Exclusively breastfed infants at risk for false negative double blind placebo controlled milk challenge.

The double blind placebo controlled food challenge (DBPCFC) is the gold standard for diagnosing cow's milk allergy (CMA). However, false-negative DBPCFC have been reported. We present 2 cases with a false negative DBPCFC in exclusively breastfed infants suspected of CMA. These cases highlight the occurrence of severe allergic reactions of infants who were exclusively breastfed. Several reported causes of a false negative DBPCFC will be discussed. However, there is currently no clear understanding of the cause of a false negative DBPCFC. This paper highlights that a negative outcome of a DBFCFC must be interpreted with caution, because a severe allergic reaction might occur upon re-introduction of cow's milk. Therefore, an additional open food challenge under medical supervision is recommended in exclusively breastfed infants with a negative DBPCFC.