In neonatology, diaper rash in premature babies under 37 weeks of amenorrhea is a frequent occurrence. The lack of definition and homogeneity of practices around this subject, and the call for tenders from the Auvergne-Rhône-Alpes region's inter-regional grouping for clinical research and innovation, motivated teams from the Annecy-Geneva hospital center to become promoters of a paramedical research project, Califesse. The study was divided into two stages: the first to create a visual scale, the second to carry out an epidemiological description of diaper rash and to propose a reference framework.