ABSTRACT
BACKGROUND: The food atopy patch (APT) test has been used in previous studies to help the diagnosis of non-IgE mediated food allergies (FA). The aim of this study was to evaluate the efficacy of different cow's milk APT preparations to predict oral tolerance in children with previous non-IgE-mediated cow's milk allergy (CMA) diagnosis. METHODS: Thirty-two patients non-IgE-mediated CMA diagnosed by oral food challenge (OFC) were enrolled to perform APT with three different cow's milk preparations (fresh, 2% in saline solution, 2% in petrolatum) and comparing with a new OFC after at least three months of diet exclusion. RESULTS: Only six (18.7%) subjects presented positive OFC to cow's milk. No differences in gender, onset symptoms age, OFC age, Z-score, and exclusion period were found between positive and negative OFC patients. Preparations using fresh milk and powdered milk in petrolatum presented sensitivity equal to zero and specificity 92.3% and 96.1%. The preparation using powdered milk in saline solution showed sensitivity and specificity of 33.3% and 96.1%. Two patients presented typical IgE symptoms after OFC. CONCLUSION: Cow's milk APT presented a low efficacy to predict tolerance in patients with previous non-IgE-mediated CMA and should not be used in clinical routine. The presence of typical IgE reactions after OFC hallmark the necessity of previous IgE-mediated investigation for this patient group.
Subject(s)
Milk Hypersensitivity/diagnosis , Patch Tests/methods , Allergens/administration & dosage , Allergens/immunology , Animals , Cattle , Child, Preschool , Female , Humans , Immune Tolerance/immunology , Infant , Male , Milk Proteins/administration & dosage , Milk Proteins/immunology , Sensitivity and SpecificityABSTRACT
BACKGROUND: Food allergy is an increasing problem in public health, especially in childhood. Its incidence has increased in the last decade. Despite this, estimates of the actual incidence and prevalence are uncertain. The aim of this study was to estimate the prevalence of food allergy in infants and pre-schoolers. METHODS: The parents of 3897 children completed questionnaires on the occurrence of any reaction to food. Children with parentally reported reactions were selected for further examination including a clinical interview, physical examination, allergic tests, and if necessary, oral food challenge to conclude the diagnosis of FA. RESULTS: The estimated prevalence of allergy in children aged 4-59 months was 0.61%, being, 1.9% in infants and 0.4% in pre-schoolers. Among the 604 patients physicians evaluated with parent-reported FA, 24 (4%) had a confirmed diagnosis of food allergy, and 580 (96%) were excluded in the remaining. Of these, approximately half (51/52.6%) of 97 infants and (128/48%) of 487 pre-schoolers already performed the diet exclusion suspected food for a period of time. CONCLUSION: This study shows that high overall prevalence of parental belief of current food allergy however the same was not observed in the in physician-diagnosed food allergy. The prevalence of food allergy was lower than that observed in the literature. This study alerts health professionals to the risk entailed by overestimation of cases of food allergy and unnecessary dietary exclusion, which may result in impairment in growth and development of children, especially in their first years of life.