Shingles (cont.)

Even when there is no rash, the pain of shingles may be apparent. 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.

Shingles is contagious and can be spread from an affected person to babies, 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 the contagious period is over.

Source: MedicineNet.com
http://www.medicinenet.com/shingles/article.htm