How long for Dermatitis Herpetiformis rash to go away?

by Liz
(Brisbane)

Hi

My 5 year old was diagnosed in Feb 2010 with coeliac disease by biopsy & blood test, he is the only one in our family that we know of. We have tried to be extremely strictly GF since then.

He had the DH rash on his knees and tops of feet then, and it all but went away except the top of one foot after about 4 months.

About 6 weeks ago he accidentally had gluten when we went to a restaurant and they told us the chips would be ok but I was suspicious after he ate them and asked the actual chef and he said they were in fact beer battered and wheat flour was used not corn flour (!)
Anyway since then the rash has come back fiercely on his elbows, knees, shins and feet on both sides and is showing no signs of going away despite us being really strict again.

I am concerned that it came back worse than it ever was and doesn't seem to be showing any signs of letting up...

What do you think? Is it a normal thing to have happen? Does it take longer and longer to go away?