To add to this thread:
Brian, I had exactly the same reaction while using R-ALA (the brand was AST Sports Science). I had been using Life Extension brand and built up to 900mg/day, but that led to stomach pain - an ulcer like feeling. I thought maybe it was the brand, so I switched to the AST and started with 200mg -- gradually increased to 400mg (in all cases taking it on a full stomach to avoid stomach irritation, some would argue this also prevents absorbtion). But I was seeing some benefit. When I increased to 600mg (3x200), I was fine for a week or two, then began developing the rash you describe, very red, peeling skin in the area effected. I stopped the R-ALA for a day or two and the rash backed off. Took one 200 mg capsule and the rash reflamed for a day or two. Have stopped it completely and the rash is subsiding fairly quickly. May do a retry of the R-ALA in a few weeks at a low dose.

I have had similar rash like reactions to other meds used for PN, such as neurontin, cymbalta, etc. -- and consequently haven't been able to use them. My last blood test showed a deficiency in vitamin D, so I'm taking that now as well.