Hi Rosemary,
Sorry you've developed this allergic reaction, and M.E. is no fun at all! I wonder if you might want to ask your doctor about ketotifen, a different type of mast cell stabilizer. My gi doc likes it better than gastrocrom for his patients. I haven't used it, but perhaps someone on this forum will respond who has. I know it's available in Canada, and I believe people in the U.S. can order it through pharmacies in the northwest. You might want to search this site to find out how, if you want to try it. Benadryl is said to have mast cell stabilizing properties, so that could be an option if you can take it.
In addition, I wonder if you have been tested for parasites. Those are a known cause of M.E.
I have found that several supplements have helped me with gi symptoms. Of course, run any meds or supplements by your doctor before trying something new. I like l-glutamine, which helps to normalize the mucosa in the intestines. I also find that probiotics keep everything pretty normal in my digestive system. I switch among different brands, but my favorites right now are PB-8, available at health food stores and Whole Foods and online, and also Align, available online and at many pharmacies. I take 2 PB-8/day for a day or two and then cut back to one/day. I don't take it every day anymore. Align is only one/day, and now I only take it a few times/week.
I'm wondering if you can tolerate or have tried any other anti-inflammatories. I use bromelain as a digestive aid, but it's not for people who have a pineapple intolerance or allergy.
There are two doctors I know about who treat a lot of M.E. patients, in case you want another opinion on your case. They are Dr. Scot Lewey in Colorado Springs, CO, and Dr. Phillip Miner, in Oklahoma City, OK. I'm sure there are others, and your doc may be an expert in this area, too.
The last thing I want to mention, in case you haven't tried it, is the low histamine diet. This is the link to it:
http://www.urticaria.thunderworksinc.com/pages/lowhistamine.htm If you stick religiously to it for a few weeks, you may be able to figure out if certain foods are aggravating your condition.
Hope you get some relief!