, it is a sterile inflammation without bacterial infection.
Stye is caused by a bacterial infection. The eyelids have glands and pores that secrete tears and sweat, and bacteria can become infected through these small pores, causing symptoms. Depending on the location of infection, it is classified into external stye and internal stye.

【Symptoms】

A chalazion typically appears as a painless lump or swelling on your upper or lower eyelid. chalazion may affect both upper and lower lids. It doesn’t get severe suddenly, so you can wait for a while, but it won’t heal on its own. When accompanied by inflammation, symptoms like stye may occur.
Stye causes part of the eyelid to become red and swollen, often with mild pain and itching. As the inflammation becomes stronger, redness, swelling, and pain will increase. As suppuration progresses, the swollen area may spontaneously rupture, and pus may come out. Once the pus drains out, the symptoms will begin to recover.

【Treatment】

If the chalazion doesn’t go away with home treatment, the doctor may recommend a corticosteroid injection or a surgical procedure to have it removed. Both the injection and the surgery are effective treatments.
Because stye is caused by infection, you need to use antibiotic eye drops and ointments. Occasionally, antibiotics may be taken orally for treatment. If suppuration has progressed, the doctor may make an incision to drain the pus.

【Summary】

Chalazion is not caused by infection, and stye is caused by infection. However, symptoms and treatment vary from person to person, and treatment depends on the severity.
Stye is caused by infection, but the bacteria that causes it are common bacteria that humans always carry, so it cannot be transmitted to humans. However, if you touch the affected area with dirty hands, healing may be delayed, or the infection may recur even after complete recovery. Be careful not to touch the affected area if it’s not necessary.