University of California San Francisco, San Francisco, CA, USA.
Clin Rev Allergy Immunol. 2022 Jun;62(3):548-561. doi: 10.1007/s12016-022-08924-2. Epub 2022 Feb 3.
Confirming drug imputability is an important step in the management of cutaneous adverse drug reactions (CADR). Re-challenge is inconvenient and in many cases life threatening. We review the literature on ideal patch testing technique for specific CADRs. Testing should be performed approximately 3 months after the resolution of the eruption using standard patch testing techniques. Commercially available patch test preparations are available for a minority of drugs, so in most cases, testing should be performed with the drug at various recommended concentrations and in different vehicles. Testing to all known excipients, such as dyes, vehicles and preservatives is also important. Immunosuppressive medications should be discontinued or down titrated to the lowest tolerable dose to decrease the risk of false negative reactions. We provide an overview of expert recommendations and extant evidence on the utility of patch testing for identifying the culprit drug in common CADRs and for specific drug or drug classes. Overall, there appears to be significant variability in the patch test positivity of different drugs, which is likely the result of factors intrinsic to the drug such as dermal absorption (as a function of lipophilicity and molecular size) and whether the drug itself or a downstream metabolite is implicated in the immune reaction. Drugs with high patch test positivity rates include beta-lactam antibiotics, aromatic anticonvulsants, phenytoin, and corticosteroids, among others. Patch testing positivity varies both as a function of the drug and type of CADR. The sum of the evidence suggests that patch testing in the setting of morbilliform eruptions, fixed drug eruption, acute generalized exanthematous pustulosis, and possibly also drug-induced hypersensitivity syndrome, photoallergic and eczematous reactions may be worthwhile, although utility of testing may vary on the specific drug in question for the eruption. It appears to be of limited utility and is not recommended in the setting of other complex CADR, such as SJS/TEN and leukocytoclastic vasculitis.
确认药物的因果关系是处理皮肤不良反应 (CADR) 的重要步骤。重新用药试验既不方便，在许多情况下又危及生命。我们复习了有关特定 CADR 的理想斑贴试验技术的文献。在皮疹消退后大约 3 个月，应使用标准斑贴试验技术进行测试。目前仅有少数药物有市售的斑贴试验制剂，因此在大多数情况下，应使用各种推荐浓度的药物，并在不同载体中进行测试。测试所有已知的赋形剂，如染料、载体和防腐剂也很重要。为降低假阴性反应的风险，应停用或减少免疫抑制药物的剂量至最低耐受剂量。我们概述了专家对斑贴试验在确定常见 CADR 中的致病药物以及特定药物或药物类别的用途的建议和现有证据。总体而言，不同药物的斑贴试验阳性率差异很大，这可能是药物内在因素的结果，如皮肤吸收（与脂溶性和分子大小有关），以及是药物本身还是下游代谢物引起免疫反应。斑贴试验阳性率高的药物包括β-内酰胺类抗生素、芳香性抗惊厥药、苯妥英和皮质类固醇等。斑贴试验阳性率既取决于药物，也取决于 CADR 的类型。综合证据表明，在麻疹样发疹、固定性药物疹、急性泛发性脓疱性银屑病，以及可能还有药物超敏反应综合征、光过敏性和湿疹性反应的情况下，斑贴试验可能是值得的，尽管针对具体的药物，测试的实用性可能有所不同。在其他复杂的 CADR（如 SJS/TEN 和白细胞碎裂性血管炎）中，其作用有限，不建议使用。
