John, I've been waiting for someone to say they have this, too!
I got my red chest rash about 12 years ago. After living with it for about six months, I finally went to a dermatologist. He diagnosed it as recurring bacterial foliculitis, which is a type of acne. Using benzoyl peroxide washes kept it under control for about ten years, but it never went away until I had my Crohn's diagnosis, and went on my first round of prednisone. The prednisone made the foliculitis go away, as well as several other rashes I had (sebhorreic dermatitis and psoriasis). I guess auto-immune diseases just really confuse the bejesus out of your immune system. Getting it regulated brings things back on track. I no longer have to use any sort of benzoyl peroxide washes to keep my chest clear.
I used Oxy Wash (which was way expensive), but the best stuff I used was a soap bar that contained 10% benzoyl peroxiede. I'd use a Spin Spa (battery powered rotating shower brush) with the soap bar to really scrub the affected area. It'll take about a week to see results, but it should clear you right up. Just don't stop using it once the rash goes away, or it'll come right back.