Department of Dermatology, University Medical Centre Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands.
Department of Clinical Social Medicine, Occupational and Environmental Dermatology, University Hospital Heidelberg, 69115, Heidelberg, Germany.
Contact Dermatitis. 2018 Feb;78(2):143-150. doi: 10.1111/cod.12912. Epub 2017 Nov 27.
Studies have shown that not all positive patch test reactions are reproducible upon retesting, that is, persistent. Non-persistent reactions might represent initial false-positive reactions, meaning that patients might unnecessarily avoid allergens.
To investigate the occurrence of both persistent and non-persistent patch test reactions, to explore possible explanations, and to investigate whether allergen-specific differences exist.
A retrospective analysis was performed on patients who were patch tested at least twice between 1 January 1995 and 31 October 2016, with at least one positive patch test reaction to an allergen that had been retested. Both univariable and multivariable analyses were performed to investigate the influence of several factors on persistence.
Of 274 retested positive reactions in 119 patients, 183 (66.8%) reactions remained positive. The strongest predictor for non-persistence in both univariable and multivariable analyses was strength of the first patch test, with weak positive reactions being significantly less persistent. Regarding allergen groups, metals and fragrances were less persistent than other allergens.
Weak positive reactions have a low persistence rate, and the dermatologist should be conservative in advising the patient on avoidance of these allergens, especially if clinical relevance is uncertain.
研究表明，并非所有阳性斑贴试验反应在重新检测时都是可重现的，即持续存在的。非持续反应可能代表最初的假阳性反应，这意味着患者可能不必要地避免了过敏原。
调查持续性和非持续性斑贴试验反应的发生情况，探讨可能的解释，并研究是否存在过敏原特异性差异。
对 1995 年 1 月 1 日至 2016 年 10 月 31 日期间至少两次斑贴试验且至少有一个阳性斑贴试验反应被重新检测的患者进行回顾性分析。进行单变量和多变量分析，以研究多种因素对持续性的影响。
在 119 名患者的 274 个重复阳性反应中，183 个（66.8%）反应仍为阳性。在单变量和多变量分析中，非持续性的最强预测因素是首次斑贴试验的强度，弱阳性反应的持续性明显较低。就过敏原组而言，金属和香料比其他过敏原的持续性低。
弱阳性反应的持续性低，皮肤科医生在建议患者避免这些过敏原时应持保守态度，尤其是如果临床相关性不确定的话。
