Sociedade Portuguesa de Alergologia e Imunologia Clínica
Abstract
Background: Foods from the legume family are used in the Mediterranean diet as a source of protein. In some cases, their ingestion triggers potentially life -threatening reactions. A high degree of immunological cross-reactivity has been described, but its clinical relevance is controversial. Aim: To carry out a clinical and laboratory characterisation of patients sensitised to leguminosae who had symptoms after the ingestion of at least one food from the leguminosae botanical family. Methods: We selected 13 consecutive patients from a food allergy outpatient clinic with allergy symptoms after the ingestion of leguminosae during the year of 2006. Case history data, skin prick tests (SPT) with commercial extracts of white bean, green bean, pea, chickpea, soya bean and peanut, and prick-to-prick (PP) tests to these legumes, both raw and boiled, and also to lupini bean and black -eyed bean were performed. Serum specific IgE and immunoblotting assays were also carried out. Results: Most patients had had symptoms with more than one legume (mean 3 legumes) with bean the most reported. The first culprit leguminosae reported was chickpea in 4 patients, bean in 4 patients and lupini bean in 3. Sensitisation to other legumes without clinical symptoms also occurred (mean 2 legumes). Anaphylaxis was described in 3 patients, to bean, soya and lupini bean, respectively. Asthma was connected to chickpea (2 patients) and to bean (1). One or more of the following symptoms: urticaria, angiooedema and oral allergy syndrome were reported by other patients. Symptomatic patients always had positive PP tests to leguminosae and most SPT were also positive. Conclusions: Lifethreatening reactions to leguminosae were found. PP tests used alone to raw and boiled legumes seem to be the most reliable diagnostic tests as in the case of other vegetable foods. However, immunoblotting assays are still important in the identification of new allergens
