What Causes Random Swollen And Itchy Spots On A Teenager's Body?

My 14 year old daughter for the last two weeks has random swelling happening. It causes her no real distress other than occasionally painful at the swelling spot and itchy. First it was just her bottom lip, then just her top lip(only on one side) then only her baby finger on one hand. This morning it is her baby finger on both hands as well as one thumb and part of the palm of one hand. She is claiming no other symptoms bother her.