In the era of personalised medicine, approaches to asthma assessment and management have shifted significantly. Asthma is no longer viewed as a homogeneous disease; rather, it arises from multiple biological processes with complex inter-relationships with other diseases. This conceptual shift renders difficult and severe asthma highly tractable therapeutically. Effective management therefore relies on the identification and management of these processes. This review discusses these treatable traits in asthma, their pathology, diagnosis and management, providing a structured approach for the holistic care of patients with severe asthma. Current evidence gaps are surveyed and future avenues for targeted treatment are highlighted.