A stye is a small abscess of the oil gland associated
with an eyelash hair follicle. It typically contains
bacteria, the cause of staph infections. When a stye
develops, a small area of the upper or lower eyelid or
the corner of the eye becomes red, tender and swollen.
Swelling subsides gradually over a period of days after
the stye develops an opening, and the pus is able to
drain out.

A chalazion, like a stye, is a swelling within the eyelid caused by inflammation of an oil
gland. A chalazion differs from a stye in that it does not contain an active bacterial
infection. A chalazion is sometimes the aftereffect of a stye but is less tender but lasts
longer.
Symptoms
Signs of a stye are pain, redness, tenderness and swelling in the area, then a small
swollen pimple-like area appears. Sometimes just the stye area is swollen, or the entire
eyelid may swell. You may also notice frequent watering in the affected eye.
Treatment
In the early stages, styes may be treated with the repeated use of warm compresses for 15
- 20 minutes. This helps to reduce the swelling and makes the lid more comfortable.
However, if the stye does not diminish or recurs, medical attention may be necessary.
This may include draining the stye along with the use of antibiotic and
anti-inflammatory medications. Styes formed inside the eyelid either disappear
completely or rarely rupture on their own, and they can be more serious. These styes
may need to be opened and drained by your eye care practitioner.