Garbanzos Clint Christian T, Rios-Duarte Jorge A, Hardway Heather D, Todd Austin, Davis Dawn M R, Lehman Julia S
Department of Pathology and Laboratory Medicine, MedStar Georgetown University Hospital, Washington, District of Columbia, USA.
Department of Dermatology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA.
Pediatr Dermatol. 2025 Jul-Aug;42(4):767-772. doi: 10.1111/pde.15978. Epub 2025 May 29.
BACKGROUND/OBJECTIVES: Immune-mediated skin disorders, such as immunobullous dermatoses and leukocytoclastic vasculitis, rarely affect children. While direct immunofluorescence (DIF) biopsy is a standard diagnostic tool, limited data exist on pediatric DIF patterns, rates of positivity, pretest diagnostic concordance, and the relevance of biopsy site. This study sought to address these gaps.
DIF data from all skin and mucosal specimens interpreted at Mayo Clinic's reference immunodermatology laboratory for patients aged 0-18 years (August 22, 2017 to November 30, 2023) were reviewed. DIF results were classified as positive if a characteristic pattern was seen and negative if the findings were negative or nondiagnostic.
Of 986 pediatric DIF studies, 153 (15.5%) were positive and comparable to adult positivity rates (20.9%) during the same period. The most frequent DIF patterns were IgA-predominant vasculitis (N = 85/153; 55.5%) and lichenoid tissue reaction (N = 21/153;13.7%). Concordance between pretest diagnosis and positive DIF results was highest for linear IgA bullous dermatosis (N = 7/7; 100%) and dermatitis herpetiformis (N = 6/6; 100%). Excluding these entities, DIF changed the pretest diagnosis in 16.7% (N = 19/114) of cases. While lower extremity biopsies were initially more likely to yield positive DIF results, this association disappeared when IgA vasculitis cases were excluded.
The most frequent DIF pattern in children was that of IgA-predominant vasculitis. Pediatric DIF positivity rates closely mirrored those of adults, supporting similar biopsy thresholds. DIF results differed from the pretest impression in a substantial percentage, supporting the value of DIF in select situations in the pediatric population. After controlling for IgA vasculitis, biopsy site was not associated with DIF positivity.
背景/目的：免疫介导的皮肤疾病，如免疫性大疱性皮肤病和白细胞破碎性血管炎，很少影响儿童。虽然直接免疫荧光（DIF）活检是一种标准的诊断工具，但关于儿科DIF模式、阳性率、预测试诊断一致性以及活检部位的相关性的数据有限。本研究旨在填补这些空白。
回顾了梅奥诊所参考免疫皮肤病学实验室对0至18岁患者（2017年8月22日至2023年11月30日）所有皮肤和黏膜标本的DIF数据。如果观察到特征性模式，则DIF结果分类为阳性；如果结果为阴性或无法诊断，则分类为阴性。
在986项儿科DIF研究中，153项（15.5%）为阳性，与同期成人阳性率（20.9%）相当。最常见的DIF模式是IgA为主的血管炎（N = 85/153；55.5%）和苔藓样组织反应（N = 21/153；13.7%）。线性IgA大疱性皮肤病（N = 7/7；100%）和疱疹样皮炎（N = 6/6；100%）的预测试诊断与阳性DIF结果之间的一致性最高。排除这些疾病后，DIF在16.7%（N = 19/114）的病例中改变了预测试诊断。虽然下肢活检最初更有可能产生阳性DIF结果，但排除IgA血管炎病例后，这种关联消失了。
儿童中最常见的DIF模式是IgA为主的血管炎。儿科DIF阳性率与成人密切相似，支持相似的活检阈值。DIF结果在很大比例上与预测试印象不同，支持DIF在儿科人群某些情况下的价值。在控制IgA血管炎后，活检部位与DIF阳性无关。
