Some time ago I posted about our shock at discovering that my husband has celiac disease too...we never suspected that he had any problem with gluten until he went gluten free for several weeks and then drank some beer over Superbowl weekend. He broke out in a horrible scaly rash with blisters ranging from tiny to the size of a quarter.
I told him it must be dermatitis herpetiformis (aka DH), which, if true, automatically means that he has celiac disease. Many people with celiac disease have the "silent" variety, which means they have minimal symptoms or even no symptoms at all.
He went to a dermatologist, who biopsied him, but when the biopsies were negative for DH, insisted that he had psoriasis, then said it was a combination of psoriasis and eczema. The poor guy tried every cream, ointment and medication prescribed by the doctor, but nothing helped. Finally, after a couple of months of this, I told him to go back to his doctor and demand a prescription for Dapsone, which is the treatment for DH. The dermatologist again pointed out that the biopsies had been negative for the antibodies, but he couldn't argue with the fact that nothing else was working, and that the rash first showed up when my husband ingested gluten!
I've read several posts on celiac.com by folks with DH who also had negative skin biopsies but had the diagnosis confirmed by other means.
He's been on Dapsone for a couple of weeks now and the rash is healing nicely. The blisters turn a deep purple as they heal and close up....which is classic DH behaviour. I've read that the purple spots can take weeks or even months to disappear.
The fact that he's having a positive response to Dapsone confirms that it really is dermatitis herpetiformis; I've seen references to response to Dapsone in the medical literature as a validation of the diagnosis.
There is another test we could try, but he doesn't want to and I can't blame him. The old test for DH is called the iodine patch test, and consists of applying a 30% iodine solution to a small clear area of your skin. This will cause a DH outbreak in that area in those who have DH. A 30% iodine solution may not be that easy to come by, but I've read posts on celiac.com by people who soaked a bandaid in ordinary household iodine solution and applied it to their skin for several (8 or so) hours and ended up with a square patch of DH in the shape of the bandaid pad! Ow!!
In any case, my husband's skin seems to be on the mend...it's healing slowly but at least it's healing!
I'd like to re-iterate that you shouldn't feel bad about making your entire family live gluten free; you never know, you may discover that some of your family members have issues with gluten too!