A 23-year-old African Caribbean woman presents in the emergency department with an acute onset facial rash. During initial assessment she complains of a two week history of general malaise, fatigue, fever, and weight loss. You have been assigned her examination…100 Cases in Dermatology presents 100 scenarios with a dermatological manifestation commonly seen by medical students and junior doctors. A succinct summary of the patient’s history, examination and initial investigations, including full colour images showing presentation, is followed by questions on the diagnosis and management of each case. The answer includes a detailed discussion on each topic, with further illustration where appropriate, providing an essential revision aid as well as a practical guide for students and junior doctors.Making clinical decisions and choosing the best course of action is one of the most challenging and difficult parts of training to become a doctor. These cases will teach students and junior doctors to recognize important dermatological symptoms and signs and, where appropriate, their relationship to other medical conditions, and to develop their diagnostic and management skills.