Recurrent anaphylaxis to synthetic folic acid
Recurrent anaphylaxis to synthetic folic acid
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对合成叶酸反复过敏
DOI：
10.1016/s0140-6736(07)61330-0
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
C. Wall
中科院分区：
文献类型：
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作者：
Julie Smith;M. Empson;C. Wall
用合成叶酸（翼酰基单胺酸）进行食品强化，在益处、安全性和消费者选择方面仍然存在争议。一些国家已经采用了强制性叶酸强化。2007年6月，在澳大拉西亚做出了继续进行的决定。我们报告的情况下，一名妇女谁有三次发作的I型过敏症，包括抗过敏反应，合成叶酸暴露后。她的第一次发作发生在服用5毫克叶酸片的几分钟内。她出现喉咙发痒、恶心、全身皮疹、腹泻和头晕；她接受了抗历史地雷治疗。第二次发作是在饮用加20微克/100毫升叶酸的800毫升石灰味水之后。喝完饮料几分钟后，她喉咙发痒，全身瘙痒，恶心。她接受了肾上腺素和抗组胺药治疗。再一次发作发生在饮用150毫升含飞果果（桃金娘科的一种水果）和含53.5 μg/100 mL叶酸的补品的饮料几分钟内。她出现全身性皮疹、呕吐和头晕。在去医院的路上注射了肾上腺素，效果很好。叶酸皮内试验0.05 μg/mL含叶酸、碳酸氢盐和水的溶液呈阳性（9 mm旋轮，35 mm旋轮）。对照患者为阴性。其他食品和饮料产品的皮肤点刺试验呈阴性。对叶酸溶液进行分级、盲法刺激，剂量为160 μg时导致广泛传播的荨麻疹。在她第一次发作之前，她服用了复合维生素B补充剂，并回忆起反复发作的荨麻疹，可能是在这个时候对叶酸过敏。她似乎对饮食中的叶酸（翼酰基聚谷氨酸）耐受。对合成叶酸过敏的报道很少。2-4一份报告记录了对药物合成叶酸（作为食品补充剂）的敏感性，也可能对膳食叶酸敏感。在另一个叶酸暴露于多种维生素制剂后发生过敏反应的病例中，体内和体外测试显示对叶酸的IgE抗体的发展。在ige介导的反应中，分子量仅为441 D的叶酸可能通过与自身蛋白结合而充当半抗原。叶酸强化必须附有清晰的食品标签，以使过敏的人避免危及生命的反应。在特发性过敏反应和疑似谷物过敏的鉴别诊断中，当皮肤刺痛或对标准谷物的RAST试验尚无定论时，应考虑叶酸过敏。
Food fortification with synthetic folic acid (pteroyl monoglutamic acid) remains a source of debate in terms of benefit versus issues of safety and consumer choice. 1 Several countries have adopted mandatory folic acid fortification. A decision to proceed in Australasia was made in June, 2007. We report the case of a woman who had three episodes of type I hypersensitivity, including ana phylaxis, after synthetic folic acid exposure. Her first episode occurred within minutes of taking a 5 mg folic acid tablet. She devel oped an itchy throat, nausea, gener alised rash, diarrhoea, and lightheaded ness; she was treated with anti hista mines. The second episode followed consumption of 800 mL lime-flavoured water fortified with 20 μg/100 mL folic acid. Within minutes of finishing the drink she developed an itchy throat, generalised pruritus, and nausea. She was treated with adrena line and antihistamines. A further episode occurred within minutes of drinking 150 mL of a beverage containing feijoa (a fruit of the Myrtaceae family) and supple ments including 53· 5 μg/100 mL folic acid. She developed gener alised rash, vomiting, and lightheaded ness. Adrenaline was given en route to hospital, with good response. Intradermal testing with folic acid 0· 05 μg/mL solution containing folic acid, bicarbonate, and water was positive (9 mm wheal, 35 mm flare). A control patient was negative. Skin-prick tests to other food and beverage products were negative. A graded, blinded chal lenge to the folic acid solu tion led to wide spread urticaria at a dose of 160 μg. Before her first episode she had taken a multivitamin B supplement and recalled recurrent episodes of urticaria, and presumably sensitisation to folic acid occurred at this time. She seems to tolerate dietary folates (pteroylpolyglutamates). Hypersensitivity to synthetic folic acid has been rarely described. 2-4 One report documents sensitivity to synthetic folic acid in medication, as a food supplement, and possibly to dietary folate. 2 In a further case of anaphylaxis after folic acid exposure in multivitamin preparations, development of IgE antibody to folic acid was shown by in-vivo and in-vitro testing. 3 In IgE-mediated reactions, folic acid, with a molecular weight of only 441 D, probably acts as a hapten by conjugation with self-proteins. 3 Folic acid fortification must be accompanied by clear food labelling to enable those who develop allergy to avoid life-threatening reactions. Folic acid allergy should be considered in the differential diagnosis of idiopathic anaphylaxis and suspected cereal allergy where skin-prick or RAST testing to standard grains is inconclusive.