<<Disclaimer: Verify this information before applying it to your situation.>>
 
The skin biopsy is usually done by a deramtologist.  Often 2 separate samples
are taken one is processed in the routine way and the other is frozen and
immunopatholgy is preformed to look for the skin deposits that distinguish DH
from.  The latter type of processing is essential. If this confirms the DH then
that all that is necessary to show that someone has a gluten sensitive
condition.
 
If the patient or the doctor feel it is nbecessary to confirm that there is a
lot of damage in the intestine then an intestinal biopsy is needed. The
intestinal biopsy does not necessarily confirm that the skin condition is DH but
makes it very likely.  The bottom line is still a GFD if either biopsy is
positive.  the dermatologist may also offer mediaction to suppress the itch.
 
Not Medical advice
Joe Murray