Well actually the itching seriously happens the next day after being bit. Jeepers I hope you figure this out quickly..They get me just outside sometimes too, but seem to be coming from the chicken barn mostly. I've had them get in my car, I think I tracked them in on my shoes or clothes...and spraying my car with Lysol fixed it. I've also had them attracted to the light on my cell phone and computer screen in the house!! And they bite my hands and face when I'm on one of these devices...like right now. I think I tracked them in yesterday, which was when I posted this because I'm freaking out from the itching!!