Nickel chelators?

My girlfriend is recently suffering from an outbreak of nickel induced
contact dermatitis. I am wondering if there are any nickel specific
chelators with a proven track record and/or some good studies behind
them ? I found some initial medical references of chelation of dietary
mickel for tetraethylthiuramdisulfide (Antabuse) and
diethyldithiocarbamate (DDC),  

I wonder about alpha lipoic acid, acetyl n-cysteine, MSM and/or other
metal chelators, if these are specific effective against nickel as
well?

Thanks,

Ole