Workshop on Experimental Methodology for Clinical Studies of Adverse Reactions to Foods and Food Additives

Food immunotherapy has been the focus of several allergy research initiatives over the last decade. Although many questions remain unanswered, the evidence suggests that this treatment might be available in the near future outside clinical trials. Additionally, pharmaceutical companies, in light of promising early-stage results, have shown interest in developing commercially available products, thus increasing the likelihood that new immunotherapy treatments will be introduced, especially for peanut allergy. Given this optimistic scenario and given the prospect of rigorously developed products for peanut allergy treatment, each allergist will need to understand the specificities of these treatments and their expected efficacy and adverse event profiles. Thus it is imperative that allergists understand the differences in efficacy between the different management options, as well as how the end points are measured in the relevant literature. However, given the significant heterogeneity detected among food immunotherapy trials, this task might not be as straightforward as desired. This article aims to dissect how primary efficacy end points are defined and assessed to facilitate understanding of the design of these trials and the potential effect that this variation might have on the reported outcomes.

Hypersensitivity to the chicken egg is a widespread disorder mainly affecting 1–2% of children worldwide. It is the second most common food allergy in children, next to cow's milk allergy. Egg allergy is mainly caused by hypersensitivity to four allergens found in the egg white; ovomucoid, ovalbumin, ovotransferrin and lysozyme. However, some research suggests the involvement of allergens exclusively found in the egg yolk such as chicken serum albumin and YGP42, which may play a crucial role in the overall reaction. In egg allergic individuals, these allergens cause conditions such as itching, atopic dermatitis, bronchial asthma, vomiting, rhinitis, conjunctivitis, laryngeal oedema and chronic urticaria, and anaphylaxis. Currently there is no permanent cure for egg allergy. Upon positive diagnosis for egg allergy, strict dietary avoidance of eggs and products containing traces of eggs is the most effective way of avoiding future hypersensitivity reactions. However, it is difficult to fully avoid eggs since they are found in a range of processed food products. An understanding of the mechanisms of allergic reactions, egg allergens and their prevalence, egg allergy diagnosis and current treatment strategies are important for future studies. This review addresses these topics and discusses both egg white and egg yolk allergy as a whole.

Clinical and laboratory evidence increasingly supports the notion that food allergy plays a role in the pathogenesis of atopic dermatitis (AD). However, the prevalence of clinically significant food hypersensitivity among children with AD remains an unanswered question.

To prospectively determine the prevalence of IgE-mediated food hypersensitivity among patients referred to a dermatology department for evaluation of AD, and to analyze the clinical relevance of these sensitizations in AD.

We studied 44 infants of both sexes, aged less than 12 months old, who attended the dermatology department with symptoms of AD. Compliance with Hanifin-Rajka criteria was confirmed and the severity of AD was evaluated using the SCORAD index. IgE-mediated sensitization to cow's milk, alpha-lactalbumin, beta-lactoglobulin, casein, eggwhite, egg-albumin, ovomucoid and foods introduced into the diet was studied using the skin prick test (SPT) and measurement of specific serum IgE (sIgE) by CAP System fluorescein-enzyme immunoassay.

Cow's milk, as well as suspected foods from the clinical history or those with a positive SPT and/or sIgE, were withdrawn from the diet to evaluate improvement in AD, and an open controlled challenge test was carried out.

Of the 44 patients studied, sensitization to foods was detected in 27 (61%). No changes were observed in AD during the elimination diet or when the eliminated foods were subsequently reintroduced into the diet. The results of open controlled food challenges were positive in 12 patients (27 %).

A high prevalence of food sensitization was found in infants with AD. The most frequent sensitization observed was to egg, although with little clinical relevance since this food had not been introduced into the diet.

In the sample studied, the clinical relevance of the observed food hypersensitivities was confirmed in relation to AD. Further studies are required to confirm these results.

Tremendous progress has been made in our understanding of food-based allergic disorders over the past 5 years. Recent epidemiologic studies suggest that nearly 4% of Americans are afflicted with food allergies, a prevalence much higher than appreciated in the past. In addition, the prevalence of peanut allergy was found to have doubled in American children less than 5 years of age in the past 5 years. Many food allergens have been characterized at the molecular level, which has contributed to our increased understanding of the immunopathogenesis of many allergic disorders and might soon lead to novel diagnostic and immunotherapeutic approaches. The management of food allergies continues to consist of educating patients on how to avoid relevant allergens, to recognize early symptoms of an allergic reaction in case of an accidental ingestion, and to initiate the appropriate emergency therapy. However, the recent successful clinical trial of anti-IgE therapy in patients with peanut allergy and the number of immunomodulatory therapies in the pipeline provide real hope that we will soon be able to treat patients with food allergy.