Asthma is a chronic lung disease of variable severity in which the lining of the lungs becomes inflamed and swollen with excess mucus production causing coughing, wheezing, and shortness of breath. Currently it is estimated that approximately 25 million Americans have asthma. Asthma triggers include allergens, viral infections and sinusitis, exercise, certain weather conditions such as cold air and temperature change, exposure to irritants, and gastroesophageal reflux. Thorough medical history, physical examination, lung function testing and allergy skin testing are commonly employed in diagnosing asthma and determining triggers. Treatment includes avoidance of triggering exposures, medications and close monitoring and follow-up. Allergen immunotherapy for allergic asthma and Xolair administration for severe asthma are considerations.