Centro Hospitalar e Universitário de Coimbra, Departamento de Pediatria, Serviço de Pediatria Ambulatória, Unidade de Nefrologia Pediátrica, Coimbra, Portugal.
J Bras Nefrol. 2021 Oct-Dec;43(4):603-607. doi: 10.1590/2175-8239-JBN-2020-0101.
Psoriasis is a chronic immune-mediated disorder that primarily affects the skin in both adults and children but can also have systemic involvement, particularly with arthritis and kidney injury. IgA nephropathy is the most frequent kidney disorder associated with psoriasis. Approximately one third of all cases of psoriasis begin in childhood, but association between psoriasis and renal disorders has scarcely been reported in pediatric patients. Henoch-Schönlein purpura (HSP) is a systemic vasculitis characterized by IgA deposits in the vessel walls of affected organs and in the mesangium of the kidney. HSP nephritis histopathology is identical to IgA nephropathy.
A 6-year-old boy with recent onset of psoriasis developed HSP with kidney involvement, clinically manifested by nephrotic-range proteinuria and hematuria. Kidney biopsy revealed fibrocellular glomerular crescents and mesangial IgA deposits compatible with IgA nephropathy. Treatment with systemic corticosteroids led to the control of hematuria, but as nephrotic-range proteinuria persisted, cyclophosphamide was added, leading to a gradual decrease in proteinuria.
We propose an underlying common mechanism in the pathogenesis of both HSP and psoriasis, involving a dysregulation of the IgA-mediated immune response, which could predispose to both entities as well as to kidney damage and IgA nephropathy in these patients.
银屑病是一种慢性免疫介导的疾病，主要影响成人和儿童的皮肤，但也可能有全身受累，特别是关节炎和肾脏损伤。IgA 肾病是与银屑病最相关的肾脏疾病。大约三分之一的银屑病病例始于儿童期，但在儿科患者中，银屑病与肾脏疾病之间的关联鲜有报道。过敏性紫癜（HSP）是一种全身性小血管炎，其特征是受影响器官的血管壁和肾脏系膜中 IgA 沉积。HSP 肾炎的组织病理学与 IgA 肾病相同。
一名 6 岁男孩近期出现银屑病，并发 HSP 伴肾脏受累，临床表现为肾病范围蛋白尿和血尿。肾脏活检显示纤维细胞性肾小球新月体和系膜 IgA 沉积，符合 IgA 肾病。全身皮质类固醇治疗后血尿得到控制，但由于肾病范围蛋白尿持续存在，加用环磷酰胺，导致蛋白尿逐渐减少。
我们提出 HSP 和银屑病发病机制中存在共同的潜在机制，涉及 IgA 介导的免疫反应失调，这可能使这些患者易患两种疾病以及肾脏损伤和 IgA 肾病。
