This is a common inflammatory condition of the eyelid. It can be associated with rosacea and it is more common in people with oily skin and dandruff. It is often a chronic condition that can be treated but not cured.
Exactly what causes blepharitis is unknown. Symptoms of blepharitis include itchy, red or swollen eyelids, particularly near the lashes; crusting of the lashes or flaking of the skin around the lashes; lashes that grow in an abnormal direction or loss of eyelashes; and burning, itching, redness, and tearing of the eyes.
Treatment of blepharitis begins with regular cleaning of the eyelash margins. Warm, dilute baby shampoo applied with a washcloth or commercial cleaning solutions is a good option. Artificial tears can be used to lubricate the eyes and relieve dry eye symptoms. Warm compresses using a heated rice sock are very effective for loosening scales and debris from the lashes and diluting secretions from oil glands in the eyelids.
To make your own rice sock: Begin with a clean sock and fill it with 1 cup of uncooked rice. Tie the top of the sock. Put the sock in the microwave for about 1 minute. You want the grains to be warm but not so hot that they burn your face. Place the sock over both eyes. Leave it in place for 10 minutes.
During flares in the disease, antibiotic or steroid eyedrops or ointments may be used for a few weeks.
Blepharitis can be part of or lead to something called Meibomian Gland Dysfunction. The meibomian glands of the eyelid secrete an oily material that makes up part of the normal tear film. Dysfunction and inflammation of these glands can cause them to become filled with thick secretions and stop working. This can all cause symptoms of dry eyes (burning, itching, redness, and tearing) because of the loss of the oily material that is intended to keep the tears from evaporating away from the surface of the eye. The thick secretions that are left behind in the glands can provide a food source for bacteria that normally live on the skin.
For this condition, patients may respond to treatment with oral antibiotics for several months. These antibiotics have anti-inflammatory properties and that change the consistency of the meibomian gland secretion. Dietary supplements of omega -3 fatty acids have been shown to decrease inflammation as well.
Bacterial infection inside a meibomian glands can produce a stye (or hordeolum which is a red, sore lump near the edge of the eyelid. It can cause rather sudden swelling of the eyelid and is often very tender to the touch. The stye usually resolves on its own over about a week and often does not require medical treatment. 
Warm compresses can help with drainage. Medical treatment includes the use of antibiotic ointment or drops. Oral antibiotics are used when the infection has spread out of the gland. Surgery/Injection can be done if they do not respond to treatment.