2. Respiratory Allergies
According to the American Academy of Allergy, Asthma and Immunology, hay fever affects about 17.6 million adults and 6.6 million children in the country. Hay fever can trigger asthma attacks and allergic rhinitis, sending thousands of patients to the hospital yearly. The most common causes of respiratory allergies include pollen, cigarette smoke, cockroaches, mold and mildew, pet dander, chemical fumes, and strong scents or odors.