Association Between Periostin Expression and Disease Progression in Lichen Planopilaris: Insights Into Pathophysiology

Introduction: Lichen planopilaris (LPP) is the most prevalent form of scarring alopecia and lymphocytic infiltration that affects the infundibulum and isthmus, perifollicular melanophages, and perifollicular constrictive fibrosis Objective: We aimed to assess the contribution of periostin tissue levels to the pathogenesis of LPP and its association with disease severity. Methods: A total of 30 cases diagnosed with LPP between July 15 and October 15, 2022 were studied. Patient age, disease duration, disease severity, and periostin levels were recorded, and periostin immunohistochemistry was performed to obtain histoscores for the perifollicular area, dermoepidermal junction, fibroblasts, and inflammatory cells, and these were compared with the control group. Results: The female sex predominated, with the majority (67%); 25 patients were classified with mild disease and five with severe LPP. Statistically significant differences were found in keratinocyte staining intensities between the mild and severe groups (P=0.023; P<0.01), with the LPP group exhibiting a higher rate of moderate staining intensity compared to the control group. In terms of perifollicular staining intensities, the rate of non-staining was higher in the control group compared to the LPP group. Statistically significant differences were also observed in fibroblast (P=0.001) and inflammatory cell (P=0.001) staining intensities between the groups. No statistically significant difference was found between the patients with mild or severe disease in the LPP group. Conclusion: The relationship between periostin and disease severity could not be conclusively established. The presence of periostin staining in all histopathologically-affected areas of patients with LPP suggests that periostin may serve as a promising marker in LPP.