Buckwheat pillow-induced asthma and allergic rhinitis

A Review on Epidemiological and Clinical Studies on Buckwheat Allergy

BACKGROUND

Cultivated buckwheat include two species originating from China: common buckwheat (Fagopyrum esculentum) and tartary buckwheat (Fagopyrum tartaricum). Buckwheat can cause IgE-mediated allergy, including severe allergic reactions and anaphylaxis. Exposure can occure when eating buckwheat food (food allergen), when producing or handling buckwheat food (occupational exposure) or when sleeping on buckwheat husk pillows (houeshold environmental exposure).

METHODS

A search on buckwheat allergy in the medical datbase PubMed from 1970-2020.

RESULT

A number of allergenic proteins have been identified in common buckwheat (e.g., Fag e 1, Fag e 2 and Fag e 3) and in tartary buckwheat (e.g., Fag t 1, Fag t 2, Fag t 3). Clinically relevant cross-reactivity has been described between buckwheat and peanut, latex, coconut, quinoa, and poppy seed. The prevalence of buckwheat allergy in the population can be estimated as 0.1-0.4% in Japan, Korea and buckwheat consuming areas of China. Among patients in allergy clinics in different countries, 2-7% has confirmed buckwheat allergy. School studies from Japan and Korea found 4-60 cases of buckwheat-related anaphylaxis per 100,000 school children. The incidence of severe allergic reactions to buckwheat, including anaphylaxis, can be estimated as 0.1-0.01 cases per 100,000 person-years.

CONCLUSIONS

Buckwheat allergy is a neglected allegy deserving further attention but severe allergic reactions are rare.

Occupational buckwheat allergy as a cause of allergic rhinitis, asthma, contact urticaria and anaphylaxis-An emerging problem in food-handling occupations?

Buckwheat is a known, though uncommon, allergen in occupational settings. It has recently gained popularity as healthy food and as an ingredient in gluten-free diets. We describe a series of six patient cases with occupational immediate allergy to buckwheat. Three cooks, two bakers, and a worker in a grocery store were occupationally exposed to buckwheat flour and developed immediate allergy to buckwheat, which was confirmed by skin prick testing and measurement of specific immunoglobulin E antibodies. Four of the patients were diagnosed with occupational asthma, four with occupational rhinitis, and two with occupational contact urticaria caused by buckwheat. Three of the six patients suffered anaphylaxis as consequence of their occupational buckwheat allergy after ingestion of food that contained buckwheat. The high rate of life-threatening reactions, together with a short exposure time to buckwheat before sensitization occurred in these cases, highlights the importance of a detailed occupational history and a high index of suspicion for occupational food allergens.

Understanding buckwheat allergies for the management of allergic reactions in humans and animals

Buckwheat allergy is an immediate hypersensitivity reaction that includes anaphylaxis mediated by specific IgE antibodies. Several IgE-binding proteins in common buckwheat have been reported to be possible clinically relevant buckwheat allergens. Although common buckwheat is popularly consumed in Asia, buckwheat allergy is becoming a serious problem not only in Asia but also in Europe. In addition, common buckwheat has also been found to be a causative agent of allergic symptoms in animals. In recent years, in addition to conventional food allergy testing methods, the development of component-resolved diagnosis (CRD) has improved the diagnostic accuracy of food allergy. The identification of allergens is essential for the construction of CRD. In this review, we introduce the different types of buckwheat allergens and discuss how each buckwheat allergen contributes to the diagnosis of buckwheat allergy. We also present the analysis of buckwheat allergen that will help reduce the allergenicity of common buckwheat and reduce buckwheat allergen molecules. These findings may be beneficial in overcoming buckwheat allergies in humans and animals.

Food-Induced Anaphylaxis: Role of Hidden Allergens and Cofactors

Food anaphylaxis is on the increase, with those who have an allergy to peanuts, tree nuts, milk, and seafood at the highest risk of developing such a reaction. However, the diet in many societies is increasingly varied, much of the food consumed is prepared outside the home, and meals are often composed of many different ingredients. Anaphylaxis may occur to a composite food, and it may be unclear whether the reaction is due to contamination or to a culprit allergen present in an added ingredient. Composite foods can contain many allergic proteins present in small amounts, which do not always have to be labeled, unless they feature in European or US labeling regulations. These "hidden" allergens include mustard, celery, spices, lupine, pea, natural food colourings, and preservatives, but can occasionally include allergenic material from contaminants such as cereal mites. Hidden allergens can provoke severe reactions to seemingly unconnected foods which might then lead to a diagnosis of idiopathic anaphylaxis. The same problem can arise with two well-known types of food allergy; wheat-dependant exercise induced anaphylaxis and allergy to non-specific Lipid Transfer Protein allergens, both of which might only manifest when linked to a cofactor such as exercise. Many of these risk factors for food anaphylaxis have a common link; the public's engagement with popular concepts of health and fitness. This includes the development of a food and exercise culture involving the promotion and marketing of foods for their health-giving properties i.e., meat substitutes, wheat substitutes, supplements and alternative, or "natural" remedies for common ailments. Some of these foods have been reported as the cause of severe allergic reactions, but because they are often viewed as benign unlikely causes of severe allergic reactions, could be considered to be hidden allergens. The best resource to elicit the likelihood of a hidden allergen provoking an allergic reaction is to take a detailed history of the allergic reaction, presence of co-factors, foods suspected, type of food and where it was consumed. A good knowledge of commonly used ingredients, and list of potential hidden allergen suspects are essential tools for the food allergy detective.

Seven Chinese patients with buckwheat allergy

Buckwheat is an important crop in China and is also known as an important potent allergen in the population. Here, we report a series of 7 Chinese patients with buckwheat allergy, which has never been reported previously in China. Mean age was 20 years at diagnosis. Patients' symptoms were respiratory, gastrointestinal, cutaneous, and anaphylactic. The routes of exposure were varied. Laboratory allergy test showed that buckwheat-specific IgE levels in all patients were remarkably elevated. Allergen avoidance was the best treatment in these cases. The data suggest that buckwheat can induce various clinical manifestations. Anaphylaxis might be characterized by severe symptoms. Buckwheat pillow is an important source of exposure to buckwheat in China and other Asian countries. Therefore, public education with effective avoidance measures should be an integral part of the management strategy.

IgE-binding epitopic peptide mapping on a three-dimensional model built for the 13S globulin allergen of buckwheat (Fagopyrum esculentum)

The three-dimensional model built for the 13S globulin allergen of buckwheat (Fagopyrum esculentum) consists of three protomers exhibiting the cupin motif, arranged in a homotrimer around a three-fold symmetry axis. Using the SPOT technique, 11 continuous IgE-binding epitopic peptides were characterized on the molecular surface of the 13S globulin allergen of buckwheat. Except for one of them, they all correspond to well exposed regions containing electropositiveley and/or electronegatively charged residues, which cover up to 40% of the molecular surface of the allergen. Some of these epitopes come in close contact to probably create more extended discontinuous epitopes, especially those located on the edge of the 13S globulin homotrimer. Half of the identified epitope peptides remain unaltered in a core structure protected against hydrolysis by digestive proteases and are thus assumed to promote the allergenicity of the 13S globulin. In addition, a few of these epitopes coincide with sequential IgE-binding epitopes previously characterized in soybean 11S globulins, that could account for the IgE-binding cross-reactions observed between soybean and buckwheat in Western blot experiments.

[Anaphylactic shock due to French galette. Type I allergic reaction to buckwheat]

A 37-year-old woman twice developed a life-threatening anaphylactic reaction after eating galettes, a special French pancake from Brittany. She had tolerated ordinary pancakes and crepes for many years. The allergological work-up revealed a Type I allergic reaction to buckwheat contained in the galettes. A prick test to buckwheat was positive and specific IgE antibodies to buckwheat were found in her serum. In contrast to wheat, buckwheat is not a cereal but a gluten-free knot-grass, initially from Asia. Whenever a patient suffers from allergic reactions due to pastries, a buckwheat allergy should be considered.