Antihistamines
Medications that prevent histamine from binding to receptors. However, they do not break histamine down; they only blunt its effect. In this way, they differ from DAO supplementation.
An antihistamine works like a plug. It occupies the receptor before histamine has a chance to bind to it, thereby dampening the reaction. However, the histamine does not disappear from the body—it simply has nowhere to lock in. This is how antihistamines differ from DAO supplementation, as DAO actually breaks down histamine from food right in the intestine before it can be absorbed.
H1 antihistamines relieve itching, hives, runny nose, and swelling. Newer, so-called second-generation drugs—which include cetirizine, loratadine, bilastine, fexofenadine, or desloratadine—are suitable for daily use because they cause much less sedation. The older first generation works just as well, but causes significant fatigue. Furthermore, some first-generation agents are reported to reduce DAO activity, which is inconvenient for histamine intolerance.
H2 antihistamines, such as famotidine, reduce stomach acid production. They are used for gastric issues and are sometimes combined with H1 antihistamines in histamine intolerance.
Antihistamines have their place in HIT, but they address the consequence, not the cause. The foundation remains reducing the amount of histamine from food and removing whatever blocks its breakdown. Starting or stopping any medication should always be handled by a doctor. Moreover, long-term use without a proper diagnosis can mask another underlying condition.
Related terms
The moment a mast cell empties its storage vesicles and releases histamine and other inflammatory substances into its surroundings. This can be triggered by an allergen, but also by medication, heat, or stress.
A build-up of histamine in the body from various sources that exceeds tolerance and triggers symptoms.
An independent non-profit organization (Schweizerische Interessengemeinschaft Histamin-Intoleranz) that specializes in research, education and support for people suffering from histamine intolerance (HIT) and related disorders of mast cell metabolism.
The amount of histamine the body can still break down without issues. It is not fixed and changes from day to day depending on health, medications, hormones, and stress.
Substances that release histamine from cells, worsening the symptoms of HIT.