Histamine intolerance is very rare. In fact, a study published in The American Journal of Clinical Nutrition reported that it probably only affects about 1% of the population. It is difficult to diagnose and can be debilitating. Note that a condition called mast cell activation disorder (MCAD) also presents similarly to histamine intolerance, which increases the difficulty of diagnosis. It’s important to talk to your doctor about an official diagnosis. In addition, there are steps you can take to identify whether you have a histamine intolerance, and ways to improve your symptoms!