when will food allergy show up when intro new food?

[angie&lane]

When I start a new food (same one for 1 week), after which point is it safe to assume reactions are not from an allergy?  For example, my 6 mo old has eaten squash for 5 days with no reaction, then today he has a hard time pooping and his bottom is a little red and sensitive (not too bad).  His poops are pretty hard, too.  Does it sound more like constipation than an allergy??  If so, which foods are common for causing constipation?  I'm wondering if I'm feeding him too much rice cereal (about 3 tbsp twice a day along with a fruit or veggie).  Maybe I should switch to cereal only once a day and doing just the fruit or veggie at the other feed.  Any ideas?
Thanks,
Angie

[Sharon P]

i am wondering the same thing, so i look forward to reading any responses.

sharon.

[Mom to M&M]

Squash and rice cereal can both be constipating, especially the rice. I'd definitely cut back on the rice cereal and/or switch to another grain (oatmeal and barley are less constipating) and see if that helps.