OBJECTIVES Idiopathic mast cell disorders, a recently defined and recognised syndrome in clinical practice, are similar to the previously termed non-clonal mast cell disorder. Patients with idiopathic mast cell activation syndrome (MCAS) suffer all the classical signs of mast cell activation but do not have evidence of mast cell clonality. Furthermore, treatment of these patients can be limited and burdensome in those with refractory symptoms. METHODS Here, we describe treatment of a patient with idiopathic MCAS utilising a single monthly subcutaneous injection of omalizumab and review the current classification and therapeutic options for clonal and non-clonal MCAS. RESULTS Low-dose omalizumab treatment has successfully led to a 5-year, sustained clinical response, controlled debilitating symptoms of mast cell activation and allowed for reintroduction and long-term maintenance of bee venom subcutaneous immunotherapy. CONCLUSION Low-dose omalizumab of 150 mg monthly should be considered for maintenance management of patients with idiopathic MCAS for its cost and quality-of-life benefits.

中文翻译：

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低剂量奥马珠单抗成功治疗特发性肥大细胞活化综合征。

目标 特发性肥大细胞疾病是一种最近在临床实践中定义和认可的综合征，与之前称为非克隆性肥大细胞疾病的症状相似。患有特发性肥大细胞活化综合征 (MCAS) 的患者会出现肥大细胞活化的所有典型症状，但没有肥大细胞克隆性的证据。此外，对这些患者的治疗可能是有限的并且对于那些有难治性症状的患者来说是繁重的。方法 在这里，我们描述了使用单月皮下注射奥马珠单抗对特发性 MCAS 患者的治疗，并回顾了克隆和非克隆 MCAS 的当前分类和治疗选择。结果 低剂量奥马珠单抗治疗成功地产生了 5 年的持续临床反应，控制肥大细胞活化的衰弱症状，并允许重新引入和长期维持蜂毒皮下免疫疗法。结论 应考虑每月 150 mg 低剂量奥马珠单抗用于特发性 MCAS 患者的维持管理，因为其成本和生活质量益处。