Manifestaciones ungueales en enfermedades sistémicas: ¿hechos o anécdotas?

Introduction: Changes in the nails are clinical signs that are easy to detect, but difficult to interpret. The vast majority of these are not pathognomonic of any disease; their pathophysiological background may be common or shared in many diseases. However, in an appropriate clinical context, they can support or suggest the diagnosis of some systemic diseases. Methodology: a narrative review was carried out where an extensive literature search was carried out in databases (PubMed, Scopus, Web of Science), the most up-to-date articles were selected. Approach: This literature review proposes the approach and interpretation of some nail signs in the context of systemic diseases. Alterations of the nail apparatus are divided into 3 large groups; alteration of the matrix including disorders of keratinization and the lamina/bed relationship, evident as changes in the morphology of the lamina; vascular alterations, highlighting the importance of capillaroscopy which has become an important diagnostic tool; and finally the osteoligamentary and perionychium alterations. Conclusion: Although changes in the nails are not a pathognomonic sign of any disease, their presence requires, at a minimum, an exhaustive and systematic interrogation.