Histamine Intolerance: Why the DAO Enzyme Story Is Incomplete, and the Real Reason Your Low Histamine Diet Stopped Working — How to Read Your Own Histamine Pattern

If the framework above describes your case, the practical question is how to apply it to your specific pattern. Several common configurations are worth distinguishing. The DAO Limited Pattern Dominant features: clear correlation between dietary histamine load and symptoms, predictable reactions to known high histamine foods, response to DAO supplementation, response to low histamine diet that holds for as long as the diet is maintained. The bacterial production and tissue mast cell components are present but secondary. In this configuration, dietary management and DAO support are productive. The cofactors (B6, copper, vitamin C) matter. The medications that inhibit DAO should be identified and avoided where possible. The pattern is the closest fit to the standard story, and the standard interventions work for these patients in proportion to the dominance of the DAO limited component. The Mast Cell Dominant Pattern Dominant features: symptoms triggered by non food stimuli (temperature, stress, exercise, hormones, supplements, fragrances), reactions that do not predict from dietary histamine content, response to mast cell stabilizers (cromolyn, ketotifen, quercetin), variable response to dietary restriction. This is the MCAS overlap pattern and is the most common configuration in chronic histamine intolerant patients. In this configuration, dietary intervention alone will plateau