If you are finding lots of mysterious bites in the last two weeks during the warmer months, one possibility could be bird mites. These creatures look like walking pepper grains and would prefer to feed on birds. As the young birds leave the nest we often get them migrating into homes. They do not live for more than a few days but they will bite people and cause reactions. They can not breed on people and do not live on the skin. They can not survive for very long off of their bird host and can not survive in modern homes for very long. The best control is to find and dispose of the nest – which is the source of the problem.
Unfortunately, there is a lot of poor, unreliable, and downright incorrect information on the internet. Several reliable sources of information are available through universities, such as this factsheet from Penn State University.