What Causes Large Bumps On Body?

What kind of bug causes large bumps? My niece woke one morning with a few huge bumps in random places but it didn't start happening until construction started in the roof. She wiping dust from a window seal and has bitten ever since. We've changes sheets and clothes and everything else. There is also another bed in her room and nothing has happened on that side. I've only experienced large bites like that from Mosquitos but there are none in NYC right now it's too cold. Please help