Histaminintoleranzsyndrom (HIS) und Mastzellaktivierungssyndrom (MCAS)



What is histamine intolerance?

The histamine intolerance syndrome (HIS) is a loosely defined disease. Estimates suggest that there are 1-4% of people in Europe who suffer from this condition, who mostly women over 40 years. The typical symptoms that occur in conjunction with a “flush” (i.e. redness in the face and neck area) are: rash (urticaria), diarrhoea, abdominal pain, fatigue, difficulty in breathing and other symptoms; they often arise after eating certain histamine-rich foods.


How can an intolerance to histamine be detected?

There are no proven laboratory parameters that measured to provide a clear diagnosis of histamine intolerance. Typical symptoms and improvement under an exclusion diet, followed by the return of problems after re-introduction of histamine-rich foods may suggest the cause. A skin test (prick test) and the determination of enzyme concentrations (i.e. diamine oxidase [DAO] and histamine N-methyltransferase [HNMT]) can, however, confirm the diagnosis although this has not yet been scientifically established. Therefore, the diagnosis of histamine intolerance exists only as a diagnosis of exclusion and one which is tentative. We only carry out the appropriate tests in special cases. Further suggestions as to whether histamine intolerance is the possible cause for your symptoms, can be determined via our questionnaire:  Link to histamine questionnaire.


Is it really a histamine intolerance?

In the gastrointestinal tract, there is evidence that “overlapping syndromes” exist with irritable bowel syndrome (IBS), and drugs such as antihistamines or mast cell stabilisers can have a favourable effect in some patients who may have this disorder. "Real" allergies must be excluded.

We consider the presence of a histamine intolerance if the following criteria are met:

  • other causes have been excluded or are unable to explain the entire symptomatology
  • at least two suspected histamine symptoms (i.e. flushing, nausea/vomiting, pruritus, rhinitis, respiratory distress, dizziness, rapid heartbeat, low blood pressure) exist that require therapeutic intervention (food and pain/symptom protocol)
  • there is a significant improvement in symptoms with the histamine exclusion diet. If possible, re-exposure/provocation should be carried out with histamine.
  • there is an improvement with H1 and H2 antihistamines (histamine receptor antagonists) in combination.



Are there other ways of diagnosing this condition?

In special cases, it may make sense to conduct a gastro-/colonoscopy to obtain tissue samples for the determination of mast cells.



What is a mast cell activation syndrome?

The recently known disease, mast cell activation syndrome (MCAD), is defined as a type of hyperactivity of mast cells - these cells normally release histamine. Similar to the diagnostic procedures for histamine intolerance, current tests are inconclusive. Certain blood values can be measured and provide indications for the existence of this condition (e.g. serum tryptase). However, even here the patient’s symptoms provide the most important clues. Refer to the very detailed website of our partner: and

Which foods contain high histamine levels?

Histamine is primarily found in "mature" foods such as aged cheeses or not quite fresh fish (e.g. tuna) (fresh fish contains no histamine).

Meat: pickled goods, sausages (e.g. cervelat, bratwurst, mettwurst), cold cuts, salami, dried meat (e.g. Bündnerfleisch, Landjäger), raw ham, bacon, smoked ham, etc.

Fish: tuna, mackerel, sardines, anchovies (especially canned and smoked fish), herring and crustaceans such as crab, scampi, lobster, prawns, etc.

Cheese: all ripened cheeses, cheddar, Emmentaler, Gruyere, Parmesan, Sbrinz, Tilsiter

Vegetables: cabbage, spinach, tomatoes, eggplant, mushrooms (e.g. porcini, morels)

Fruits: strawberries, citrus fruits

Alcoholic drinks: red wine, white wine, beer





Is there anything else I can still eat?

Meat: fresh or frozen meat and poultry in all forms

Fish: fresh or frozen fish such as cod, trout, etc.

Dairy products: cheese (e.g. cottage cheese) and other dairy products such as milk, yogurt and cream

Vegetables: all other vegetables, fresh or frozen.



Are there other histamine-like substances that can trigger similar complaints?

So-called "biogenic amines" can trigger similar symptoms like that associated with histamine. These include, for example, tyramine and phenylethylamine (in cheese, chocolate, red wine, sausage, herring, anchovies, liver, sauerkraut, raspberries, avocado, beans), serotonin (in bananas, pineapple, walnuts, tomatoes, plums, avocado) and putrescine, cadaverine, spermidine and spermine (in fermented products and (heavy) red wines).

Which medications should I avoid with histamine intolerance?

In particular, iodinated agents, e.g. contrast agents in diagnostic radiology, can cause symptoms of histamine intolerance. Please discuss your condition with the respective doctor to consider whether antihistamines are useful before undergoing this type of examination.

Furthermore, painkillers such as morphine, pethidine, aspirin, NSAIDs, antibiotics (e.g. Augmentin, Zinnat), antidepressants (e.g. amitriptyline, Saroten), anti-hypertensives (e.g. verapamil), diuretics, local anaesthetics, narcotics (e.g. thiopental), cytotoxic drugs (e.g. cyclophosphamide), and other drugs are possible triggers of symptoms associated with histamine intolerance and/or mast cell activation syndrome. Please discuss your individual case with us or your own general practitioner.





Is there any treatment?

If a suspected histamine intolerance or a mast cell activation syndrome is substantiated, we usually recommend performing the histamine exclusion test with possible reintroduction in conjunction with qualified nutritional counselling to reach a diagnosis. This is often a very expensive and lengthy analysis because histamine is contained in many foods and as such, painstaking because it requires a change in diet.

The therapy consists primarily of an exclusion of histamine-rich foods and avoiding various cofactors. This includes a large number of drugs (antibiotics among others) (see above). We usually recommend the administration of medication (such as antihistamines, mast cell stabilisers), or supplementing the lack of enzyme (diamine oxidase [DAO] substitution).

A connection to other intolerances

Often when symptoms of fructose or lactose intolerance exist, these can appear as a histamine intolerance. Therefore, it makes sense to clarify these intolerances with a breath test (contact us for this specific examination). Also, coeliac disease (gluten intolerance) should always be excluded. The symptoms no longer occur after treating these intolerances with a dietary change; it is still not completely understood why this occurs.

Make an appointment with us if you think you could have an intolerance. It is important to always bring all documentation from previous investigations (i.e. laboratory blood tests, endoscopy and histology reports, reports of hospitalisation and so on) to your consultation. This facilitates the diagnosis and avoids duplication of any examinations. If possible, complete our questionnaire (link: questionnaire histamine intolerance) and also bring it with you to your consultation.

For further information, read the publication from our practice in the Swiss Medical Forum: Gastrointestinal and other ailments in histamine intolerance syndrome (HIS) and mast cell activation syndrome (MCAS) (link)