I am trying to figure out what is causing my son's skin rash. It started on his right forearm as a few bumps. The next the bumps swellwed together making a half moon shape. 5 days later he had a bunch of bumps on his stomach that looked like bug bites. Then the next day they all swelled together and created a half moon (circle) shape too. He also started a non-bumpy rash all over his shoulders, back, chest & face. I took him to the doctor's and they said that these two rashes were completed unrelated. The one that came later on his shoulders & face they said was fifth disease (which has been going around his school) but the "bad" one on his stomach & forearms they didn't seem to really know what it was. They told me to just give him allergy med, oatmeal baths & put calamine lotion on it for comfort and that he probably just touched something that he is allergic to. Doesn't sound right to me since the rash has such a distinct shape all over. Please help!