Will a dog door give my pet a headache? Most pets push their dog door or cat door open with their heads, but the doors open so easily they won’t get headaches. If a pet door were to cause a pet pain, they would be unlikely to use it. Flap doors are often made from a flexible vinyl and open easily when a pet pushes their head against the flap. Many cat doors have an acrylic flap and these too open easily. The PlexiDors have hard panels, but they swing open so easily that even small pets can use a very large door. A thing to consider may be that extra large flap doors have very heavy flaps, and a small pet might not be able to open them. Some pet owners also worry about their pet running head-first into a locked door. If this is a cause of concern it can be a good idea to attach the security plate when the door is locked, to signal that they can’t get out.