Determining What's Biting The feeling of something biting you is often caused by multiple factors including prescription medications. They can also be caused by skin disorders, aging, and allergies. It can lead to nervous disorders, excessive scratching, bleeding and paranoia. People have been known to go to extremes by spending thousands of dollars on pesticides, cleaning agents, etc. and never solving the problem. Others get "crazy" and apply pesticides to their skin and hair. People have also orally ingested pesticides when nothing else works - because they get desperate for a solution. read more