Is Ara h 2 indeed the best predictor for peanut allergy in Dutch children?

BACKGROUND: Specific immunoglobulin E to Ara h 2 (sIgE to Ara h 2) is described as an upcoming predicting factor for diagnosing peanut allergy in children. The gold standard for diagnosing peanut allergy is a double blind placebo controlled food challenge, however this is time consuming and potentially harmful. We investigate Ara h 2 as a preliminary less invasive diagnostic tool for diagnosing peanut allergy in a general population of peanut sensitized children. METHODS: Children (n=52) with peanut sensitization were retrospectively included. An oral food challenge (OFC) confirmed peanut allergy or tolerance, as primary outcome. Individual candidate predictors were identified by univariate regression analysis and used in a prediction model. Different cut-off values were obtained and receiver operating characteristic curves were plotted. RESULTS: Multivariate analyses resulted in Ara h 2 as best predictor, with a discriminative ability of 0.87 (95% confidence interval, 0.77-0.97). Sensitivity and specificity of 55% and 95%, respectively, were found for a sIgE to Ara h 2 cut-off value of 4.25 kU/L. The highest positive predictive value of 100% was reached at 5.61 kU/L. No absolute relation was found between the value of Ara h 2 and the severity of the reaction during OFC. CONCLUSION: This study developed a prediction model in which sIgE to Ara h 2 was the best predictor for peanut allergy in sensitized children in a general hospital. Therefore depending on the history and the Ara h 2 results, an OFC is not always needed to confirm the diagnosis.

[An acute vomiting infant with profuse diarrhoea: enterocolitis due to non-IgE-mediated cow's milk allergy]. / Een hevig spugende zuigeling met profuse diarree: enterocolitis door niet-IgE-gemedieerde koemelkallergie.

BACKGROUND: Food protein-induced enterocolitis is a manifestation of non-IgE-mediated cow's milk allergy, characterized by acute vomiting and profuse diarrhoea. This reaction is often not recognized as cow's milk allergy. CASE DESCRIPTION: We present a 6-week-old, formula-fed girl with frequent vomiting, diarrhoea and failure to thrive. These symptoms disappeared after giving cow's milk-free formula. Forty-five minutes after the last dose in a non-blinded provocation test with cow's milk, she developed profuse diarrhoea and vomiting, resulting in hypovolemic shock. No specific IgE against cow's milk was found. CONCLUSION: Unusual in this case is the severe but relatively late reaction to the provocation test. In an acutely ill infant with vomiting, diarrhoea and pallor - which can even result in shock - food protein-induced enterocolitis as manifestation of non-IgE-mediated allergy must be considered. These symptoms start as late as 2 to 3 hours after exposure and disappear after withdrawal of the causal product.