Book excerpt: This resource guides prescribers, pharmacists, and regulators with an update on the recent expansion of basic and clinical knowledge that forms a framework for understanding cutaneous reactions. This understanding will lead, in turn, to better outcomes and decisions in treatment and management, both in the clinic and in the life cycle of drug development. The skin is a common target for adverse drug events and even mild rashes can be part of life-threatening syndromes. Patients and practitioners often face important decisions about therapy after a drug eruption, including treatment, cross-reactivity with future pharmaceuticals, genetic considerations and dealing with long-term sequelae after a reaction. An international team of experts and leaders in the field share their story and insights into the scientific details and relevant clinical context.