Thanks for your answer. I will see my doctor to get a prescription for an antibody test.
Regarding the questionnaire, I definitely fit the bill: multiples food and chemical sensitivities appearing and diseappering when I am under lasting stress, white coated tongue when tired, runny nose, sneezes, itches specially lower back, dry skin, sometimes weird taste in the mouth, etc.
Unless it is a parasite--the first time I had these symptoms was after returning from vacations in Mexico very sick and having to take Flagyl to kill the critters. But obviously some survived.
The problem all test so far came back negative. But again, the standard basic parasites/candida tests--stool cultures, saliva cultures-are known to be unreliable.