One sign that you’re infested with lice is itchiness. While this can be an uncomfortable symptom, its actually only present in about half of the people who are infested.Many people assume that lice itch is caused by the bugs crawling around, but its actually caused by a reaction to the bites.Just like with mosquito bites, some people react strongly while others don’t react at all. This along with the severity of itchiness varies from person to person.