Department of Dermato-Allergology, National Allergy Research Centre and Allergy Clinic, Copenhagen University Hospital Gentofte, 2900 Hellerup, Denmark.
Contact Dermatitis. 2016 Jan;74(1):29-36. doi: 10.1111/cod.12487. Epub 2015 Nov 11.
Chlorhexidine is a widely used disinfectant in the healthcare setting and in cosmetic products. A high prevalence of chlorhexidine contact allergy was reported in Denmark in the 1980s (2.0-5.4% of patients patch tested). It is unknown whether the prevalence is still high, which products cause the contact allergy, and whether accidental re-exposure occurs in some patients.
To estimate the prevalence of chlorhexidine contact allergy in a tertiary dermatology clinic in Denmark; to investigate whether patch testing with both chlorhexidine diacetate and chlorhexidine digluconate is necessary; to investigate how many patients have combined immediate-type allergy and contact allergy; and to identify which products cause chlorhexidine contact allergy, and whether patients are accidentally re-exposed.
This was a retrospective study including all patients patch tested with chlorhexidine during 2003-2013 at the Department of Dermato-Allergology at Copenhagen University Hospital Gentofte (n = 8497). All patients with a positive patch test reaction to chlorhexidine were sent a questionnaire comprising questions about the cause of the allergy and re-exposure.
Overall, 1.0% (n = 82) of all patients patch tested with chlorhexidine were positive. A decrease in the prevalence was observed over time, most likely because of lowering of the test concentration from 1.0 to 0.5% in 2008. Of the 82 patients, 28 (0.3%) had positive test reactions to both chlorhexidine salts, 43 (0.5%) had a positive test reaction only to chlorhexidine diacetate, and 11 (0.1%) had a positive test reaction to chlorhexidine digluconate. Three patients were both patch test-positive and prick test-positive. A known cause of the allergy was reported by 19 patients (40%) in the questionnaire: the products used in the healthcare setting were mainly reported, but some reported cosmetic products. Accidental re-exposure was reported by 15 patients (32%), of whom 13 reported symptoms.
The prevalence of chlorhexidine contact allergy does not seem to be higher in Denmark than in other European countries. Patch testing with both chlorhexidine diacetate and chlorhexidine digluconate may be beneficial. Testing for immediate-type allergy in patients with a positive patch test reaction to chlorhexidine is recommended. Chlorhexidine-containing products used in the healthcare setting and in cosmetics are potential causes of sensitization and allergy. Re-exposure is common, highlighting the fact that patients and healthcare personnel need to be well informed about possible sources of exposure.
洗必泰在医疗环境和化妆品中被广泛用作消毒剂。20 世纪 80 年代，丹麦报道了高比例的洗必泰接触过敏（2.0-5.4%的患者斑贴试验阳性）。目前尚不清楚该比例是否仍然较高，哪些产品会引起接触过敏，以及某些患者是否会意外再次接触。
评估丹麦哥本哈根大学医院 Gentofte 皮肤科诊所中洗必泰接触过敏的流行率；调查是否需要同时进行洗必泰双醋酸盐和洗必泰葡萄糖酸盐斑贴试验；调查有多少患者同时患有即刻型过敏和接触过敏；以及确定引起洗必泰接触过敏的产品，以及患者是否意外再次接触。
这是一项回顾性研究，纳入了 2003 年至 2013 年间在哥本哈根 Gentofte 大学医院皮肤科接受洗必泰斑贴试验的所有患者（n=8497）。所有对洗必泰斑贴试验阳性的患者均会收到一份问卷，内容包括过敏原因和再暴露情况。
总体而言，接受洗必泰斑贴试验的所有患者中，有 1.0%（n=82）为阳性。随着时间的推移，观察到阳性率有所下降，这很可能是因为 2008 年将测试浓度从 1.0%降低至 0.5%。在 82 名患者中，28 名（0.3%）对两种洗必泰盐均有阳性反应，43 名（0.5%）仅对洗必泰双醋酸盐有阳性反应，11 名（0.1%）对洗必泰葡萄糖酸盐有阳性反应。3 名患者斑贴试验和点刺试验均为阳性。在问卷调查中，有 19 名患者（40%）报告了过敏的已知原因：主要报告了在医疗环境中使用的产品，但也有一些报告了化妆品。15 名患者（32%）报告了意外再次接触，其中 13 名患者有症状。
丹麦的洗必泰接触过敏流行率似乎并不高于其他欧洲国家。同时进行洗必泰双醋酸盐和洗必泰葡萄糖酸盐斑贴试验可能有益。建议对洗必泰斑贴试验阳性的患者进行即刻型过敏检测。在医疗环境和化妆品中使用的含洗必泰的产品是致敏和过敏的潜在原因。再次暴露很常见，这突显了患者和医务人员需要充分了解可能的暴露源。
