Skin as a Metabolic Organ: Dermatologic Markers of Morbid Obesity and Their Role in Risk Stratification and Treatment Monitoring

Morbid obesity is a chronic condition characterized by metabolic disorders and low-grade chronic inflammation, both of which are closely linked to insulin resistance and adipokine dysregulation. In addition to its systemic effects, obesity also leads to structural and functional changes in the skin, supporting its role as an active metabolic and immunological organ. This study analyzed skin lesions occurring in individuals with morbid obesity and explored their potential relevance in the context of metabolic risk and treatment response rather than establishing clinically validated tools. The focus was on how excess adipose tissue affects the skin through metabolic, hormonal and mechanical mechanisms. Although this review focuses on morbid obesity, many of the included studies examine general obesity without separating its severity. Therefore, the findings may not fully reflect patients with BMI ≥ 40 kg/m2 and should be interpreted with caution. Three main areas were considered: the pathophysiological mechanisms underlying obesity-related skin lesions, selected dermatological manifestations as potential markers associated with metabolic risk, and changes in these manifestations during pharmacological, surgical, and lifestyle interventions. Available studies show that acanthosis nigricans and multiple acrochordons are consistently associated with insulin resistance, metabolic syndrome, and metabolic dysfunction-associated steatotic liver disease. An increase in BMI is also associated with impairment of the epidermal barrier, changes in the composition of skin lipids, and modifications of the skin microbiome, while biomechanical factors promote the development of chronic inflammation in the intertriginous areas. It has been shown that normalization of metabolic parameters achieved through GLP-1-based pharmacotherapy, bariatric surgery, or lifestyle changes can improve some skin manifestations, especially acanthosis nigricans. However, it should be emphasized that most available data are based on cross-sectional or observational studies, and validated composite dermatological indices are still unavailable. Skin changes in patients with morbid obesity often reflect underlying metabolic and hormonal disturbances. They may have potential as additional, non-invasive clinical clues, but they should not be treated as independent tools for risk assessment or treatment monitoring. At present, most evidence shows associations only, and it is unclear whether these findings add meaningful predictive value beyond standard metabolic markers. More prospective studies are needed to confirm their clinical usefulness and to define their role in assessing metabolic risk and monitoring treatment over time.