Diagnosing Histamine Intolerance
To date there is no clear definition of Histamine Intolerance. The diagnosis is, therefore, correspondingly difficult.
Moreover, the symptoms are unspecific. Many are similar to those of a food allergy, but there are also similarities to the signs of Fructose Malabsorption, Lactose Intolerance and, to a certain extent, to the symptoms of Celiac Disease.
Detailed patient history and symptom diary
The basis of the diagnosis is a comprehensive talk with a doctor about the way of life, nutritional habits and symptoms of the patient. A symptom diary can be useful - particularly if the patient already suspects which foods cause their symptoms. The medication a patient regularly takes also plays a role. Some medicines cause the body to release its own histamine.
Since the symptoms are unspecific, other diagnoses should be considered along with Histamine Intolerance. Allergies and mastocytosis, as well as other food intolerances should be ruled out.
If, after other causes have been ruled out, the suspicion of a Histamine Intolerance still exists, the next step is an elimination diet followed by a provocation test.
Diagnostic elimination diet
For two to four weeks, the patient should consume as little histamine as possible and complete a symptom diary. If the symptoms improve during this time, this is evidence of Histamine Intolerance.
Diagnostic provocation test
The diagnosis can be confirmed by means of a final provocation test. At best, this is placebo controlled and double blind, meaning neither patient nor tester know when the patient actually receives the histamine and when a placebo. Due to the large expenditures however, a different way is usually chosen: the patient consumes in smaller amounts histamine rich food. If they detect the known symptoms from a certain histamine load, this is considered to be evidence of the histamine intolerance. Such a provocation should take place under medical supervision, as the risk of an anaphylactic shock cannot be excluded.
Other diagnostic procedures for establishing a Histamine Intolerance
There are tests with the help of which the activity of the enzyme DAO can be determined. These tests are only conditionally conclusive.
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