Histopathologic findings of idiopathic trachyonychia: An analysis of 30 adult patients

Abstract Background Trachyonychia, a rare inflammatory disease of the nail matrix, has a more chronic course in adults compared with that in children. However, the histopathologic features of the disease have not been sufficiently reported in the literature. Methods We retrospectively reviewed the pathologic features of idiopathic trachyonychia in adult cases at our center. Results A total of 30 cases were included. The median age was 55.5 years (range, 27‐77 years). Median disease duration was 84 months (range, 8‐384 months). Histopathologic analysis showed upper dermal lymphocytic infiltrates (93.3%), acanthosis (86.7%), exocytosis (63.3%), spongiosis (63.3%), parakeratosis (46.7%), psoriasiform hyperplasia (40%), eosinophilic infiltrates (33.3%), vacuolar degeneration (33.3%), lichenoid pattern (13.3%), Civatte body (6.7%), and collection of neutrophils in the stratum corneum (3.3%). Statistical analysis among pathologic parameters revealed associations of spongiosis with exocytosis ( P < 0.001) and lichenoid infiltration with vacuolar degeneration ( P = 0.008). Three patients (10%) showed fungal co‐infection. Conclusion The majority of cases revealed inflammatory cell infiltration with epidermal changes. Given the inflammation and chronic course of idiopathic trachyonychia in adulthood, active treatment with anti‐inflammatory agents should be considered. Additionally, mycological tests should be considered during initial evaluation as there are cases with fungal coinfection.