Dermoscopy of acquired perforating dermatosis demonstrating three-zone concentric pattern, white-collar sign, focal red dots, and hairpin vessels

A 57-year-old man developed multiple pruritic, follicular, and nonfollicular papules with a central keratotic plug over the extensor aspect of upper and lower extremities for the last six months. The patient had diabetes and was on irregular medication. Dermoscopic examination revealed a three-zone concentric pattern with a central keratotic plug [Figure 1a], a white homogenous area (white-collar sign), and an outer zone of hyperpigmentation. Few lesions had a central yellow-to-brown hemorrhagic crust surrounded by red structureless areas [Figure 1b]. There were also hairpin vessels [Figure 1c] and focal red dots [Figure 1d] in the periphery. We made a final diagnosis of acquired perforating dermatosis. Acquired perforating dermatosis present as pruritic papules, with a central keratotic core, on the legs. The dermoscopic appearance of a three-zone concentric pattern, white-collar sign, focal red dots/globules, and peripheral hairpin vessels are helpful clues in the diagnosis of acquired perforating dermatosis.^[1]

Close

Figure 1:

(a) Three-zone concentric pattern with a central keratotic plug, white collar of homogenous area, and an outer zone of hyperpigmentation; (b) Central yellow-to-brown hemorrhagic crust surrounded by red structureless areas; (c) Peripheral hairpin vessels in the white homogenous area (white-collar sign) surrounding the central keratotic plug; (d) Focal red dots in the white homogenous area (white-collar sign) surrounding the central keratotic plug.

Export to PPT