Histamine intolerance can present in a wide range of ways and create a vast number of symptoms including headaches, nausea, vomiting, severe skin irritation and many others. These symptoms can often be provoked by many other medical conditions, so how do you specifically know that you have a histamine intolerance, and how can it be diagnosed?

The most reliable way to diagnose histamine intolerance is via an elimination diet. This can be carried out at home, by simply eliminating histamine-rich foods from your diet and watching the effect, or by visiting a hospital or clinic which may offer you a range of programs to carry out the elimination diet on site. Unless you are experiencing particularly severe symptoms, testing at home is often recommended. However, if symptoms are severe or affect you regularly, it is advisable to check for other underlying conditions which may produce the same effects.

There are of course other ways to test your body for histamine levels and indeed to measure the activity of diamine oxidase (DAO), the enzyme normally responsible for naturally fighting off rising levels of histamine, but these are not rigorous enough to provide a definitive diagnosis of symptoms. Blood and urine tests can indicate DAO and histamine levels, but may not explain the symptoms, while allergy tests are inconclusive, mainly because histamine intolerance is not a true allergy in the same way as a food allergy, for example.

The elimination diet simply consists of removing foods which are either naturally high in histamine or which release histamine readily. These can include many common foodstuffs such as eggs and milk, green teas, alcohol, aged cheeses and meats, and chocolate. If the symptoms lessen or completely disappear, then a diagnosis of histamine intolerance is relatively simple to make. It is usually recommended to remove those foods from the diet for a period of at least 2-4 weeks, to be certain that your symptoms are fully removed or consistently lessened.

Of course, the level of intolerance can vary from individual to individual - so while some people may need to completely remove a certain food from their diet, others may simply need to reduce the level of consumption and can gradually reintroduce the food once the symptoms are under control. This reintroduction is key to reinforcing the diagnosis - if symptoms reappear almost immediately, then it is clear what is causing the condition. Blanket permanent removal of a range of foods from the diet is not advisable, unless all are shown to be causing symptoms.

Those individuals who can tolerate foods in small quantities should still take care, as histamine intolerance is usually built up over a period of time - so even if you are able to consume small amounts of aged cheeses, for example, be careful how much you eat in case symptoms return.