What is histamine? Dr. Janice Vickerstaff Joneja, PhD, explains in this IHealthTube video how histamine intolerance may be misdiagnosed as, but is not the same as, an allergy. Histamine is a very important neurotransmitter with a key role in digestive, brain, and other key functions. But allergy-like symptoms can arise when histamine levels are too high.
See also Dr. Vickerstaff Joneja's comments on "What foods and drinks raise histamine levels?" below. (According to Dr. Vickerstaff, allergy tests can determine whether or not one has a food or other allergy, and if no allergy is found, then allergy-like symptoms may well reflect excess levels of histamine. It is very difficult to test for excess histamine itself, since levels may vary almost moment to moment and from person to person. So knowing foods and other factors that could raise histamine above one's tolerable limit can be helpful).
Dr. Vikerstaff Joneja is an immunologist, educator, and author of five books on food allergy management, including Digestion, Diet, and Disease: Irritable Bowel Syndrome and Gastrointestinal Function and Dealing with Food Allergies in Babies and Children.