Meibomianitis is an inflammation of the meibomian glands, a group of oil-secreting (sebaceous) glands in the eyelids. These glands have tiny openings to release oils onto the edges of the eyelids.
Any condition that increases the thickness of the oily secretions of the meibomian glands will allow excess oils to accumulate on the edges of the lids. This allows bacteria, which are normally present on the skin, to grow.
Excess and thickened oily secretions can be caused by allergy, adolescence, or general skin conditions such as rosacea. Meibomianitis is often associated with blepharitis, which can cause an accumulation of dandruff-like substance on the eyelids.