Rash from Plastic?

I am a 28 year old male and about 4 years ago I noticed a small rash on my upper chest and on my kneecaps. Every time it appears it is in the same place on my body. It is extremely small, looking more like tiny red dots or splotches. When it shows up, it usually disappears within 10 min. It is not bumpy in the least bit. I had two doctors check it out and the both told me it was nothing to worry about. One Doctor said it might be a reaction to a certain chemical or plastic. It is driving me crazy not knowing what this is. My questions are:

1. Is this "reaction" possible?
2. Is this common?
3. Have you ever heard of something like this?

Thank you.

[Alan Rockoff, MD]

1.  I never heard of such a reaction to plastic.  (A reaction wouldn't go away in 10 minutes.)
2. No, but lots of people get vague, hard-to-pin-down skin changes that don't mean anything.
3.  Same answer as #2.

I think you should not let minor things like this drive you crazy.  If two doctors suggested you not worry, I think you should take their advice.

Best.

Dr. Rockoff