These microorganisms thrive in domestic environments. Dust mites, for example, are microscopic creatures that feed on our dead skin cells and lodge themselves deep within mattresses, pillows, carpets, and upholstery. What causes the allergic reaction is not the mite itself, but its droppings. Similarly, pollen enters through windows and settles on every surface, while moisture in bathrooms and kitchens can create mold colonies that release spores into the air.