With the push to whole grains, raw vs cooked, etc for feeding it is something that is going to become more common an issue since it is a shock to the system. Kids that lived on special infant cereals and purred food - generally cooked before puree they are suddenly as toddlers switched to a new diet. Corn doesn't even digest in some adults. If possible serving the foods cooked or mixed with other foods such as a fruit berry mix rather than a whole dish of blueberries would help.

For the rash you will need to use a zinc cream at every change because once the rashses start the skin actually thins and then repeat rashes are more common. Sudocrem, the one by aveeno are good ones. Desitin used to be good in it's old formulation and so did peneten but don't like the new one of either for ideal healing. the aveeno diaper cream is recommended for those with eczema.