Both children have a rash on them this evening. Started with 9 yr old under her arms, now her chest and back as well. Began approx 4 days ago. This evening found same thing on 3 yr old. tiny, fine red bumps that itch but not severely. We took a little vacation over the weekend and I used a knock off dryer sheet brand while their. I am inclined to think its an allergic reaction but the fact one started first with it and now the other presents. They have not had skin reactions to my knowledge before from detergents. Should I be concerned? Little one has has had a bit of an on and off belly issue as well for the last several days. Thanks!