An internal hordeolum (plural: hordeola) is an inflammation of the oil glands inside the eyelid. Also called a stye, an internal hordeolum starts as a sensitive, red, swollen area just beneath the surface of the eyelid along the eyelash line.

An internal hordeolum develops from a blocked oil gland inside the eye, which prevents the pore from draining and leads to inflammation. The blockage often is the result of rubbing or using irritating products near the eyes, both of which can transfer bacteria to the area. An internal hordeolum usually comes to a head (clear or yellow fluid collects in the stye) in about 3 days, breaks open, drains, and then heals in about a week.

Usually, home treatment is all that is necessary to treat an internal hordeolum. This includes not wearing eye makeup or contact lenses; allowing the hordeolum to break open by itself; and applying warm, wet compresses to the eye area. A hordeolum that does not heal on its own should be evaluated by a health professional.