To interpret the situation, I have some queries.
You have not mentioned the age of your son. Was he previously taking milk / dairy products without any complains? Did he has any diarrhoea
episode in recent past or needed antibiotics? Have you changed the milk (brand or type, composition etc) recently? Is there any change in his stool? Is there any other problems like hives, urticaria
, skin rashes?
This could be a case of temporary milk protein allergy
(if he was taking milk products before). The allergic reaction
may cause flushing
of cheeks. In that case, it would be better to keep the child free from dairy products for few days, then re-start slowly. Medicines like pro-biotics / pre-biotics may be necessary if the child had diarrhoea or antibiotics medication in recent past.
If the child was off dairy products for long time (or suggested to do so by doctor), or sensitive to casein (as evident from test) - keep him off milk product.
I would be better for me to analyze the situation if you post with the details.
If the problem persists, or you see any abnormality in your child, go to your Pediatrician
and get your child examined.
Post if you have further queries.