What Causes Welts On Different Parts Of The Body?

Hello. My nine year old daughter keeps developing these welts on different sections of her body. Yesterday she had one on her right wrist. This morning, I found a large welt on her torso on the left side. Tonight, she complained about discomfort in her groin area... In the crease between her thigh and her private parts. At first I thought they might be bites of some sort, but they look more like hives. She hasn't eaten anything out of the ordinary... Please help.