It could be something as simple as one of the family "double dipping" in the mayo or what have you, when they make a sandwich. They might not want to mention it because they don't think it would hurt, and "Mom's already emotional enough". Or it could be kissing your husband after he eats a sandwich. Or the kids after they have been eating gluten.
And psoriasis IS a symptom of celiac. I know. I have it, and after going gluten-free it went away. It comes back if I've been glutened.
Well now i will have to investigate farther because whatever it is i need to find it and get rid of it. Thanks for all the advice. I have the psorasis too...i know she will eventually diagnosed with celiac but of course when the blood work came back negative her doctor and dad both just looked at me like i was crazy.