My son woke up about a month ago with these tiny mosquito like bumps all over his arm. I called Terminex and Orkin. They both came out and inspected. They found no sign of anything in his room or mine. A few weeks ago I woke up with some very itchy mosquito bumps on my arm... around 5 of them. I scratched them until they swell up. Still nothing was found. I captured a bug crawling across my bed and I called both companies back. They both agreed that it wasn't a bed bug.. it was a carpet beetle and they don't bite. What could it be?? I do have a cat; she doesn't go outside or interact with other animals so I'm guessing the culprit can't be fleas.

It only takes a couple mosquitoes to do that loose in the house... and they can be hard to find. Depending on where you live it might be that time of year for them.

Could be spider bites of an unknown tiny variety. Fleas, mites, etc... DO keep looking however. You will stand a better chance of finding something sooner if you do.

This happens only in case of mosquitoes..

Mosquito's aren't the only insects that bite. Or can be found in a home... or raise those sorts of welts. Any bug that bites can do it. And some are very hard to find.