title: Atopy patch test (APT) in the diagnosis of food allergy in children with atopic dermatitis.
abstract: BACKGROUND
  Atopic Dermatitis is a chronic inflammatory skin disease. Food allergens are important in the pathogenesis in 1/3 of the cases. Several mechanisms are involved in the pathogenesis of Atopic Dermatitis. Immediate reactions are identified by both measurement of specific IgE and skin prick test. Atopy Patch Test seems to be relevant in the investigation of patients with suspected delayed-type reactions.
  
  
  OBJECTIVE
  To evaluate the standardization of this method concerning allergen concentration, occlusion time and interpretation, and determine the specificity and sensitivity of the Atopy Patch Test according to the skin prick test and specific IgE levels in food allergy diagnosis in children with Atopic Dermatitis.
  
  
  METHODS
  Seventy-two children, aged 2-12 years were selected and followed at the allergy clinic of the Hospital São Zacharias. Skin prick test, specific IgE and food Atopy Patch Test (cow's milk, egg, soy and wheat) were carried out. Three groups were submitted to the Atopy Patch Test: (1) Atopic Dermatitis with or without Rhinitis and Asthma; (2) Rhinitis and or Asthma without AD; (3) Healthy individuals.
  
  
  RESULTS
  In group 1, 40% of the patients presented positive reactions. The longer the exposure time (48h and 72h), the higher the sensitivity. In group 2, the test was more specific than sensitive for all the extracts, with increased sensitivity the longer the time of exposure (72h). In group 3, 8.3% presented positive tests.
  
  
  CONCLUSIONS
  APT evidenced a great diagnostic value in late-phase reactions to food, with high specificity. It showed to be a specific and reliable tool in comparison with the healthy group's results.
authors.affiliation: Allergy Service, Hospital São Zacharias, Botafogo, RJ, Brazil.
authors.forename: Soloni Afra Pires
authors.initials: SA
authors.lastname: Levy
authors.forename: Sergio Duarte
authors.initials: SD
authors.lastname: Dortas Junior
authors.forename: Andrea Huguenim Silva
authors.initials: AH
authors.lastname: Pires
authors.forename: Augusto Tiaqui
authors.initials: AT
authors.lastname: Abe
authors.forename: Solange Oliveira Rodrigues
authors.initials: SO
authors.lastname: Valle
authors.forename: Vilma Perez
authors.initials: VP
authors.lastname: Coelho
authors.forename: Ludwig Ruppert
authors.initials: LR
authors.lastname: Hahnstadt
authors.forename: Alfeu Tavares
authors.initials: AT
authors.lastname: França
mesh_terms: D000485:Allergens / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000209:etiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000175:diagnosis; D006969:Hypersensitivity, Immediate / Q000175:diagnosis; D007073:Immunoglobulin E / Q000032:analysis / Q000097:blood*; D008297:Male; D010328:Patch Tests / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D000485:Allergens; D007073:Immunoglobulin E