Many individuals have immune systems that react to harmless substances such as pollen and dust. It has been documented that cockroaches trigger allergic responses in around 12% of the population with no other allergies. Roughly 33% of individuals that are sensitive to other allergens also experience allergic reactions due to cockroaches. Sensitive individuals may be triggered to have allergic reactions when exposed to cockroach feces, salvia, dead bodies, and molted skins. These allergens may become particulate and airborne within the home, potentially irritating the respiratory systems of people who live in or visit the home. Allergic reactions as the result of cockroach exposure may manifest as sinus congestion, rash, sore throat, and eye irritation. If allergic symptoms are experienced year round, this may be indicative of cockroach infestation given that most allergies are seasonal. Additionally, allergic reactions to cockroaches may aggravate asthma conditions in susceptible asthmatics.