Several physicians (incl. two profesors in allergology, regarded among highest authorities in allergology in my country) told me and insisted that people with atopic dermatitis must avoid certain foods for the rest of their lives, even if one is not allergic to these foods. The precise list of exclusions varies from doctor to doctor, but common elements include nuts, cocoa, chocolate, beer, wine, citrus fruit and others, in addition to other exclusions crafted for each patient. According to these physicians these foods are known to exacarbate atopic dermatitis in some non-specific ways, since atopic dermatitis is a complex disease which cannot be reduced to a simple IgE mediated allergy. I am not certain that I understand the theory correctly (as I mainly hearing the recommendation rather than the underlying theories), but perhaps the explanation may be that the lack of filaggrin associated with the disease makes the skin vulnerable to various irritants both from the outside and from the inside of the body (such as substances found in foods) thereby introducing food intolerances that are distinct from food allergies (and therefore will not show up in allergy tests) but nonetheless trigger skin flares. Note that these physicians do not mean the controversial IgG mediated intolerances.
I find it somehow surprising.
I spent a few days searching the internet, but I can't seem to be able to find much relevant information.
- The AAAAI explicitly states: "of particular note, eliminating a variety of foods from the diet that you are not allergic to is rarely helpful in patients with eczema". This seems to be a direct negation of this theory of the aforementioned professors, but sadly this is just a simple negation, with no explanation nor discussion.
- The ASCIA says that in general if one is not allergic to a food one needs to consume this food daily since this is how the body maintains the tolerance to a food. Therefore, if the above AAAAI claim is true, then treating AD patients with strict elimination diets that go far beyond food allergies may be beyond superfluous, it may cause significant harm to these patients, it would seem to me.
- At the same time the AAAAI expresses similar concerns wrt. alcohol: "alcohol can decrease the threshold level to trigger an allergic reaction, can decrease the time to develop an allergic reaction, and increase severity. However, alcohol itself is an unlikely allergen." This doesn't yet outright contradict the previous statement (since alcohol is not a food), but is dangerously close to such a contradiction.
- Likewise, the AAAAI says that some spice can cause skin rash even though one is not allergic to this spice. I am not certain if spice qualifies as food - if it doesn't then this statement again falls short of outright contradicting the statement from the first bullet, but is dangerously close.
- Medycyna Praktyczna (a website officially recommended by the Polish Society of Allergology) says that food intolerances can be allergic or non-allergic, that non allergic food intolerances encompass substances that cause allergy symptoms and are released in non specific ways as well as trigger mechanism such as coffee or wine.
- These two articles from the National Eczema Association (1 and 2) present a somewhat moderate approach: they say that the line between food allergies and sensitivities is blurred in inflammatory diseases such as atopic dermatitis and that therefore certain foods may trigger the immune system and cause eczema or astma without causing the severe symptoms of bonafide allergies such as anaphylaxis, that such intolerances will not always show up on allergy tests and that for some people a restrictive diet may be helpful with alleviating the symptoms, but it does not work for everyone.
- Poradnik Zdrowe (I'm not sure about the quality of this website) lists certain foods that may exacarbate allergic diseases even though the patient is not allergic to them. For example, pickles, raspberries, sausages, cheese, smoked fish contain high amounts of histamine according to this website, while chocolate, wine and herring are high in tyramine. Also tartrazine (commonly used as food a food coloring) is supposed to stimulate the production of histamine by the body.
I am frustrated by my inability to find any definitive answers, since it seems that everyone says something different. It would seem to me that the scientific community is split apart, research has not yet converged to any conclusions accepted by the majority of scientists. Is this the case? Since trying to find answers in the internet only left me with more questions, could someone briefly outline the current state of the art with regard to the issue whether or not a elimination diets that go far beyond confirmed food allergies help alleviate eczema?