My oldest daughter,now 8, had many food allergies as a toddler,sometimes it would show as a rash around her mouth or runny poop then causing a tooshie rash but like your daughter she once too had a rash all over her, it looked like hives, it took me forever to figure out what the allergy was from, especially since I made all of her food fresh. In the end it ended up being raw tomato beleive it or not. I have a deck garden every year and being Sicilian/Italian tomato is a staple,she would help me garden and then eat some cherry tomatos. Apparently the acid in it was too much for her little body and thus broke out. As an 8yr old she seems to be fine with it, alot of times they out grow these things too. Sometimes it's an allergy to preservatives if it's store bought food,she at one time had an allergic reaction to grape juice but not grapes,cow milk but not yogurt,canned or pre packaged fruit but not fresh. I've also seen children have an adverse reaction to red dyes in juice or jello or to the horrimones is chicken,whole milk or even soy products. She was even once allergic to sweet potato, weird right? Who knows why,it'll just take some det. work. As for soothing her itchies, my big girl also suffers from excema(very dry itchy skin) and what helps her is...soaps without dyes or perfumes and moisturizing saops such as olive oil soap or oatmeal bars,also most supermarkets or drug stores will have a collodial oatmeal bath. After baths pat her dry instead of rub and put a dye/perfume free lotion on her, many recomend Eucerin in the tub form because it's thicker,some love Weleda products or anything with,aloe,vit E,shea or cocoa butter,oatmeal or olive oil in it. I put some on her every night especially in the fall/winter season. Is it possible that she has excema? If not these things will help for any itchies no matter the cause,even chicken pox. Hope this helps, hang in there. J.