慢性特發性蕁麻疹

「慢性特發性蕁麻疹」乃指病程超過六週以上、無外來誘發因素、反覆發作的蕁麻疹。過去這些患者中，有八九成因找不到外來刺激因子而被視爲具有「特發性」。目前的證據顯示其中三至五成患者是因爲體內有對抗免疫球蛋白E受器或免疫球蛋白E本身的自體抗體。隨著我們對這些可活化肥大細胞或嗜鹼性球的自體抗體有更多的了解，「自體免疫性蕁麻疹」一詞便被用來描述並診斷這群病人。自體血清皮膚試驗是臨床上檢到這些自體抗體的重要篩檢試驗，有約八成的敏感性及特異性。慢性蕁麻疹患者的甲狀腺自體免疫性盛行率較一般群眾爲高，但抗甲狀腺抗體卻非慢性蕁麻疹的致病因子，而是與抗免疫球蛋白E受器自體抗體平行並存的自體免疫現象。感染於慢性蕁麻疹致病的角色則仍有待釐清。慢性蕁麻疹急者幽門螺旋稈菌盛行率與一般群眾相當，唯蕁麻疹患者可能對幽門螺旋稈菌之免疫反應與一般人不同而發展出自體免疫體質。有不少研究指出根除幽門螺旋稈菌可治癒或改善蕁麻疹。抗組織臉是治療這類蕁麻疹的第一線藥物，而鑑定病人是否爲自體免疫性蕁麻疹在臨床上有其重要性，因爲對抗組織胺療效不佳的自體免疫蕁麻疹患者可考慮使用免疫調節劑甚至免疫抑制劑來進一步治療此一惱人的慢性疾病。

關鍵字

慢性特發性蕁麻疹；自體免疫性蕁麻疹；抗高親合性免疫球蛋Ε E受器抗體；甲狀腺自體免疫性；幽門螺旋桿菌

並列摘要

Chronic idiopathic urticaria is recurrent itchy wheals with daily or almost daily occurrence for at least 6 weeks, without obvious cause. Eighty to 90% of these patients have no specific external cause for their disease, which is therefore labeled ”idiopathic” before. It is now recognized that as many as 30-50% of patients show evidence of autoantibodies directed against either the high-affinity IgE receptor or, less frequently, against IgE. The term autoimmune urticaria is used increasingly nowadays to reflect advances in knowledge about these functional autoantibodies that activate mast cells and basophils. Autologous serum skin test is a useful in vivo screening test for autoimmune urticaria, with both sensitivity and specificity about 80%. It is generally accepted that thyroid autoimmunity is more prevalent in patients with chronic urticaria. However, antithyroid antibodies are not a direct causative agent in chronic urticaria. It appears more likely that antithyroid antibodies and anti-IgE receptor antibodies are associated, but just parallel, autoimmune events. The role of infections in chronic urticaria remains intriguing but unresolved. The prevalence of Helicobacter pylori infection in chronic urticaria is similar to that found in the general population. However, patients with chronic urticaria may differ in their immune response to infections or may develop infection-induced autoreactivity/ autoimmunity. Remission or improvement of chronic urticaria after H. pylori eradication was shown is some studies. Non-sedating histamine receptor antagonists should be used as first-line agents in the treatment of these patients; however, identification of patients with autoimmune urticaria is of increasing importance because of immunotherapy. Cyclosporin, intravenous immunoglobulin or plasmapheresis has been reported to be successful in severely affected refractory patients.

並列關鍵字

Chronic idiopathic urticaria ； Autoimmune urticaria ； Anti-Fc ε RI ； Thyroid autoimmunity ； Helicobacter pylori

國際替代計量

慢性特發性蕁麻疹

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