According to the NIH web site,

Shingles (herpes zoster) is an outbreak of rash or blisters on the skin that is caused by the same virus that causes chickenpox — the varicella-zoster virus. The first sign of shingles is often burning or tingling pain, or sometimes numbness or itch, in one particular location on only one side of the body. After several days or a week, a rash of fluid-filled blisters, similar to chickenpox, appears in one area on one side of the body. Shingles pain can be mild or intense. Some people have mostly itching; some feel pain from the gentlest touch or breeze. The most common location for shingles is a band, called a dermatome, spanning one side of the trunk around the waistline. Anyone who has had chickenpox is at risk for shingles. Scientists think that in the original battle with the varicella-zoster virus, some of the virus particles leave the skin blisters and move into the nervous system. When the varicella-zoster virus reactivates, the virus moves back down the long nerve fibers that extend from the sensory cell bodies to the skin. The viruses multiply, the tell-tale rash erupts, and the person now has shingles.

I’m taking Famvir for my shingles, 3 times a day, for 7 days. This outbreak has manifested itself on my right arm and hand. You’d think I would have known what it was, since I had it a few years ago. I didn’t though, and was glad I showed the doctor. I have been struggling with rashes from Velcade & Doxil, so I was inclined to ignore it. The difference was that this rash hurt. The other rashes had pretty much cleared up after I started to get decadron and benedryl in my IV with each treatment, thanks to Eric’s suggestion.

Famvir is something that’s prescribed for genital herpes, so I’m embarrassed when I go to pick my rx. Dumb as this is, I loudly ask the pharmacist if I need to take my shingles medicine with food.

There’s more on my blog about my experiences with shingles. and here:
More about shingles on this blog