Blepharitis

Blepharitis is the medical term for inflammation of the eyelids. The word "blepharitis" is derived from the Greek word blepharos, which means "eyelid," and the Greek suffix itis, which is typically used to denote an inflammation in English. Inflammation is a general term used to describe the process by which white blood cells and chemicals produced in the body protect us from foreign substances, injury, or infection. The normal body response of inflammation involves varying degrees of swelling, redness, pain, warmth, and change in function. Blepharitis is an inflammation of the eyelids, causing red, irritated, itchy eyelids, and the formation of dandruff-like scales on the eyelashes. It is a very common eye disorder with a wide variety of causes. It affects people of all ages. Although it may be uncomfortable, annoying, or unattractive, blepharitis is not contagious and generally does not cause any permanent damage to eyesight. The condition can be difficult to manage because it tends to recur. Another term for blepharitis is granulated eyelids. Angular blepharitis is a term used to describe blepharitis which primarily affects the outer corners of the eyelids.

Blepharitis involves the eyelid margins, where the eyelashes grow and the openings of the tiny oil glands near the base of the lashes are located. There may be involvement of the outer edges of the eyelid margins adjacent to the skin or/and the inner edge of the eyelid that comes into contact with the eyeball. Changes in the skin of the eyelids or the surface of the eye itself are usually secondary to the underlying disorder of the lid margins.

The cause of most cases of blepharitis is a malfunction of the oil glands of the lids. There are about 40 of these glands in each of the upper and lower lids. When these oil glands produce too much, too little, or the wrong types of oils, the eyelid margins can become inflamed, irritated, and itchy. Acne rosacea, a generalized illness of oil glands, is sometimes the underlying cause of this process.

There are some types of blepharitis that are due to disorders of the lid margin around the lashes. These include seborrheic blepharitis, which is similar to dandruff of the scalp, and infection of the lash base by Staphylococcal bacteria.

Allergies can also cause blepharitis. These include sensitivities to substances coming into direct contact with the lid margins, including mascara and contact lens solutions. Various sprays, exposure to animals, environmental chemicals, or airborne allergens can also cause blepharitis.

Less commonly, inflammation of the lids can be caused by a primary infection of the eyelids by bacteria or infestation of the lashes by tiny mites or head lice.

Blepharitis may also be caused by systemic (affecting areas throughout the body) medical conditions or skin cancers of various types.