Of all allergy conditions, this is probably the most misunderstood.
Some doctors deny that it exists.
Often this allergy is overlooked, misdiagnosed as a psychiatric disorder, or other type of condition or problem. Some of the early research done for this type of allergy included using the cyto-toxic method of testing for allergens. This test is controversial to the point that many physicians disagree with it, deny it is accurate, or want it banned. It included testing of many substances that many allergy specialists disagreed with. Each of these doctors had severe allergies to food and other things which were not normally considered to be allergens.