Serum Granulysin Levels in Vitiligo and Alopecia Areata: A Potential Biomarker for Disease Activity and Dermoscopic Evaluation

<b>Background:</b> Vitiligo is a chronic, progressive skin disorder characterized by the development of sharply demarcated depigmented patches due to the loss of melanocytes. Alopecia areata (AA) is an autoimmune condition that presents with sudden, non-scarring hair loss affecting the scalp or other body areas. <b>Objective:</b> To evaluate serum granulysin (GNLY) levels in patients with vitiligo and AA to explore its potential role in the pathogenesis and activity of both diseases. <b>Methods:</b> A total of 80 participants were included: 65 patients and 15 healthy controls. Patients were divided into four groups: active vitiligo (n = 25), stable vitiligo (n = 25), active AA (n = 15), and a control group (n = 15). Serum GNLY levels were measured and analyzed in relation to clinical and dermoscopic features. <b>Results:</b> No significant correlation was found between GNLY levels and either age or Vitiligo Area Scoring Index in vitiligo patients. However, serum GNLY levels showed a significant association with the Vitiligo Disease Activity score. GNLY levels did not correlate with sex or the starburst pattern. In contrast, significant associations were found between elevated GNLY levels and dermoscopic signs of activity, including ill-defined lesion borders, satellite lesions, perifollicular pigmentation, and loss of pigment network. Both vitiligo and AA patients exhibited significantly higher GNLY levels than controls, with the highest concentrations observed in the active vitiligo group. <b>Conclusions:</b> The significant rise in serum GNLY levels in vitiligo and AA suggests a pathogenic role, with higher levels in active vitiligo indicating its potential utility as a biomarker for monitoring disease activity.