A review of oral food challenges in children presenting to a single tertiary centre with perceived or true food allergies

Abstract

INTRODUCTIONThe prevalence of perceived food allergies exceeds that of true food allergies, especially if the estimates are based on selfreported surveys.(1) A substantial number of parents perceive food allergies in their children based on subjective reactions or allergy tests alone.(2) Others readily draw a connection between certain foods and chronic illnesses such as eczema.(2) In addition, cross-reactive foods are avoided in children with certain food allergies, as parents fear that their children will react even if they have not been tested for or eaten these foods. This is seen in many peanut-allergic children who avoid tree nuts but have not been tested for clinical reactivity to tree nuts. Similarly, demonstrating sensitisation alone, via positive skin prick tests (SPTs) or raised serum immunoglobulin E (IgE) levels, does not necessarily equate to having an allergy; (3) and eczema flare-ups are also not always related to foods.(4) Thus, it is not uncommon for children seen at allergy clinics to be on strict elimination diets based on incomplete information regarding potential food allergies. While the vast majority of these children are not allergic to the omitted foods, they are made to adhere to diets that are similar to those of patients with life-threatening reactions to these foods; this results in unnecessary food avoidance, an impaired quality of life, potentially poor weight gain and malnutrition. (5) An oral food challenge (OFC) can be used to provide parents with an objective measure of their child's true food allergies. As no local data is available on the use of OFCs to measure the presence or absence of food allergies, a retrospective chart review was carried out to describe the indications that prompted OFCs and the outcomes of the OFCs conducted. METHODSThis study was a retrospective review conducted on patients aged ≤ 18 years who underwent OFCs at the Paediatric Allergy Clinic of the National University Hospital, Singapore, from 2008 to 2010. Most of the patients were self-referred, followed by those referred from private clinics and polyclinics. The diagnostic workup of suspected food-related reactions is shown in Fig. 1. Our centre uses published diagnostic decision thresholds for serum IgE tests and SPTs that can help predict the likelihood of an allergic reaction if a particular food is ingested. (6,7) The decision to perform the challenge was based on these thresholds and the patient's clinical history. Patients generally did not proceed with an OFC if the treating physician felt that there was a high likelihood of a positive challenge, such as in the context of a recent life-threatening reaction to that food. Some patients underwent challenges for more than one food and a few patients were challenged repeatedly for the same food if their reactions were deemed to be subjective.

Deserters on the atopic march: Risk factors, immune profile and clinical outcomes of food sensitized–tolerant infants

“…The strengths of this study include the longitudinal design, immune profiling at birth, and determination of food allergy by formal food challenge. Food challenges provide robust delineation of food sensitization phenotype in comparison with doctor diagnosis or parent report which are often inaccurate but relied upon in previous studies . A potential limitation is the SPT wheal cutoffs chosen to define cases.…”

Oral food challenges: result of a 16-year experience at a major teaching hospital in Thailand

“…Despite such findings, OFC is infrequently performed in allergy practices due to inadequate procedural set up, risk for side effects and reluctance of physicians to carry out this effort-dependent procedure in busy daily practices [ 7 8 ]. In Asia, aside from China, Japan, Korea, and Singapore, reports of OFC results are limited [ 9 10 11 12 ]. Such scarcity of information has led to uncertainty of epidemiology of food allergy from this part of World such as types of foods commonly causing reactions, severity of the reactions and of efficacy/safety of the OFC procedure.…”

Assessment of egg and milk allergies among Indians by revalidating a food allergy predictive model

“…In Asia, aside from China, Japan, Korea, and Singapore, limited information was available regarding OFC. 30 , 31 , 32 , 33 In our country, patients with suspicion of having food allergy are commonly advised for diet elimination by the clinicians from all the foods potentially causing allergic reactions without a proper medical evaluation. Such practice can cause undue stress to the families (frustration, apprehension) and difficulties in acquiring food substitutes.…”