My Family Is Experiencing Itching And What Appears To Be

My family is experiencing itching and what appears to be small bites in our home. It's not bed bugs and we have no pets. Sometimes it feels like something is crawling on our skin. The red spots are very small but itch like crazy. The old bites never seem to go away and new ones appear. Some days it doesn't seem to itch but the times are getting more often. Do you have any idea what could cause this?