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Allergen Patch Test In Children With Food Allergy-related Gastrointestinal Symptoms

      BACKGROUND: Skin prick test (SPT) or specific IgE to food allergens have very few benefits in evaluation of patients suspected food allergy-related gastrointestinal symptoms. The objective of this study was to evaluate predictive value of allergen patch test (APT) in children suspected food allergy-related gastrointestinal symptoms.
      METHODS: A prospective self-controlled study was carried out in children with history of suspected food allergy-related gastrointestinal symptoms. SPT and APT using lyophilized and commercial allergens for cow's milk, egg, wheat, soy and shrimp were performed.
      RESULTS: Twenty-one patients (14 boys, median age 1.5 years) with 38 events of suspected food allergy-related gastrointestinal symptoms were enrolled into the study. Cow's milk was the most common suspected food allergens. The most common initial manifestations were diarrhea (63.6%). SPT was positive in 7/38 events (18.4%). APT using lyophilized and commercial allergens were positively correlated with history in 24/38 (63.15%) and 13/38 (34.2%) respectively. Twenty-three oral challenge tests were done. Positive challenge response was found in 6/6 (100%) if APT using lyophilized and commercial allergens were both positive, 6/7 (85.7%) if only lyophilized allergens were positive and none if only commercial allergens were positive. Agreement between APT and food challenge was significantly higher (P = 0.01) in APT with cow's milk lyophilized allergen than in commercial allergens, 0.8 and 0.4 respectively.
      CONCLUSION: APT using lyophilized allergens was more sensitive and predictive than SPT in diagnosing food allergy-related gastrointestinal symptoms in children, especially in those who were allergic to cow's milk.