The investigative compass: tracking, selective diet and support exams

In the absence of a single validated laboratory biomarker to close the diagnosis in isolation, science uses a structured investigation that transforms the patient into an active observer of their metabolism.

Tracking: according to an extensive review published in the journal Biomolecules, a detailed anamnesis combined with a symptom diary is essential to document the time window between food intake and the onset of symptoms, guiding clinical suspicion ^[1].

The therapeutic test (selective diet): guidelines published in Allergo Journal International ^[2] establish that the elimination diet acts as the real proof and the gold standard in diagnosis. The process requires a temporary selective low-histamine diet. The picture gains strong confirmation if symptoms regress during restriction and return immediately after the controlled reintroduction phase.

Blood markers: although enzyme levels can fluctuate throughout the day, studies published in the journal Wiener Klinische Wochenschrift and in the journal Food Science and Biotechnology ^[3] demonstrate that the evaluation of DAO enzyme activity in the blood serum, with values lower than ten units per millilitre, acts as a strong indicator of deficiency in the extracellular degradation capacity.

Genetic mapping: according to research in the journals Allergy and Pharmacogenetics and Genomics, specific polymorphisms in the AOC1 gene were mapped, revealing that DNA analysis can define if low enzyme production has a primary and genetic origin ^[4].

The microbiome: works released in the Journal of Physiology and Pharmacology and in the journal Nutrients prove that faecal sequencing can identify imbalances in the flora. The excessive presence of histamine-producing bacteria indicates that the syndrome has a secondary and treatable cause at the intestinal level ^[5].

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References:

[1] Biomolecules, 2020.

[2] Allergo Journal International, 2017. 

[3] Wiener Klinische Wochenschrift, 2013 / Food Science and Biotechnology. 2019.

[4] Allergy, 2011 / Pharmacogenetics and Genomics, 2007.

[5] Journal of Physiology and Pharmacology, 2018. / Nutrients, 2022.

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>> Next, read: How to get out of a histaminergic crisis.