Erosive palmoplantar lichen planus: clinical and histopathological insights from an ethnic population of North-East India

Objectives: Palmoplantar lichen planus (LP) is an uncommon disorder often posing a diagnostic dilemma, particularly in the absence of characteristic LP lesions elsewhere in the body, but also because of its varied atypical presentations. The erosive variant of palmoplantar LP is an even rarer entity that has been described only in small case reports. Therefore, this study aimed to describe the clinico-pathological spectrum of this variant of palmoplantar LP. Methods: A retrospective study was conducted in a tertiary care hospital in North East India from 2013-2023, where records of all cases diagnosed as erosive palmoplantar LP were included for descriptive analysis. Results: A total of 16 patients were included, including seven females and nine males with a median age of 15 years (interquartile range: 12-30), with a predominance of pediatric patients (n = 10; 62.5%). All patients had plantar involvement, half had nail involvement, and only 2 patients (12.5%) had typical LP lesions elsewhere, but with no mucosal lesions or scarring alopecia. Histopathological findings included band like inflammatory infiltrate at the dermo-epidermal junction and basal cell degeneration, respectively, in 100% (n = 16) and 93.75% (n = 15) of the cases. Conclusion: This study presents the largest number of patients with a clinico-histopathological diagnosis of erosive plantar LP particularly from a single indigenous tribal population in North East India, with a male and pediatric preponderance, for which we have no explanation.