BACKGROUND Acne scarring can be divided into 2 types: atrophic and hypertrophic scars. Papular acne scars are commonly encountered, skin-colored papules on the chin and back. OBJECTIVE This study aimed to estimate the prevalence of each acne scar type and to investigate the clinical manifestations of papular acne scars. METHODS This retrospective study included 416 patients with acne scars. Dermatologists classified the scars into 3 types (atrophic, papular, and keloid type) based on clinical photographs and analyzed the clinical and histologic features of papular acne scars. RESULTS Among 416 patients with acne scars, 410 patients (98.56%) had atrophic scars, 53 patients (12.74%) had keloid scars, and 46 patients (11.06%) had papular acne scars. Twenty patients (4.81%) had both papular and keloid acne scars. Histologic analysis showed fibrotic tissue in both keloid and papular acne scars. Fibrosis of the papular scar was limited to the upper dermis. CONCLUSION Papular acne scars were significantly more prevalent in patients with keloid scars than in those without keloid scars. These results provide a basis for understanding papular acne scars, which have been under-recognized. The association between papular and keloid acne scars can suggest the decision for scar treatment.

中文翻译：

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被忽视的痤疮疤痕类型：丘疹性痤疮疤痕及其与瘢痕疙瘩的相关性。

背景技术痤疮疤痕可分为两种类型：萎缩性疤痕和肥厚性疤痕。丘疹性痤疮疤痕是常见的，下巴和背部出现肤色丘疹。目的本研究旨在估计每种痤疮疤痕类型的患病率并调查丘疹性痤疮疤痕的临床表现。方法 这项回顾性研究纳入了 416 名痤疮疤痕患者。皮肤科医生根据临床照片将疤痕分为3种类型（萎缩型、丘疹型和疤痕疙瘩型），并分析丘疹性痤疮疤痕的临床和组织学特征。结果 416例痤疮疤痕患者中，萎缩性疤痕410例（98.56%），瘢痕疙瘩53例（12.74%），丘疹状痤疮疤痕46例（11.06%）。20 名患者（4.81%）同时患有丘疹性痤疮疤痕和瘢痕疙瘩性痤疮疤痕。组织学分析显示瘢痕疙瘩和丘疹性痤疮疤痕中均存在纤维化组织。丘疹疤痕的纤维化仅限于真皮上层。结论 丘疹性痤疮疤痕在有疤痕疙瘩的患者中明显比无疤痕疙瘩的患者更常见。这些结果为了解丘疹性痤疮疤痕提供了基础，而丘疹性痤疮疤痕一直未被充分认识。丘疹性痤疮疤痕和瘢痕疙瘩性痤疮疤痕之间的关联可以提示疤痕治疗的决定。