Thank you for your inquiry.
You are correct in that the earlier literature viewed allergy to legumes as being fairly rare, but more recent references indicate that it occurs more commonly than previously thought. I have copied below a number of references which will give you more information about allergy to legumes.
In addition, I suggest that you obtain ImmunoCAPs to the legumes that are available. There are 14 legumes listed on the website Thermo/Phadia for ImmunoCAP allergens. In addition to obtaining information regarding the availability of specific legumes, each legume has a written description of IgE-mediated reactions that have been attributed to it, and an analysis of the allergens and their cross-reactivity. Included in their legume panel is lima bean. I think that this is important since you state you did intradermal skin tests to foods, and you also mentioned that the tests weren’t standardized. So, I would suggest repeat in vitro testing as an addition to the workup.
Of course, a positive test itself does not mean that your patient will react to that food, but only represents sensitivity (not necessarily clinical reactivity).
The only sure way to tell whether or not your patient will react or has reacted to a particular food, including legumes, is an oral challenge.
We are not able to say whether this child will outgrow his allergies to legumes. We only have good data in this regard for a few allergens, and the ones you mentioned are not included in that group.
Thank you again for your inquiry and we hope this response is helpful to you.
The Journal of Allergy and Clinical Immunology
Volume 101, Issue 4 , Pages 556-557, April 1998
Annals of Allergy, Asthma & Immunology
Volume 77, Issue 6, December 1996, Pages 480–482
Volume 56, Issue 3, pages 259–260, March 2001
Food Research International
Volume 44, Issue 9, November 2011, Pages 2868–2879
Ital J Pediatr. 2012 Dec 13;38:71. doi: 10.1186/1824-7288-38-71.
Urticaria and anaphilaxis in a child after inhalation of lentils vapours: a case report and literature review.
Vitaliti G, Morselli I, Di Stefano V, Lanzafame A, La Rosa M, Leonardi S.
O,U, Bronchopneumology and Cystic Fibrosis, Department of Pediatrics, University of Catania, Catania, Italy.
Background: Among legumes, lentils seem to be the most common legume implicated in pediatric allergic reactions in the Mediterranean area and India, and usually they start early in life, below 4 years of age.
Case Report: A 22 -month-old child was admitted to our Pediatric Department for anaphylaxis and urticaria. At the age of 9 months she presented a first episode of angioedema and laryngeal obstruction, due to a second assumption of lentils in her diet. At admission we performed routine analyses that were all in the normal range, except for the dosage of specific IgE, that revealed a positive result for lentils. Prick tests too were positive for lentils, while they were all negative for other main food allergens. The child also performed a prick by prick that gave the same positive result (with a wheal of 8 mm of diameter). The child had not previously eaten lentils and other legumes, but her pathological anamnesis highlighted that the allergic reaction appeared soon after the inhalation of cooking lentil vapours when the child entered the kitchen Therefore a diagnosis of lentils vapours allergy was made.
Conclusions: Our case shows the peculiarity of a very early onset. In literature there are no data on episodes of anaphylaxis in so young children, considering that our child was already on lentils exclusion diet. Therefore a diet of exclusion does not absolutely preserve patients from allergic reactions, that can develop also after their cooking steams inhalation.
Ann Allergy Asthma Immunol. 2008 Aug;101(2):179-84.
Clinical features of legume allergy in children from a Mediterranean area.
Martínez San Ireneo M, Ibáñez MD, Sánchez JJ, Carnés J, Fernández-Caldas E.
Servicio de Alergia, Hospital Nuestra Señora del Prado, Talavera de la Reina, Toledo,
Background: Lentils, chickpeas, beans, and peas are the most common consumed legumes in the Mediterranean area. However, there is little information about allergy to these legumes.
Objectives: To describe the clinical features of a Spanish pediatric population allergic to legumes (lentils, chickpeas, peas, white beans, and peanuts), to evaluate the clinical allergy to several legumes, and to determine which legume extract is most appropriate to use in the diagnosis of legume allergy by skin tests.
Methods: Fifty-four children with allergic reactions after exposure to legumes were studied. The diagnosis of legume allergy was confirmed by positive skin prick test results with legume extracts and food challenges or a recent convincing history of severe reactions.
Results: The onset of allergic reactions was at approximately the age of 2 years (median, 22 months). Skin prick test results were positive for at least 3 legumes in 38 children (70%). Positive results were more frequent to boiled extracts than to raw extracts in children with a positive oral challenge. Allergy to lentil was the most frequently diagnosed legume allergy (43 children [80%]), followed by allergy to chickpea (32 children [59%]). Oral challenges with more than 1 legume (median, 3 legumes) were positive in 37 children (69%). The most frequent induced symptoms on challenge were respiratory (rhinitis and/or asthma) and cutaneous.
Conclusion: In this population, lentils and chickpeas are the legumes that cause most allergic reactions, clinical allergy to more than 1 legume is common, and boiled legume extracts are most appropriate to discriminate between allergic and tolerant sensitized children
Int Arch Allergy Immunol. 2008;147(3):222-30. doi: 10.1159/000142045. Epub 2008 Jul 2.
In vitro and in vivo cross-reactivity studies of legume allergy in a Mediterranean population.
Martínez San Ireneo M, Ibáñez MD, Fernández-Caldas E, Carnés J.
Servicio de Alergia, Hospital Ntra. Sra. del Prado, Talavera de la Reina, Spain.
Background: Legume allergy, mainly to lentils and chickpeas, is the fifth most common cause of food allergy in Spanish children. Serological cross-reactivity among legumes is frequent, but its clinical relevance is controversial. The aim of this study was to investigate the cross-reactivity among lentils, chickpeas, peas, white beans and peanuts and its clinical relevance in pediatric patients.
Methods: Fifty-four children with clinical allergy to legumes were included. Cross-reactivity was evaluated by ELISA inhibition experiments and oral food challenges to legumes. SDS-PAGE immunoblots were conducted with raw and boiled legume extracts.
Results: ELISA inhibition experiments demonstrated more than 80% inhibition with lentil, chickpea and pea extracts. Immunoblots performed with raw legume extracts (lentil, chickpea and pea) and individual sera revealed that more than 50% of the sera identified an allergen with approximately 50 kDa in all three legume extracts. In all three boiled extracts an intense band at approximately 50 kDa was visualized using a serum pool. The oral legume challenges demonstrated that 37 children (69%) were allergic to 2 or more legumes (median 3 legumes). The most frequent associations were allergy to lentils and chickpeas (57%), allergy to lentils and peas (54%) and allergy to lentils, chickpeas and peas (43%).
Conclusions: In vitro inhibition experiments demonstrated a high degree of cross-reactivity among lentils, chickpeas and peas. Food challenges confirmed that clinical allergy to all three legumes is frequent in our cohort of Spanish children.
Phil Lieberman, M.D.