Department of Occupational and Environmental Dermatology, Lund University, Skane University Hospital, Malmö, Sweden.
Br J Dermatol. 2011 Mar;164(3):568-72. doi: 10.1111/j.1365-2133.2010.10151.x. Epub 2011 Feb 3.
It has been found that patch testing with 15 μL formaldehyde 2·0% aq. detects twice as many allergies as by testing with 1·0%. The clinical relevance of positive patch test reactions is often difficult to determine. Repeated open application tests are simple to do and help to evaluate the significance of patch test results.
To study the clinical relevance of contact allergy to formaldehyde detected by 2·0% formaldehyde (0·60 mg cm(-2) ) but not by 1·0%.
Eighteen patients positive to formaldehyde 2·0% but negative to 1·0%, and a control group of 19 patients with dermatitis but without allergy to parabens, formaldehyde and formaldehyde releasers were included in the study. Formaldehyde 2000 p.p.m., the maximum concentration permitted in leave-on cosmetics according to the EU Cosmetics Directive, was added to a batch of moisturizer preserved with parabens. The same batch without formaldehyde served as a control. The study was double-blinded and randomized. The patients were provided with both moisturizers and instructed to apply one of them twice a day on a marked-out 5 × 5-cm area on the inside of one upper arm and the other moisturizer on the other arm. Reading of the test sites was done once a week for a maximum of 4 weeks.
In the control group there were no allergic reactions to either of the moisturizers. Nine of 17 formaldehyde-allergic patients reacted with an allergic reaction to the moisturizer which contained formaldehyde (P < 0·001). No positive reactions were observed to the moisturizer without formaldehyde.
Our results demonstrate that contact allergy to formaldehyde 2·0% may be clinically relevant.
已经发现，使用 15μL 2.0%甲醛水溶液进行斑贴试验比使用 1.0%甲醛检测出的过敏反应多一倍。阳性斑贴试验反应的临床相关性往往难以确定。重复开放性应用试验操作简单，有助于评估斑贴试验结果的意义。
研究用 2.0%甲醛（0.60mg/cm²）而非 1.0%甲醛检测到的接触性过敏对甲醛的临床相关性。
纳入 18 例对 2.0%甲醛阳性但对 1.0%甲醛阴性的患者，以及 19 例患有皮炎但对防腐剂、甲醛和甲醛释放剂无过敏的对照组患者。将 2000ppm 的甲醛（欧盟化妆品指令允许的驻留类化妆品中的最大浓度）添加到一批用防腐剂保存的保湿剂中。不含甲醛的同一批保湿剂作为对照。该研究为双盲和随机的。向患者提供两种保湿剂，并指导他们每天在一只上臂的 5×5cm 标记区域内涂抹一种保湿剂，另一只手臂涂抹另一种保湿剂。每周最多读取 4 周的测试部位。
在对照组中，两种保湿剂均未引起过敏反应。17 例甲醛过敏患者中有 9 例对含有甲醛的保湿剂出现过敏反应（P<0.001）。对不含甲醛的保湿剂未观察到阳性反应。
我们的结果表明，2.0%甲醛的接触性过敏可能具有临床相关性。
