A new occlusive patch test system comparable to IQ and Finn chambers.

Background: A good patch test system should have good adhesion and contact, and minimal leakage; Finn and IQ patch test system have these properties but are expensive. Aims: To develop a new cost‑effective occlusive patch test system that had good contact with the skin and was non‑irritant. Methods: The system (designated Chamber X) was fabricated using a semi‑permeable tape and a flexible virgin plastic chamber. Chamber X was developed by (i) selecting adhesive tape based on its non irritancy and adhesive potential (ii) testing plastic chamber material for its skin irritancy (iii) testing the assembled system against Finn, IQ and locally available chambers for irritancy, contact, leakage and occlusivity. Results: Chamber X showed better occlusion than IQ, Finn and locally available chambers and was comparable to, (P > 0.05) IQ and Finn in terms of irritancy, contact and leakage. Conclusions: The results demonstrate that the Chamber X offers a cost effective patch test system comparable to IQ and Finn chambers in terms of safety, adhesion, leakage and occlusivity.

Evaluating the Nickel Content in Metal Alloys and the Threshold for Nickel-Induced Allergic Contact Dermatitis

Many patients are currently suffering from nickel (Ni)-induced allergic contact dermatitis (ACD). There have been few Korean studies dealing with the threshold of Ni-induced ACD and quantifying the total amount of Ni in the metal alloys. The aim of this study is to evaluate the amount of Ni leached from metal alloys and Ni contents in metal alloys, and to estimate the threshold of Ni-induced ACD. All the earrings we examined leached below 0.5 microgram/cm(2)/week, the upper limit of European Union (EU) regulation, but the other metal alloys leached a much higher amount of Ni than the limit. Likewise, all the earrings we examined contained less than 0.05% Ni (500 microgram/g), the upper limit of EU regulation, but the other metal alloys exceeded this limit. Twenty Ni-sensitive subjects, who were patch-tested with various concentrations of Ni sulphate, showed positive reactions to 5% and 1% Ni sulphate, 10 subjects showed positive reactions to 0.01%, and the most sensitive subject showed reaction even to 0.0001%. The subjects in this study were more sensitive to Ni than those in the previous studies done in Europe. Taken together, strictly regulating the Ni-containing alloys that are made in Korea is needed to lower the occurrence of Ni-induced ACD.