Asthma is a chronic, reversible obstructive airway disease characterized by airway inflammation, bronchospasm, and mucus hypersecretion. It is one of the most common chronic diseases in the United States, affecting both children and adults. Importantly, most asthma deaths are preventable — they result from delayed treatment, underestimation of attack severity, and under-use of inhaled corticosteroids for long-term control. The key feature is reversibility. Unlike chronic obstructive pulmonary disease (COPD), the airway obstruction of asthma is largely or completely reversible with bronchodilator treatment. Post-bronchodilator spirometry showing an improvement in FEV1 of at least 12 percent helps confirm the diagnosis. Asthma is broadly divided into two overlapping patterns: - Extrinsic (allergic) asthma: the most common form, triggered by allergens such as pollen, dust mites, animal dander, and mold. It is IgE-mediated, with early-phase and late-phase reactions, and often begins in childhood with a family history of atopy. - Intrinsic (non-allergic) asthma: triggered by cold air, exercise, viral respiratory infections, NSAIDs or aspirin (aspirin-exacerbated respiratory disease), occupational exposures, gastroesophageal reflux, and emotional stress. For the NCLEX-RN, your priorities are to grade attack severity...