Asthma is a chronic inflammatory disease of the airways characterized by recurrent attacks of wheezing, shortness of breath, chest tightness, and cough. There are two major subtypes - atopic asthma associated with environmental allergens and a family history of atopy, and non-atopic asthma associated with viral infections and air pollutants. Occupational asthma can be caused by repeated exposure to fumes, dusts or chemicals. Pathogenesis involves a Th2 immune response leading to IgE production, eosinophil recruitment, and airway inflammation. Genetic and environmental factors contribute to susceptibility. Asthma triggers both early and late phase responses characterized by bronchoconstriction, mucus production, and leuk