The January 2013 Volume of the Contact Dermatitis journal is all about nickel allergy resulting from handling coins. It seems that not much attention is given to this particular source of nickel allergy for two main reasons:

1. Manufacturers claim that there is no way around nickel in coins; it is cheap, easy to stamp, resists corrosion and prevents coin fraud.
2. Unlike jewelry and belts containing nickel, the time spent actually holding coins is too short to cause an allergic reaction anyway.

But dermatologists come across hand eczema caused by handling coins, especially in cashiers.  One group of scientists reviewed literature from 1900 to 2012, while another evaluated nickel content of coins from 52 countries. Combined, the studies in this issue of the journal make a few good points:

Nickel allergy affects about twice as much women as men, but this can be due to other factors, not just handling coins.

There are regulations for how much nickel can be present in various products; a certain level should not be exceeded. But these regulations do not make it clear whether these levels cause a skin reaction in the short term or the long term, or through cumulative effect.

World map showing the proportions of coins releasing nickle. Dark pink indicates large amount; pink indicates intermediate; light pink indicates minor; green indicates no nickel; grey indicates unknown (source in sources).

Coin handling is considered short term, except for those who actually work with coins. It was found that people in this group who developed hand eczema improved greatly about four weeks after ceasing contact with coins.

It is true that prolonged exposure to nickel, as seen with jewelry, is more likely to elicit a reaction compared to shorter periods of exposure, but repeated exposure actually causes a cumulative effect. This means that there might be no reaction after one, two, or more times handling coins, but that eventually a sensitization occurs, and the symptoms of eczema start.

The amount of nickel released from coins increases when the hand is sweaty and warm.

Some countries do currently manufacture coins that do not release nickel, as seen in the map shown (authors of this particular study believe this illustration might be a slight underestimation of nickel-releasing coins, due to the specifications of the test used to detect nickel release).

Perhaps the cost of making a change from using nickel to another metal should be measured against the cost of eczema in terms of cost of treatment and working hours lost during sickness, as well as patient distress and decreased quality of life.

Thank you for reading!

Sources:

JP. Thyssen et al. Coin Exposure may Cause Allergic Nickel Dermatitis: a Review. Contact Dermatitis 2013; 68 (1): 3-14.

C. Liden et al. Is there a Flip Side to Nickel Use in Coins? Contact Dermatitis 2013; 68 (1): 1-2.

CR. Hamann et al. The Cost of Nickel Allergy: a Global Investigation of Coin Compostion and Nickle and Cobalt Release. Contact Dermatitis 2013; 68 (1): 15-22. (also source of map)