why is it my kid breaks out in the most red and bumpy rash on her cheeks and i take her to 4…

why is it my kid breaks out in the most red and bumpy rash on her cheeks and i take her to 4 pediatricians and they are all stumped, then my house mates baby nurse that comes here takes one look at my kid and casually mentions it looks like eczema and to try aquaphor and 2 days later its almost gone? wtf?!