Prurigo chronica multiformis is a commonly used diagnostic designation for a peculiar subtype of prurigo in Japan, although the disease entity might not be well-recognized in other countries. Experts approved by the Japanese Dermatological Association attempted to build a common consensus on prurigo chronica multiformis, agreeing that it is a unique and important disease entity in elderly patients. Skin lesions are characterized by intensely pruritic, edematous, urticarial papules, or small macules, which gradually become solid papules/small nodules. The papules tend to aggregate and occasionally coalesce into polygonal lichenified plaques. The most commonly affected sites are the lower abdomen and lower back, although the chest, thighs, and upper back might also be involved. Common histopathological features of prurigo chronica multiformis include infiltration of lymphocytes and eosinophils in the upper dermis, with minimal epidermal changes. Basophil infiltration is also observed. The epidemiological incidence, differences in clinical manifestations by geographical location, and disease placement among other forms of prurigo and/or related skin diseases need to be further elucidated. Dermatologists should be aware of the clinical characteristics of prurigo chronica multiformis.

慢性多形性痒疹是日本一种特殊亚型痒疹的常用诊断名称，尽管这种疾病实体在其他国家可能不被很好地认识。经日本皮肤病协会批准的专家试图就慢性多形性痒疹建立共识，一致认为这是老年患者中一种独特而重要的疾病实体。皮肤病变的特征是强烈瘙痒、水肿、荨麻疹丘疹或小斑疹，这些斑疹逐渐变成实性丘疹/小结节。丘疹倾向于聚集，偶尔合并成多边形苔藓样斑块。最常见的受累部位是下腹部和下背部，尽管胸部、大腿和上背部也可能受累。慢性多形性痒疹的常见组织病理学特征包括真皮上部淋巴细胞和嗜酸性粒细胞浸润，表皮变化很小。也观察到嗜碱性粒细胞浸润。其他形式的痒疹和/或相关皮肤病的流行病学发病率、临床表现的地理位置差异和疾病分布需要进一步阐明。皮肤科医生应了解慢性多形性痒疹的临床特点。