 [ Symptoms ] does keflex reduce milk supply during breastfeeding [ Disease ] first off whey typically contains low levels of casein but it is obviously present in the milk children can outgrow food allergies so you want to see a board certified pediatric allergist on a regular basis and keep himher updated on changes in your child you also want to make sure food allergy diagnosis utilize a combination of tests skin prick blood test food elimination etc  so you get an accurate reading the best thing to do is to visit a pediatric allergist to see if your child is still allergic to casein he or she can help you decide whether or not to start introducing products that your child has previously had reactions to good luck