I have experienced my ds sleeping better after we removed allergens, as well as experiencing a growth spurt. Now we know when he has eaten an allergen in that he doesn't sleep well and he is also more aggressive.
The flushing of the cheeks IS a signal of an allergen... as well as lots of other things... Like soft squishy or multiple poops in one day, and a red sunburn looking around the anus.
From what I know, it seems like your daughter wouldn't necessarily have the same symptoms as your dh... but it's very important that you keep watching her for signs of allergies because it's very likely she has them... so you could keep them from becoming severe perhaps.
Many people do elimination diets to try to find out for themselves what it is that your baby is responding to. Generally, they say there are 6? foods that cause a majority of the allergies... those are Dairy, Eggs, Wheat, Soy, and ??, ?? Try eliminating these things one at a time and seeing if there is a difference. It could take up to a week to notice a difference... If after a period of time you don't see a clear difference you may want to consider that there is more than one allergy. If you have the resources, you might consider seeing a pediatric allergist.
We found ds had several allergies, including one to garlic.
I have more resources if you're wanting more feel free to pM me.