Allergy Unit, Internal Medicine, Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy.
Allergy and Clinical Immunology Residency Program, Marche Polytechnic University, Ancona, Italy.
Clin Exp Allergy. 2019 Jul;49(7):942-952. doi: 10.1111/cea.13402. Epub 2019 May 13.
Idiopathic anaphylaxis (IA) or spontaneous anaphylaxis is a diagnosis of exclusion when no cause can be identified. The exact incidence and prevalence of IA are not known. The clinical manifestations of IA are similar to other known causes of anaphylaxis. A typical attack is usually acute in onset and can worsen over minutes to a few hours. The pathophysiology of IA has not yet been fully elucidated, although an IgE-mediated pathway by hitherto unidentified trigger/s might be the main underlying mechanism. Elevated concentrations of urinary histamine and its metabolite, methylimidazole acetic acid, plasma histamine and serum tryptase have been reported, consistent with mast cell activation. There is some evidence that corticosteroids reduce the frequency and severity of episodes of IA, consistent with a steroid-responsive condition. Important differential diagnoses of IA include galactose alpha-1,3 galactose (a carbohydrate contained in red meat) allergy, pigeon tick bite (Argax reflexus), wheat-dependent exercise-induced anaphylaxis, Anisakis simplex allergy and mast cell disorders. Other differential diagnoses include "allergy-mimics" such as asthma masquerading as anaphylaxis, undifferentiated somatoform disorder, panic attacks, globus hystericus, vocal cord dysfunction, scombroid poisoning, vasoactive amine intolerance, carcinoid syndrome and phaeochromocytoma. Acute treatment of IA is the same as for other forms of anaphylaxis. Long-term management is individualized and dictated by frequency and severity of symptoms and involves treatment with H1 and H2 receptor blockers, leukotriene receptor antagonist and consideration for prolonged reducing courses of oral corticosteroids. Patients should possess an epinephrine autoinjector with an anaphylaxis self-management plan. There are anecdotal reports regarding the use of omalizumab. For reasons that remain unclear, the prognosis of IA is generally favourable with appropriate treatment and patient education. If remission cannot be achieved, the diagnosis should be reconsidered.
特发性过敏反应（IA）或自发性过敏反应是一种排除性诊断，当无法确定病因时采用。IA 的确切发病率和患病率尚不清楚。IA 的临床表现与其他已知的过敏反应原因相似。典型的发作通常是急性发作，可以在数分钟到数小时内恶化。IA 的病理生理学尚未完全阐明，尽管 hitherto 未识别的触发因素可能通过 IgE 介导途径是主要的潜在机制。已报道尿组胺及其代谢物甲基咪唑乙酸、血浆组胺和血清胰蛋白酶原升高，与肥大细胞激活一致。有一些证据表明皮质类固醇可降低 IA 发作的频率和严重程度，与类固醇反应性疾病一致。IA 的重要鉴别诊断包括半乳糖α-1,3 半乳糖（红肉类中含有的碳水化合物）过敏、鸽蜱咬伤（Argax reflexus）、小麦依赖运动诱导的过敏反应、Anisakis simplex 过敏和肥大细胞疾病。其他鉴别诊断包括“过敏模拟物”，如伪装成过敏反应的哮喘、未分化躯体形式障碍、惊恐发作、假性球麻痹、声带功能障碍、鲭鱼中毒、血管活性胺不耐受、类癌综合征和嗜铬细胞瘤。IA 的急性治疗与其他形式的过敏反应相同。长期管理是个体化的，取决于症状的频率和严重程度，包括 H1 和 H2 受体阻滞剂、白三烯受体拮抗剂的治疗，并考虑长期口服皮质类固醇的降低疗程。患者应随身携带肾上腺素自动注射器和过敏反应自我管理计划。有关于奥马珠单抗使用的一些传闻报告。由于原因尚不清楚，IA 的预后一般良好，适当的治疗和患者教育。如果无法缓解，应重新考虑诊断。
