Palladium allergy: a frequent sensitisation

Prevalence of contact allergy to metals: nickel, palladium, and cobalt in Southern Sweden from 1995-2016

BACKGROUND

In 2001, the EU nickel directive was introduced to prevent contact allergy to nickel. Contact allergy to palladium and/or cobalt is often seen together with contact allergy to nickel.

OBJECTIVES

To compare the contact allergy prevalence of nickel, palladium, and cobalt allergy before and after the introduction of the EU nickel directive in consecutive patients with dermatitis.

METHODS

A retrospective analysis of patch test results from 1995-2016 was performed (n = 18 264). Chi-square tests were used to examine trends for nickel, palladium, and cobalt across test years. Logistic regression was used for associations.

RESULTS

The prevalence of nickel allergy decreased significantly in the youngest age group (6-30 years) for both female and male patients from 1995-1999 to 2012-2016: females: 33.4% to 19.1% (P < .001); males: 5.9% to 2.1% (P < .05). The concomitant reactions between nickel and palladium and nickel and cobalt among young females, respectively, also decreased significantly. Isolated palladium and cobalt allergy remained stable (1.4% and 2.3%, respectively) during the same time period for both men and women.

CONCLUSIONS

The prevalence of nickel has decreased among young females and males suspected of contact allergy in Southern Sweden after the introduction of the EU nickel directive. There has been no change in isolated palladium or cobalt allergy.

Metal allergy--a review on exposures, penetration, genetics, prevalence, and clinical implications

The prevalence of metal allergy is high in the general population, and it is estimated that up to 17% of women and 3% of men are allergic to nickel and that 1-3% are allergic to cobalt and chromium. Among dermatitis patients, the prevalence of metal allergy is even higher. Metal allergy is mainly an environmental disorder although null mutations in the filaggrin gene complex were recently found to be associated with nickel allergy and dermatitis. Environmental metal exposures include jewelry, buttons, clothing fasteners, dental restorations, mobile phones, and leather. Although consumer exposure is responsible for most cases of metal allergy, the importance of occupational metal exposure remains present and should always be taken into consideration when one interprets allergic patch test reactions to metals. Traditionally, nickel, cobalt, and chromium have been the most important contact allergens. However, recently, gold and palladium have drawn much attention as the prevalence of contact allergy to these metals is high. Palladium allergy is mainly a result of cross-sensitization to nickel, whereas gold allergy is rarely clinically relevant when one takes its high prevalence into account. The epidemiology of metal allergy has recently changed in Europe as nickel allergy among ear-pierced Danish women has decreased following regulatory intervention on nickel release from consumer products. In the United States, the prevalence of nickel allergy is still increasing, which may be explained by the absence of regulation. The prevalence of chromium allergy is increasing in the United States, Singapore, and Denmark among dermatitis patients. This increase is significantly associated with leather exposure in Denmark. Metal allergy may result in allergic contact dermatitis and systemic allergic (contact) dermatitis. Furthermore, metal allergy has been associated with device failure following insertion of intracoronary stents, hip and knee prostheses, as well as other implants. This area is in need of more research.