Mosquito Bites?

Last week Livi and I were at the playground and the next day I noticed that she had several mosquito bites on her legs. Other than the fact that I could tell they would itch her once in a while I didn't think much of them. They were almost completely gone and then yesterday and today they have all of sudden swelled up into these odd rings. I took her to the Dr today because I had no idea what it could be. He was pretty surprised by them and still isn't sure what they are. He is assuming that it's a delayed secondary reaction to the mosquito bites so he prescribed some steroid cream. If that doesn't work then he is thinking maybe it's ring worm. Crazy. Aside from the irritation they obviously cause her, it's so sweet how she tries to kiss them better.