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 µg/cm2/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 µg/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

Persistence of contact allergy:A retrospective analysis

Background. 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. Objectives. 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. Methods. 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. Results. 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. Conclusion. 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

Clinical and experimental studies in nickel allergy

Kliniska och experimentella studier av nickelallergi Nickelallergi är vanligt, särskilt hos kvinnor. Nickelallergi leder ofta till periodiskt eller kroniskt eksem, främst på händerna. Dessa eksem kan vara svårläkta och leda till långa sjukskrivningsperioder. Nickel finns överallt i omgivningen och det går inte att helt undvika exposition för denna metall. Clinical and experimental studies in nickel allergy Contact allergy to nickel is very common among females and frequently leads to recurrent or chronic hand eczema, which often is hard to treat and leads to long sick-leave periods. Nickel is ubiquitous and total avoidance of exposure to the allergen is impossible. The aim of the present study was to get better understanding of various factors of possible significance for allergic contact dermatitis from nickel. A large inter- and intraindividual variation in nickel patch test reactivity was found in nickel-hypersensitive persons. Thus, no one had the same reactivity at repeated testing, and also completely negative tests were seen. A previous dermatitis was shown to be important for the elicitation of allergic contact dermatitis from nickel on topical nickel exposure. A previous nickel dermatitis gave an increased reactivity while a previous, irritant (SLS) contact dermatitis gave a decreased reactivity. The time interval from the previous allergic or irritant contact dermatitis was important for reactivity. Flare-up reactions after oral challenge with nickel were found to be correlated to nickel dose, intensity of a previous eczema, and time after the eczema. Orally administered nickel results in increased nickel in urine and less increase of nickel in faeces in atopics compared to controls. This may indicate increased nickel absorption in atopics. There was also a positive correlation between nickel in urine and TIBC in atopics which may indicate an interesting therapeutic possibility to interfere with the nickel absorption