Lip Dose Challenges in Food Allergy: Current Practice and Diagnostic Utility in the United Kingdom

IgE mediated legume allergy in east Mediterranean children: A reflection of multiple food allergies

BACKGROUND

Legumes are nutritionally valuable as an inexpensive protein source, but may cause severe allergic reactions. This study aimed to identify the characteristics of legume allergies (LAs) in Turkish children.

METHODS

A total of 87 children (4.9 (3.1-7.0) years) with LAs confirmed by either oral food challenge (OFC) or consistent history were reviewed.

RESULTS

The median age of onset was 19 (12-38) months. The most frequent LA was lentil (n = 57, 66%), followed by peanut (n = 53, 61%), chickpea (n = 24, 28%), pea (n = 21, 24%), bean (n = 7, 8%), and soybean (n = 1, 1%). From these, it was observed that 60% had multilegume (≥2) allergies and the age of onset occurred earlier compared with the single LA subgroup (18 (11-30) vs. 28 (17-42) months, p = .042). Single LA was present in peanut (51%) and lentil (16%) allergies, but not chickpea, pea, and bean. Fifteen patients had tolerated lentils before their first allergic reaction. The majority of children with LA (91.9%) were allergic to multiple foods including tree nuts (71%), hen's egg (66%), and cow's milk (49%). Seventy-eight patients (89.7%) also presented with atopic comorbidities concerning atopic dermatitis (70%), asthma (40%), and allergic rhinitis (30%). Patients with anaphylactic type of reaction (20%) had higher frequency of aeroallergen sensitization (p = .001). Lip dose challenge with legume paste predicted the result of OFC with a diagnostic accuracy of 81.82% and a positive likelihood ratio of 10.8.

CONCLUSION

In Turkey, LA is a reflection of multiple food allergies and the presence of allergy to a least frequently encountered legume is a sign of multiple LA.

Food Allergy a Constant Concern to the Medical World and Healthcare Providers: Practical Aspects

Food allergy (FA) is a condition with a growing incidence and is a constant concern for the medical world and healthcare providers. With potential symptoms including anaphylaxis, in the event of an allergic reaction the patient’s life may well be endangered. The diagnosis of FA is a continuous challenge because mild cases tend to be ignored or diagnosed late and young children with allergies are cared for by parents, who are not always able to accurately interpret symptoms. It is very important to be able to differentiate FAs from food intolerance and toxic reactions to food. An accurate diagnosis is required to provide personalized management of an FA. More sophisticated and accurate diagnostic tests, including component diagnosis and epitope reactivity, allow the provision of a directed diagnosis, a more accurate therapeutic approach, and a useful prognostic evaluation. Tests used in current practice include the specific search for serum IgE, elimination diets, oral food challenges, single, blind, and double-blind (DBPCFC) tests, as well as skin tests. The risk of anaphylaxis can be assessed by molecular diagnostics/component-resolved diagnosis (CRD) and by conducting a basophilic activation test (BAT). These tests allow a planned, personalized treatment based on molecular and clinical profiles. CRD can determine the individual profile of allergic molecular reactivity and enable the formulation of a prognostic judgment. Our article highlights the importance of knowing the immune mechanisms, diagnostics, and immunotherapies in FAs. Starting from observing exposure to food allergens, to identifying allergic reactions, analysing the severity of clinical manifestations, noting the possibilities of diagnosis, and illustrating adequate management strategies.

From Allergen Molecules to Molecular Immunotherapy of Nut Allergy: A Hard Nut to Crack

Peanuts and tree nuts are two of the most common elicitors of immunoglobulin E (IgE)-mediated food allergy. Nut allergy is frequently associated with systemic reactions and can lead to potentially life-threatening respiratory and circulatory symptoms. Furthermore, nut allergy usually persists throughout life. Whether sensitized patients exhibit severe and life-threatening reactions (e.g., anaphylaxis), mild and/or local reactions (e.g., pollen-food allergy syndrome) or no relevant symptoms depends much on IgE recognition of digestion-resistant class I food allergens, IgE cross-reactivity of class II food allergens with respiratory allergens and clinically not relevant plant-derived carbohydrate epitopes, respectively. Accordingly, molecular allergy diagnosis based on the measurement of allergen-specific IgE levels to allergen molecules provides important information in addition to provocation testing in the diagnosis of food allergy. Molecular allergy diagnosis helps identifying the genuinely sensitizing nuts, it determines IgE sensitization to class I and II food allergen molecules and hence provides a basis for personalized forms of treatment such as precise prescription of diet and allergen-specific immunotherapy (AIT). Currently available forms of nut-specific AIT are based only on allergen extracts, have been mainly developed for peanut but not for other nuts and, unlike AIT for respiratory allergies which utilize often subcutaneous administration, are given preferentially by the oral route. Here we review prevalence of allergy to peanut and tree nuts in different populations of the world, summarize knowledge regarding the involved nut allergen molecules and current AIT approaches for nut allergy. We argue that nut-specific AIT may benefit from molecular subcutaneous AIT (SCIT) approaches but identify also possible hurdles for such an approach and explain why molecular SCIT may be a hard nut to crack.

The Journal of Allergy and Clinical Immunology: In Practice 2019 Highlights

This article provides highlights of the clinically impactful original studies and reviews published in The Journal of Allergy and Clinical Immunology: In Practice in 2019 on the subjects of anaphylaxis, asthma, dermatitis, drug allergy, food allergy, immunodeficiency, immunotherapy, rhinitis/sinusitis, and urticaria/angioedema/mast cell disorders. Within each topic, practical aspects of diagnosis and management are emphasized. Treatments discussed include lifestyle modifications, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We designed this review to help readers consolidate and use this extensive and practical knowledge for the benefit of their patients.

Oral Food Challenge

Oral food challenge (OFC) is the gold standard for diagnosis of IgE-mediated and non-IgE mediated food allergy. It is usually conducted to make diagnosis, to monitor for resolution of a food allergy, or to identify the threshold of responsiveness. Clinical history and lab tests have poor diagnostic accuracy and they are not sufficient to make a strict diagnosis of food allergy. Higher concentrations of food-specific IgE or larger allergy prick skin test wheal sizes correlate with an increased likelihood of a reaction upon ingestion. Several cut-off values, to make a diagnosis of some food allergies (e.g., milk, egg, peanut, etc.) without performing an OFC, have been suggested, but their use is still debated. The oral food challenge should be carried out by experienced physicians in a proper environment equipped for emergency, in order to carefully assess symptoms and signs and correctly manage any possible allergic reaction. This review does not intend to analyse comprehensively all the issues related to the diagnosis of food allergies, but to summarize some practical information on the OFC procedure, as reported in a recent issue by The Expert Review of Food Allergy Committee of Italian Society of Pediatric Allergy and Immunology (SIAIP).