I have been looking at the dog food section of your site. Many years ago my dog began fitting much like the dog story reported and he also broke out in blisters. I too removed all preservatives and followed an additive free diet set down by a herbalist and dog breeder.   He was fine for a while but then the grandchildren came to stay and as doggies do he was cleaning up after them ... he now has blisters on his skin again but no fitting. My daughter and I have just gone through our cupboard looking for all the additives etc and are astounded by what we found. We will be reading the labels in future to remove the likelihood of further damage to either the children or the dogs. Thanks for the help. Denise, by email