Acquired perforating dermatosis: A clinicopathologic study, and the features of dermoscopy and reflective confocal microscopy of 37 cases

BACKGROUND: Acquired perforating dermatosis (APD) is a rare skin condition characterized by degenerated materials eliminated from the dermis. Several retrospective studies on APD have been reported; however, few data are available on Chinese APD and their features on dermoscopy and reflective confocal microscope (RCM) assays. OBJECTIVE: The aim of this study was to retrospectively evaluate the clinical and histopathologic data of 37 acquired perforating dermatosis cases, and assess their features on dermoscopy and RCM. METHODS: Thirty‐seven APD patients were retrospectively enrolled in our study. We characterized the clinical histopathological features, concomitant diseases, treatment responses, and the dermoscopy and RCM findings. RESULTS: Pruritus was the most common symptom, with the lower extremities as the most predilection sites (86.5%, n = 32; 91.9%, n = 34, respectively). Concomitant diseases were found in 34 patients (92.6%), among which diabetes mellitus was the most common, followed by thyroid nodules, allergic dermatosis, and chronic renal insufficiency. Dermoscopy and RCM assays were performed in 11 patients. The typical RCM images were hyperreflective cord‐like structures from the epidermis to dermis. Dermoscopy features of fully developed lesions showed central ulceration with peripheral hairpin‐like or loop‐like capillaries with characteristic garland arrangements. CONCLUSION: APD is an uncommon skin disorder associated with various systemic conditions in Chinese individuals. Thyroid disorders are an overlooked complication and may play an important role in the development of APD. The results of this study indicate that noninvasive dermoscopy and RCM examination are helpful in the rapid diagnosis and early intervention of APD.