Please say a prayer for my little Collin!

It has been a rough 4 days (and counting) for my little Collin. He woke up crying in pain from a rash all over his body. When I took him to the Doctor that day they confirmed that it was hives. He was so itchy and uncomfortable but was told to take him home and give him Benedryl. Took him home and tried to make him comfortable. It just kept getting worse. By the time the evening rolled around he could hardly walk. I rushed him to ER and they took him back right away. They gave him a steroid treatment and some tylenol. We went home and to my surprise the Hives were remarkably better. Unfortunately, when he woke up again at 2 am they were back in full force. I spent most the morning again trying to make him comfy but nothing helps when you have hives. The welts move all over the body and they itch and hurt according to Collin. The ER doctor mentioned if you start to see the spots change colors to bring him back. Of course, they started to change colors and I knew it was time to visit the ER once again. This time 2 ER docs looked at him and said they thought it was HSP (a form of vasculitis, an inflammation of the blood vessels). He was admitted to the pediatrics floor for more testing. We stayed over night and allowed them to draw blood (not fun) only to have them come back and say it's Hives. I am getting Collin ready to go home and the poor boy can't walk. His little knees are so swollen you can see bruising. He cries when you slightly touch his legs. They say this can last for another week. Now, I must go home and hope I don't feed him what caused this allergic reaction. I would give anything to take this away from my sweet little boy. He only wants to have a good time and he is confined to the couch indefinitely. So, while not life threatening it is so horrible to see him like this. Please Pray for Collin!