Keith Roach, M.D., syndicated columnist

DEAR DR. ROACH: I have a pink rash of only three spots on my upper, inner left arm with skin sensitivity and some pain in the area. A couple of weeks ago, it was a paler rash, with less defined spots and discomfort that felt like there was glass there. I am a female in my 70s and have had both shingles shots. I wonder if this could be a mild case of shingles. — S.H.

ANSWER: Shingles is caused by a recurrence of the chickenpox (varicella-zoster) virus. It is restricted to one side and one body area. In fact, the word “shingles” is thought to come from the Latin word “cingulatum,” or belt, reflecting the distribution of lesions along a narrow pathway on the body. People who have had the vaccine may get a very mild case, so your thinking is quite reasonable.

The classical appearance of a shingles lesion, just like for chickenpox, is a blister filled with clear fluid on reddened skin. If you see a doctor at the time you have the rash, the laboratory can make the diagnosis of varicella-zoster virus for certain.

However, I don’t think it is shingles. The lesions in shingles are crusted over within seven to 10 days, and your rash has been there, even if paler and less defined, for three weeks. There are too many other possibilities to name, but if it continues to bother you, a visit to your regular doctor or a dermatologist should get you the answer.

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