The main clinical consequence of EPI is fat maldigestion and malabsorption, resulting in steatorrhoea. Undigested fat is excreted, resulting in stools that look oily or greasy.
EPI and gut problems go together. The gut produces most of your mast cells and when you have gut problems, you're likely to have increased mast cell issues without it being MCAS, MCAD. Antihistamines, mast cell stabilisers (cromolyn sodium, ketotifen) and maybe a DAO supplement can help, as long as your system doesn't see them as an antigen too.