Recurring rash

About seven years ago I had a rash that appeared on both my left and right inner thighs simultaneously at about scrotum level.  It began as a small round spot of skin that was slightly raised and itched.  At the time I was about 14 and had not been sexually active so it didn't occure to me I might have an STD.  Over the next couple weeks the rash spread until each was about the size of a quarter, and then faded almost completely away.  

In the seven years since then the area has always been visible by a very slightly darker skin color, and more recently every few months or so will flare a brighter red and feel slightly agitated (though never as badly as the initial couple weeks).  It has also spread extremely slowly until each covers about 2 inches of skin, still roughly circular.  

I have refrained from becoming sexually active because I am afraid its an STD I could pass on, but this is obviously not the best solution.  I have been meaning to get it checked out for some time, but between working full time, having no health insurance, and having no family doctor, I have been a little embarrased to get started until now.  From this description do you have any idea what it might be?  Not looking for the end-all solution, just a place to start.

[H. Hunter Handsfield, M.D.]

No STD causes a recurrent localized rash over that many years; and of course you are right that if it started before you ever had sex, it can't be an STD.

I'm not a dermatologist and can't be very informative about the cause of the rash.  However, two possibilities that come to mind are tinea (ringworm; or if it's in the groin, tinea cruris, or jock itch) or a bacterial skin infection called erythrasma.  But undoubtedly there are many other possibilities and you need to see a health care provider.  Or you might want to post your question on the MedHelp dermatology forum and see what Dr. Rockoff has to say.  But in the meantime, don't worry about an STD.  Your rash is no reason to avoid sex.

Good luck--  HHH, MD