Herpes zoster

DESCRIPTION

Herpes zoster is the medical name for shingles. Shingles is an infection caused by the varicella-zoster virus, a member of the herpes family and the same virus that causes chicken pox. The characteristic symptom is a rash of painful blisters. Shingles can appear anywhere on the body.

SHINGLES & CHICKENPOX

Shingles is caused by reactivation in the adult years of the chicken pox virus that occurred during childhood. The virus can be reactivated when the body's immunity to the virus breaks down. This may happen due to normal aging, or the body's immune system may become weakened due to stress from illness, physical or emotional stress, fatigue, poor nutrition, certain medications, chemotherapy, radiation therapy, or other factors.

Once reactivated, the virus travels along nerve fibers, usually settling in fairly isolated areas of the skin on one side of the body, but it can appear anywhere on the body. The infected area of the body usually has severe pain, itching, redness, numbness, and the development of a rash. The rash on the skin develops into small, fluid-filled blisters called vesicles. Within a few days of their appearance on the skin, the vesicles break open and form scabs. In severe cases, the rash can leave permanent scars, long standing pain, numbness, and skin discoloration.

THE EYES AND THE HERPES ZOSTER VIRUS

The eyes are sometimes affected by herpes zoster. This is due to the fact that the eyes are connected to nerves that may be infected with the herpes zoster virus.

If the infection occurs on the forehead near the eyes or on the tip of the nose, the eyes are likely to become involved. The usual shingles rash can spread from an involved area of the forehead or cheek to the upper or lower eyelids. Shingles may cause redness of the conjunctiva (the mucous membrane covering the white of the eye). It can also cause small scratches or scarring of the cornea. The scratches on the cornea may increase the risk of bacterial infection in the eye and damage to the cornea can occur. Shingles may also cause inflammation inside the eye, known as iritis or uveitis. It can also affect the optic nerve or the retina.

Herpes zoster infections of the eye can lead to redness, swelling, pain, sensitivity to light, and blurred vision. Severe or repeated episodes of herpes zoster infection are associated with other eye conditions, including glaucoma, scarring inside the eye, and cataract formation.