What  is shingles? What causes shingles? 

Shingles is a skin rash caused by the same virus that causes chickenpox. This virus is called  the Varicella zoster virus (VZV) and is in  the herpes family of viruses. After an individual has chickenpox, this  virus lives dormant  in the nervous system and is never fully cleared from the body. Under certain circumstances, such as emotional  stress, immune deficiency (from AIDS or chemotherapy),  or with cancer,  the virus reactivates  and causes shingles.

In most cases of shingles, however, a cause for the reactivation of the virus is never found. Anyone who has ever had chickenpox is at risk for  the development of shingles, although it occurs most commonly in people over the age of 60. It has been estimated that up to 1,000,000 cases of shingles occur each year in  the U.S. 

The herpes virus that causes shingles  and chickenpox is not  the same as the herpes viruses that causes genital herpes (which can be sexually transmitted) or herpes mouth sores. Shingles  is medically termed herpes zoster. 

What are shingles symptoms and signs? How long does shingles last? 

Before a rash is visible, the patient  may notice several days to a week  of burning pain  and sensitive skin. When the characteristic rash is not yet apparent, it may  be difficult to determine the cause  of the often severe pain. Shingles rash starts as small blisters on a red base, with new blisters continuing to form for three to five days. The blisters follow  the path of individual nerves that come out  of the spinal cord in a specific "ray-like" distribution (called a dermatomal pattern)  and appear in a band-like pattern on an area of skin.  The entire path of the affected nerve may  be involved, or there  may be areas in the distribution of the nerve with blisters and areas without blisters. Generally, only one nerve level is involved. In  a rare case, more than one nerve will be involved. Eventually, the blisters pop,  and the area starts  to ooze.  The affected areas will then crust over  and heal. The duration of the outbreak may take three  to four weeks from start to finish. On occasion, the pain will be present  but the blisters  may never appear. This can be a very confusing cause of local pain.

Is shingles contagious? 

Yes, shingles is contagious. Shingles can be spread from an affected person to children or adults who have not had chickenpox. But instead of developing shingles, these people develop chickenpox. Once they have had chickenpox, people cannot catch shingles (or contract  the virus) from someone else. Once infected, however, people  have the potential  to develop shingles later in life. 

Shingles is contagious to people who have not previously had chickenpox,  as long as there are new blisters forming and old blisters healing. Similar to chickenpox, the time prior to healing or crusting of the blisters is the contagious stage of shingles. Once all of the blisters are crusted over, the virus can no longer be spread and shingles is no longer contagious.