Child Having Swollen Ears. Reason?

I was called by my daughters nursery today to pick her up as both of her ears are swollen. She is 3 years old, I got to the nursery and they were swollen a lot, both of them. I took her to a&e to be told Maybe an allergic reaction and sent home, she has not eaten anything different today than she usually does and I was really not happy with the outcome. She had Piriton and they didnt really go down much, still swollen now. Please Help x