A spot test for detection of cobalt release - early experience and findings

Nickel and cobalt release from jewellery and metal clothing items in Korea

BACKGROUND

In Korea, the prevalence of nickel allergy has shown a sharply increasing trend. Cobalt contact allergy is often associated with concomitant reactions to nickel, and is more common in Korea than in western countries.

OBJECTIVE

The aim of the present study was to investigate the prevalence of items that release nickel and cobalt on the Korean market.

MATERIALS AND METHODS

A total of 471 items that included 193 branded jewellery, 202 non-branded jewellery and 76 metal clothing items were sampled and studied with a dimethylglyoxime (DMG) test and a cobalt spot test to detect nickel and cobalt release, respectively.

RESULTS

Nickel release was detected in 47.8% of the tested items. The positive rates in the DMG test were 12.4% for the branded jewellery, 70.8% for the non-branded jewellery, and 76.3% for the metal clothing items. Cobalt release was found in 6.2% of items. Among the types of jewellery, belts and hair pins showed higher positive rates in both the DMG test and the cobalt spot test.

CONCLUSION

Our study shows that the prevalence of items that release nickel or cobalt among jewellery and metal clothing items is high in Korea.

Consumer leather exposure: an unrecognized cause of cobalt sensitization

BACKGROUND

A patient who had suffered from persistent generalized dermatitis for 7 years was diagnosed with cobalt sensitization, and his leather couch was suspected as the culprit, owing to the clinical presentation mimicking allergic chromium dermatitis resulting from leather furniture exposure.

MATERIALS AND METHODS

The cobalt spot test, X-ray fluorescence, inductively coupled plasma mass spectrometry and scanning electron microscopy were used to determine cobalt content and release from the leather couch that caused the dermatitis and from 14 randomly collected samples of furniture leather.

RESULTS

The sample from the patient's leather couch, but none of the 14 random leather samples, released cobalt in high concentrations. Dermatitis cleared when the patient stopped using his couch.

CONCLUSIONS

Cobalt is used in the so-called pre-metallized dyeing of leather products. Repeated studies have found high levels of cobalt sensitization, but not nickel sensitization, in patients with foot dermatitis. We raise the possibility that cobalt may be widely released from leather items, and advise dermatologists to consider this in patients with positive cobalt patch test reactions.

The cost of nickel allergy: a global investigation of coin composition and nickel and cobalt release

BACKGROUND

Nickel is widely used in coins; nickel may cause contact allergy and allergic contact dermatitis in those who handle them.

OBJECTIVES

To investigate alloy use, coin composition and nickel and cobalt release for a worldwide selection of currently circulating coins.

MATERIALS AND METHODS

Eight hundred and fifty coins of 361 different denominations or issues from 52 countries were collected and analysed with X-ray fluorescence spectrometry and nickel and cobalt spot tests.

RESULTS

Copper-nickel was the most frequently identified coin alloy, being observed in 100 denominations (28%), followed by aluminium-bronze (62, 17%). In total, 239 denominations released nickel (28%). Coins from Bolivia, Brazil and Costa Rica did not release nickel. Fewer than one-third of the denominations or issues from China, India, the euro area and Indonesia released nickel. In the United States, the Russian Federation, Japan, and Mexico, one-third or more of the denominations released nickel.

CONCLUSIONS

This worldwide selection of circulating coins covered countries with 75% of the world population, and shows that the majority of the world population lives in countries where coins release nickel. Pertinently, ∼ 40% of circulating coin denominations do not release nickel.

Assessment of nickel and cobalt release from 200 unused hand-held work tools for sale in Denmark - Sources of occupational metal contact dermatitis?

INTRODUCTION

Nickel and cobalt allergy remain frequent in dermatitis patients. It is important to determine possible nickel and cobalt exposures at work as these may offer important information to regulators and physicians who perform patch testing. Clinical relevance of metal exposure is usually assessed by the treating physician via the medical history and by presentation of allergic contact dermatitis.

OBJECTIVES

To screen unused non-powered hand-held work tools for nickel and cobalt release by using colorimetric spot tests.

MATERIALS & METHODS

A random selection of 200 non-powered hand-held work tools for sale in 2 retailers of home improvement and construction products were analyzed qualitatively for metal release using the colorimetric nickel and cobalt spot tests.

RESULTS

Nickel release was identified from 5% of 200 work tools using the dimethylglyoxime (DMG) test. In 8 of 10, positive results were located to the metal ring that acts like a cuff and is located at the end of the grip. The positive DMG test results were not related to specific categories of work tools. The cobalt spot test gave no positive test reactions.

CONCLUSIONS

It appears that the proportion of work tools that release nickel, in amounts that may result in allergic nickel dermatitis, has decreased markedly, when results were compared with a Swedish study performed more than a decade ago. No cobalt release was detected but it should be underscored that hard-metal tools were not examined. Other sources of cobalt may explain the relatively high levels of cobalt allergy in dermatitis patients.

Hand eczema guidelines based on the Danish guidelines for the diagnosis and treatment of hand eczema

BACKGROUND

Classification of hand eczema has traditionally been based both on aetiology and clinical appearance. For 20% of cases, the aetiology is unknown.

OBJECTIVES

To suggest a classification based on well-defined aetiology as well as on predefined clinical patterns and on the dynamics of hand eczema.

METHODS

Literature studies and discussions among members of the Danish Contact Dermatitis Group.

RESULTS

Criteria are given for the aetiological diagnoses of allergic contact dermatitis of the hands, irritant contact dermatitis of the hands, protein contact dermatitis of the hands, atopic hand eczema and aetiologically unclassifiable hand eczema. Six different clinical patterns are described and illustrated. Suggestions for general treatment principles are given.

CONCLUSION

Operational guidelines for the diagnosis and treatment of hand eczema are described.

Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?

BACKGROUND

Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure.

OBJECTIVES

The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery.

METHODS

The cobalt spot test was used to assess cobalt release from all items. Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS).

RESULTS

Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin-cobalt plating on these.

CONCLUSIONS

This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future. Industries may not be fully aware of the potential cobalt allergy problem.