In our family we run the gamut from IBD, IBS and Fap...many cousins (no parents) have died either directly or indirectly from FAP...as for the IBD it seems to have touched a large swath on the Cousin level of our family one way or the other.
I have no info on previous generations but it seems to be the up and coming disease in my family.
Because alergies are a manifestation of the whole autoimmune disease I think the question is more an autoimmune question than an IBD in our case.
Sharon