Could mast cell present as diarrhea/ cramps

Most of my stomach cramps and pain was associated with bartonella herx. It also had a really bad smell.

My diarrhea got noticeably better after a month of sodium valproate. People have reported a similar effect with disulfiram. I'm not sure what intestinal parasite it kills, but it's worth a try.

My guess is I had either c. diff or cryptosporidium. Cryptosporidium is an apicomplexan parasite similar to babesia, so anti-malarials would presumably work. C. Diff smells awful, but so does bart, so it's not always clear which it is.

Maybe keeping a food diary might help. I have MCAS and when I do get symptoms like you are having it is I can trace it back to something I have eaten - for me it's macadamias, too much fruit,or even the smallest amount of papaya or banana.
Hope you figure it out

It sure does. The most mast cells in your body are in your gut lining and sinuses/lungs. If I eat a wrong food like chocolate or something too fermented, diarrhea will come on within minutes.

I get the same reaction from knotweed via Buhner's protocol but that could also be the emodin

I don't know if any laboratories test stool samples, but dnaconnexions was able to detect bartonella henselae in a urine sample.