The skin of a patient is the first and most visible structure of the body that any health-care worker encounters during the course of an examination. To the patient, it is also highly visible, and any disease that affects it is noticeable and will have an impact on personal and social well-being. The skin is therefore an important entry point for both diagnosis and management. Many diseases of humans are associated with changes to the skin, ranging from symptoms such as itching to changes in colour, feel and appearance. The major neglected tropical diseases (NTDs) frequently produce such changes in the skin, re-enforcing the feelings of isolation and stigmatization experienced by patients affected by these diseases. This app explains how to identify the signs and symptoms of neglected tropical diseases of the skin through their visible characteristics. It also contains information on how to diagnose common skin problems that front-line health workers may encounter.