Evaluation of Food Hypersensitivity in Children/Adolescents With Functional Dyspepsia

Food-Specific IgE, IgG, IgG4, Skin Prick Testing and Atopy Patch Testing in Children/Adolescents With Functional Dyspepsia: A Pilot Study

The main purpose of this study is to determine if standard and investigational tests used to help diagnose and treat food allergies can provide information that will be useful in determining the cause of dyspepsia and helpful in designing a treatment plan. The study will also determine if there is a connection between positive allergy tests and inflammation in the upper abdomen.

Recurrent abdominal pain is the most common type of pain in school age children and young adolescents. Over 80% of these children have pain in the upper abdomen which is diagnosed as functional dyspepsia (FD). Many of these children are also found to have eosinophilic duodenitis (ED). ED is a type of inflammation in the lining of the gastrointestinal tract characterized by an increase in eosinophils. An increase in intestinal eosinophils is a finding also seen with food allergy upon exposure to the offending antigen. The presence of intestinal eosinophilia in ED would suggest an allergic mechanism may be involved in the generation of pain and other symptoms associated with ED. Endoscopy and biopsy are used to aid in the identification of ED, which often is followed by elimination diets and food challenges to identify the offending allergen. This approach is both invasive (due to endoscopy) and cumbersome (due to the complexity and restrictiveness of the elimination diet). The value of screening for food hypersensitivities in children with ED has not been well characterized despite the theoretical links between food hypersensitivities, gut inflammation, and symptoms of dyspepsia. The current study will determine if standard and investigational tests used to evaluate food hypersensitivity have the potential to be used as biomarkers to direct treatment of children with ED.

Patch Test: food to be tested is suspended in sterile saline, placed on the skin of the back using a Finn Chamber secured with surgical tape and left in place for 48 hours.

measure specific IgE, IgG total, IgG subclass 4, skin prick tests and atopy patch tests to milk, egg, soy, corn, peanut and wheat

Determine T-lymphocytes, eosinophils and mast cell densities on duodenal biopsy samples demonstrating eosinophilia

Inclusion Criteria: Age of 8-17 years, inclusive Diagnosis of functional dyspepsia (FD) by physician based on Rome II criteria (patient group only) Undergoing endoscopy to evaluate FD following demonstration of a lack of clinical response to acid reduction therapy (patient group only) Informed permission/assent Exclusion Criteria (patient goup): Previous testing for food-specific IgE, IgG, IgG4, skin prick or allergy patch tests within the past 12 months or any previous positive result(s) for food-specific IgE, IgG, IgG4, SPT or APT to milk, egg, soy, corn, peanut or wheat; Any use of steroids or leukotriene receptor antagonists within one month prior to the study Any use of antihistamines, antihistamine-like drugs or topical steroid within two weeks prior to the study Any chronic non-gastrointestinal illness requiring regular medical care Exclusion Criteria (healthy control group) In addition to patient exclusion criteria as defined above Any current or chronic history within the previous 6 months of gastrointestinal symptoms including abdominal pain or discomfort, nausea, vomiting, bloating, diarrhea or constipation History of asthma or chronic respiratory symptoms History of allergic rhinitis or chronic sinusitis History of allergic reactions attributed to food

Neilan NA, Dowling PJ, Taylor DL, Ryan P, Schurman JV, Friesen CA. Useful biomarkers in pediatric eosinophilic duodenitis and their existence: a case-control, single-blind, observational pilot study. J Pediatr Gastroenterol Nutr. 2010 Apr;50(4):377-84. doi: 10.1097/MPG.0b013e3181c2c28a.