Blepharitis is an inflammation of the tip of the eyelids, in the area where the eyelashes are born. It's very common.
The most common cause is because a kind of bacteria proliferate, which normally live on our skin, but which in certain circumstances increase in number (usually because glands are clogged in the eyelids). Sometimes, it is associated with acne rosacea or seborrheic dermatitis.
There is anterior blepharitis (which affects the base of the eyelashes) and the posterior one (there is a dysfunction of the Meibomian glands, which segregate the fat of the tear) and the mixed (implies the anterior and posterior).
The typical symptoms vary depending on the severity. It may not be noticeable, but the most common are: the red tip of the eyelids, itching, scalp at the base of the eyelashes and an unusual body sensation.
In acute states, the ophthalmologist usually prescribes an antibiotic. It is usually a chronic illness. Good eyelid hygiene and palpebral massage are advised.