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Junior Member News - November, 2019

Food allergy: from the perspective of the public and physician

Theoretically, food allergy (FA) is an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food. Three types of immune reactions were reported: IgE, non-IgE mediated or mixed. The diagnosis of FA is made by a convincing history, double-blind, placebo-controlled food challenge, evidence of food-specific IgE, or food elimination (1), (2).

However, public assessment of FA seems to be different from the doctors’ point of view. This issue has been observed worldwide. In Asia, the prevalence of parent-reported FA in Thailand was found to be 9.3% and was declined to 1.11% after being confirmed by physician (3). Similarly, in Australia, the prevalence of self-reported FA tended to be higher than clinic-defined FA (5.5 vs 4.5, respectively) (4). Indeed, a systematic review showed that there was a very poor correlation between self-reported vs challenge-confirmed FA (5).

What are the drawbacks of this issue? Over-estimation of FA may lead to unnecessary food restriction and may affect patients’ quality of life. Recent studies found that children with food allergies endure bullying, teasing, or harassment at school. A portion of school nurses claimed that parents of food-allergenic children were overprotective or requested unreasonably (6). Therefore, it is necessary to have an educational program for the public to have the appropriate knowledge and attitude towards FA.

On the other hand, there are some factors that doctors should bear in mind in establishing the diagnosis of FA, such as the phenotype of food-dependent exercise-induced anaphylaxis. Recently, many efforts have been made to elucidate the molecular pattern of food allergens, such as component-resolved diagnostics (CRD). For instance, specific IgE to shrimp tropomyosin was determined to be more useful than skin prick test to predict clinical reactivity in patients with shrimp allergy (7). The CRD will facilitate doctors’ decision on patients’ diagnosis and prognosis.

As a part of this movement, our group is conducting a study to assess further the rates of FA using food challenge, as well as the ability of CRD in Vietnamese children. Furthermore, studies to evaluate knowledge, attitude, and behaviors towards FA will also be focused.

In conclusion, there is still a disparity between public and physician awareness about food allergy. Efforts should be made to shorten this gap by improving the educational program and the diagnostic method.

Tu HK Trinh, M.D, Ph.D
Center for Molecular Biomedicine
University of Medicine and Pharmacy at Ho Chi Minh City, Vietnam

References

  1. NIAID-Sponsored Expert Panel, Boyce JA, Assa’ad A et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol, 2010, 126:S1-58.
  2. Fiocchi A, Vincenzo F. Food allergy, 2017. Retrieved from: https://www.worldallergy.org/education-and-programs/education/allergic-disease-resource-center/professionals/food-allergy
  3. Lao-araya M, Trakultivakorn M. Prevalence of food allergy among preschool children in northern Thailand. Pediatr Int, 2012; 5492:238-243.
  4. Sasaki M, Koplin J, Dharmage SC et al. Prevalence of clinic-defined food allergy in early adolescence: The SchoolNuts study. J. Allergy Clin. Immunol. 2018;141:391–398
  5. Nwaru BI, Hickstein L, Panesar S et al. Prevalence of common food allergies in Europe: a systematic review and meta-analysis. Allergy, 2014; 69:992-1007.
  6. Twichell S, Want K, Robinson H et al. Food allergy knowledge and attitudes among school nurses in an urban public school district. Children (Basel), 2015; 2:330-34.
  7. Yang AC, Arruda LK, Santos AB, et al. Measurement of IgE antibodies to shrimp tropomyosin is superior to skin prick testing with commercial extract and measurement of IgE to shrimp for predicting clinically relevant allergic reactions after shrimp ingestion. J Allergy Clin Immunol. 2010;125:872–878.