Idiopathic pulmonary hemosiderosis (IPH) is an uncommon cause of diffuse alveolar hemorrhage (DAH). Patients with IPH usually present with hemoptysis, and the diagnosis is often delayed by years. Patients often present with intermittent episodes of hemoptysis interspersed between periods of relative normalcy. However, massive hemorrhage resulting in acute respiratory failure and non-remitting hemoptysis have also been described. The classic triad includes hemoptysis, radiologic lung infiltrate, and iron deficiency anemia. Several hypotheses regarding the pathogenesis of IPH have been proposed. These risk factors include an autoimmune, allergic or genetic predisposition, and possible environmental exposure. Since IPH appears to be responsive to corticosteroids, the autoimmune hypothesis is considered to play a crucial role. A diagnosis of IPH requires exclusion of other etiologies of DAH, including infection, medications, toxic inhalation, vasculitis, and anti-glomerular basement membrane disease, among others. Histologically, IPH is characterized by the presence of hemosiderin-laden macrophages in the alveolar space without any evidence of vasculitis or immunocomplex deposition. Corticosteroid therapy represents the primary modality of treatment. Other immunosuppressive medications have also been used with varying success, especially in the setting of steroid-refractory disease. The prognosis of IPH in adults is somewhat better compared to the pediatric population. The severity of the initial presentation does not predict future outcomes. Which risk factors and patient characteristics are associated with a poor outcome are also unknown. More research is necessary to elucidate the pathophysiology and appropriate treatment.

特发性肺含铁血黄素沉着症（IPH）是弥漫性肺泡出血（DAH）的罕见原因。 IPH 患者通常会出现咯血，并且诊断往往会延迟数年。患者经常出现间歇性咯血，散布在相对正常的时期之间。然而，也有报道称大出血导致急性呼吸衰竭和非缓解性咯血。典型的三联征包括咯血、放射学肺部浸润和缺铁性贫血。已经提出了关于 IPH 发病机制的几种假设。这些风险因素包括自身免疫、过敏或遗传倾向，以及可能的环境暴露。由于 IPH 似乎对皮质类固醇有反应，因此自身免疫假说被认为发挥着至关重要的作用。 IPH 的诊断需要排除 DAH 的其他病因，包括感染、药物、有毒物质吸入、血管炎和抗肾小球基底膜疾病等。在组织学上，IPH 的特征是肺泡腔中存在富含含铁血黄素的巨噬细胞，但没有任何血管炎或免疫复合物沉积的证据。皮质类固醇治疗是主要的治疗方式。其他免疫抑制药物的使用也取得了不同程度的成功，特别是在类固醇难治性疾病的情况下。与儿童相比，成人 IPH 的预后要好一些。最初表现的严重程度并不能预测未来的结果。哪些风险因素和患者特征与不良结果相关尚不清楚。需要更多的研究来阐明病理生理学和适当的治疗。