Asthma is a chronic lung disease characterized by airway inflammation, obstruction due to muscle spasm, and mucosal edema caused by hypersensitivity to irritants. It is caused by both genetic and environmental factors like allergens, infections, climate, diet, pollutants, and drugs. Symptoms include dyspnea, wheezing, and cough. Diagnosis is based on patient history and examination. Treatment involves quick relievers for acute attacks and preventers like steroids to control inflammation and prevent further attacks. Nursing management focuses on education, environmental control, evaluation, emotional support, and regular follow-up.