If you have a house dust mite (HDM) allergy, you might be allergic to the microscopic bugs themselves— it’s common for people to be allergic to their exoskeletons in some cases. More likely though, you’re reacting to a potent enzyme in their droppings. Keeping those droppings (and dead bug bodies) away from your lungs, nose and eyes is the purpose of allergy encasements. It’s very easy to breath these microscopic particles in when you make these airborne from any movement of your bedding, After touching an non-encased mattress it’s also very simple to rub these enzymes in your eyes creating an almost instant cause of symptoms. Mattress and Pillow encasements have been proven to work straight away and are effective in assisting to prevent allergic diseases such as eczema, rhinitis and asthma from taking root in people genetically-predisposed to those conditions.