Abstract: 【Abstract】 Objective To summarize clinical manifestations and histopathological features of granular parakeratosis （GP） after exposure to benzalkonium chloride. Methods A retrospective analysis was performed on 7 GP cases with a history of benzalkonium chloride exposure in the Department of Dermatology at Wuhan No.1 Hospital from April to August 2022. Data were collected on the general condition, skin lesion manifestations, pathological examination, treatment, and follow-up of the patients, and retrospectively analyzed. Results The 7 adult patients with GP typically presented with erythema and brown scales in the intertriginous area, exhibiting an annular distribution pattern. All the 7 patients reported recent exposure to disinfectants containing benzalkonium chloride. A total of 10 skin biopsies were taken from the 7 patients. Histopathological examination showed characteristic hyperkeratosis and fine blue-gray parakeratotic granules in the stratum corneum. All skin lesions improved 1 month after cessation of exposure to benzalkonium chloride. Conclusion GP has a distinct clinical pattern and histopathological manifestations, and a history of exposure to benzalkonium chloride can be helpful for the diagnosis of GP.

Key words: Granular parakeratosis, Benzalkonium chloride, Clinical manifestation, Histopathological manifestations