Abstract: Asthma is a chronic heterogeneous inflammatory disorder/syndrome of the airways that affects more than 300 Million people worldwide. Asthma often starts in childhood (Allergic Asthma phenotype).Co morbidities often trigger asthma exacerbations. It’s often difficult to diagnose asthma in young children. Objective tests of lung function aid in the diagnosis of asthma in children > six years of age. Asthma has phenotypes and endotypes. Biomarkers Ex. Fractional excretion of Nitric Oxide aid in the diagnosis of severe asthma in children and adults. Management of Severe Asthma has undergone a revolution. Asthma is responsible for considerable global morbidity and health-care costs. Substantial progress was made against key outcomes such as hospital admissions with asthma and mortality in the 1990s and early 2000s, but little improvement has been observed in the past 10 years, despite escalating treatment costs.