What are the three phases of extrinsic asthma

Early ( 15 minutes ) --> cross linkages of two IgE on mast cells causing degranulation Late ( 4 hours ) --> After recovery from mediators from mast cells, then activation of macrophages and chemotaxis and eosinophils into the lining of the bronchi Prolonged hypersenstivity ( days ) --> Exaggerated response of airway after exposure , inflammatory cells in the bronchial walls continue giving loss of epithelial cells