People who are allergic to dust are actually allergic to one or more of the components of dust. Although you can't see any of them with the naked eye, dust mites, cockroach pieces, fungus and animal dander are the most likely culprits. Dust mites are miniscule eight-legged insects that eat shed skin particles, and they're the most common allergen within dust. However, the symptoms of a dust allergy are the same regardless of which allergen is your personal trigger. Since you mainly come in contact with dust by breathing it in, most symptoms affect your nasal passages, which become inflamed. You end up sneezing and coughing, with a runny nose; itchy, red eyes; congestion; an itchy nose, mouth or throat; a postnasal drip; and sinus pressure. Some people develop dark skin below their eyes and they have trouble sleeping because of their allergies. Dust allergies can also trigger asthma attacks in people with asthma.