What were taking about isn't an auto immune disease, it's a bacterial infection in your intestine. And a specific blood test, that your doctors very likely wouldn't test for, is necessary for this. And even then, the blood test is the LEAST accurate test for this.
The accurate tests being a breath test and endoscopy.
I have been reading about this all day and think that it is a pretty good hypothesis. The correlation between H. pylori and skin conditions such a Psoriasis and lichen Planus is prevalent.