It's true! In addition to mold, animal dander, dust mites and cigarette smoke, cockroaches make the list of the most common indoor allergens. Exposure to cockroaches' cast-off skins and airborne roach residue can trigger a response in 80% of those with asthmatic sensitivity. Infants who have prolonged exposure to roach residue are more likely to remain sensitive to cockroaches for the rest of their lives. Children and adults who already suffer from asthma can see their medical condition worsen with repeated exposure. Cockroaches are one of the hardest allergen triggers to eliminate because they are such a pest.