My granddaughter came home with tiny bumps on her legs and bottom. The first day they are very red and the next they are partially gone? She was taken to pediatrician and blood work & Urine were tested and all were negative she was referred to dermatologist. The following day she returned home with what looked like hives on her other leg. Some were dime size and some larger. The dermatologist did a biopsy yesterday. What could this be? She is only 5 and in kindergarten.