Information is essential in all fields, including medicine. In research, epidemiology, prevention, and health care management, the information we work with must be correctly classified.

In particular, information on diagnoses must be recorded and classified uniformly and accurately to ensure common practice among all health professionals over time. Because the number of known diseases is so enormous—and constantly increasing, thanks to medical advances in technology and research—this is not as simple as it may seem at first glance.

The International Classification of Diseases (ICD), in its various versions, is the most widely used system for diagnostic coding. The 10th and current revision of the ICD (ICD-10) has recently been criticized for not including certain diagnoses. In dermatology, an ICD adaptation developed in Spanish years ago attempted to solve this problem.1 Given this background, it is necessary to analyze the inaccuracies and coding-related difficulties associated with the dermatologic diagnoses included in the ICD-10, with a view to achieving a better classification in the ICD-11.

In this study, carried out in the context of outpatient dermatology care in Spain, the authors conducted an agile and well-designed analysis of the causes of these difficulties and identified those which arise from deficiencies in the ICD-10 that may or may not have been rectified in the draft version of the ICD-11.2 The authors concluded that the ICD-10 and the ICD-11 draft are both valid but not free of deficiencies, especially with regard to the inclusion of diagnoses discovered or developed in recent years. Nevertheless, the ICD-11 draft does include some improvements that were identified in this study.

In conclusion, this study underscores the need for constant vigilance and ongoing improvement in disease classification, particularly in dermatology.