Question- Why would store bought grape juice cause my sons eczema to flare up but not store bought organge juice.

Hello,
My husband and I have been eliminating things from my sons diet to help his eczema. It involves keeping a food diary and we notice that after having some things in particular he would flare up that night or even the next day. We noticed this with grape juice so we eliminated it and his skin got better. However this week my husband got some free safeway organge juice on his club card. Its some kind of promotion that they are doing for safeway customers. Well he got the free OJ and its just the generic brand but it is 100% juice (store bought). Well he has been giving it to Jacob every day this week with no flare ups. He does put cod liver oil in it from time to time, but not always.

Well my question is if the Sugar can cause flare ups then why would he be okay with store bought organice juice but store bought grape juice causes flare ups??? This is a puzzle to me? Any ideas? I thought the sugars were the same.

Sarah Tweet