A friend of my daughter is having horrible allergy problems. She is slowly becoming allergic to almost all foods. It started off with an allergy to seafood. She is down to only being able to eat a few things and it is affecting her lungs now. She can barely walk across a room and she’s only 24. This all started after she became an adult.
There is a freeper named Metmom who has dealt with the same thing. There are some lengthy threads about it. If you search her name, you will find them. She was eventually diagnosed with a mast cell problem. Perhaps there is something there that may help your friend.