DH? Negative endoscopy, elbow biopsy and blood test

[Canadian1000]

Hi everyone, I was hoping someone could give me some guidance.

My father had celiac disease and I have long wondered if I also have it.

I don’t typically have any gastro issues except your occasional bout of diarrhea and bloating which doesn’t happen often. 

I have had reoccurring rashes that appear on both elbows. They look like little bumps under my skin that are red when I scratch them.

I had a biopsy of my elbow and the diagnosis was psoriasiform dermatitis. The dermatologist said it was not DH.

I have also had a tissue transglutaminase an IgA blood test with bioplex internal control to determine if sufficient IgA is available. Results were negative.

I also had an endoscopy where the doctor took 5 specimens of my small intestine, 3 specimens of my stomach and 3 specimens of my esophagus. It was determined that everything was unremarkable and no inflammation was present.

Given my lingering elbow rash, which my derm said was not DH, how likely is it that all 3 tests produced false negatives?

I do have sebhorreic dermatitis that I routinely get on my face and chest. I use head and shoulders on the area and it goes away. I also use head and shoulders on my elbow rash (which really does resemble DH) and it typically has the same affect. The dermatologist said that I have characteristics of psoriasis and sebhorreic dermatitis on my elbows. But I have questioned as of late whether he did the biopsy correctly as I am not sure whether the biopsy was of the lesion itself or the area adjacent to it. 

Regardless of whether he did it correctly, the other two tests by two other specialists were negative.

Any thoughts?