title: Role of atopy patch test for diagnosis of food allergy-related gastrointestinal symptoms in children.
abstract: BACKGROUND
  Double-blind, placebo-controlled food challenge is the gold standard for diagnosing food allergy. However, it is a time-consuming procedure and requires onsite medical supervision and resuscitating medicines and devices on hand. The objective of this study was to compare the atopy patch test (APT) with the oral food challenge test (OFC) in children with suspected food allergy-related gastrointestinal (GI) symptoms.
  
  
  METHODS
  A prospective self-controlled study enrolled children with a history of suspected food allergy-related GI symptoms. Skin prick test (SPT) and APT using lyophilized and commercial allergen extracts for cow's milk, egg, wheat, soy, and shrimp were evaluated, and OFC was performed.
  
  
  RESULTS
  Thirty-nine patients (25 boys, median age 2.4 yrs) with 76 events of suspected food allergy-related GI symptoms were enrolled. SPT was positive in 11/76 events (14.5%). Sensitivity, specificity, predictive values, and likelihood ratio were calculated related to the food challenge outcome. Of 41 OFC, 30 (73.2%) were positive. APT using lyophilized allergen extracts yielded high sensitivity (80%) and high positive predictive value (85.7%). APT using commercial allergen extracts yielded low sensitivity (30%) but high specificity (90%). The negative predictive value of APT using lyophilized and commercial allergen extracts was 53.8% and 32.2%, respectively. All cases with positive APT using lyophilized allergen extracts together with positive SPT also had positive OFC.
  
  
  CONCLUSIONS
  In contrast to commercial extracts, APT with lyophilized allergen extracts is reliable, safe, and maybe useful for the diagnosis of suspected food allergy-related GI symptoms in children. OFC is still needed in most of the cases.
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Onsuree
authors.initials: O
authors.lastname: Boonyaviwat
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Punchama
authors.initials: P
authors.lastname: Pacharn
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Orathai
authors.initials: O
authors.lastname: Jirapongsananuruk
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Pakit
authors.initials: P
authors.lastname: Vichyanond
authors.affiliation: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Nualanong
authors.initials: N
authors.lastname: Visitsunthorn
mesh_terms: D000284:Administration, Oral; D000485:Allergens / Q000276:immunology; D000818:Animals; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications / Q000175:diagnosis*; D005767:Gastrointestinal Diseases / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D007114:Immunization; D008297:Male; D008894:Milk Proteins / Q000276:immunology; D010328:Patch Tests / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D000485:Allergens; D008894:Milk Proteins
keywords: atopy patch test; commercial allergen extract; food allergy; food challenge test; gastrointestinal symptoms; lyophilized allergen extract; skin prick test