Harvard Medical School, Boston, MA 02115, USA.
Department of Dermatology, Massachusetts General Hospital, Boston, MA 02114, USA.
Contact Dermatitis. 2018 Mar;78(3):208-210. doi: 10.1111/cod.12928. Epub 2017 Nov 27.
The use of metal-containing bio-devices is becoming increasingly common. Self-reported history of dermatitis with metal exposure is not established as being predictive for metal allergy.
To assess the validity of two screening questions addressing metal allergy.
At Massachusetts General Hospital Contact Dermatitis Clinic, 2132 consecutive patients were asked either 'Do you get rashes when jewellery touches your skin' (Q1; N = 1816) or 'Do you get rashes when metal touches your skin?' (Q2; N = 316) before being patch tested.
Testing showed that 20% of subjects had positive reactions to nickel, 7.4% had positive reactions to cobalt, and 5.8% had positive reactions to chromium. Q1 was 40% sensitive (95%CI: 35-45%). The positive predictive value (PPV) was 51%, and the negative predictive value (NPV) was 82%. Q2 was 77% sensitive (95%CI: 68-84%). The PPV was 71%, and the NPV was 84%. Q2 was 37% more sensitive than Q1 (p < 0.0001), with a higher relative risk (RR) (4.75, p < 0.001) than Q1 (RR = 3.01, p < 0.001).
Patient-reported metal allergy, although not perfect, is a reasonable method for metal allergy screening to help identify those needing further objective evaluation by patch testing.
含金属的生物设备的使用越来越普遍。有金属暴露性皮炎史的自我报告并不能预测金属过敏。
评估两个用于筛查金属过敏的问题的有效性。
在马萨诸塞州总医院接触性皮炎诊所，在进行斑贴试验之前，连续询问了 2132 名患者，其中 1816 名患者被问到“珠宝接触皮肤时您是否会出现皮疹”（问题 1；N=1816），316 名患者被问到“金属接触皮肤时您是否会出现皮疹”（问题 2；N=316）。
检测显示，20%的受试者对镍呈阳性反应，7.4%对钴呈阳性反应，5.8%对铬呈阳性反应。问题 1 的敏感性为 40%（95%CI：35-45%）。阳性预测值（PPV）为 51%，阴性预测值（NPV）为 82%。问题 2 的敏感性为 77%（95%CI：68-84%）。PPV 为 71%，NPV 为 84%。问题 2 比问题 1 敏感 37%（p<0.0001），相对风险（RR）更高（4.75，p<0.001），而问题 1 的 RR 为 3.01（p<0.001）。
尽管不完美，但患者自述的金属过敏是一种合理的金属过敏筛查方法，可以帮助识别那些需要进一步进行斑贴试验客观评估的患者。
