If there’s one metal that you cannot live without on a daily basis, it’s nickel. It’s present in your jewelry, currency, clothes, and even food. A silvery-white lustrous metal with a golden tinge, nickel is hard and ductile and is slow to react with air and oxidize, making it highly corrosion resistant. It’s a very useful metal but the widespread use of it has resulted in an increase in nickel allergies. One of the most common causes of contact dermatitis in the US, particularly affecting women, the prevalence of nickel allergy is found to be closely linked to the popularity of ear piercing.1
The allergy or contact dermatitis is noticed when the body comes in contact with nickel-containing metal or food or the metal is inhaled in some form. The itchy rashes or eczema that develop from contact with nickel is mostly noticed on the earlobes (due to earrings), wrist (watch), and abdomen (jeans stud).2
This nickel sensitivity could be instant and may develop after your first exposure to nickel or after prolonged use. Nickel allergy affects women three to 10 times more than men. This is because of the daily contact with the allergen in the form of jewelry, garments, etc.3
The exact cause of nickel allergy is not known. It is believed that the sensitivity may be inherited, too. Though often associated with earrings and other jewelry, nickel is also found in many other everyday items.
Here is a lowdown on all things nickel.
Things That Cause Nickel Allergy
Nickel Jewelry
One of the most common sources of nickel allergy is jewelry. Contact with nickel-containing jewelry is believed to induce nickel sensitivity. Ear piercing and wearing cheap jewelry put you in close contact with the metal, leading to nickel allergy.
In a study where 960 schoolgirls were investigated to study the frequency of ear piercing and the prevalence of nickel and cobalt allergy, the results showed that the prevalence of nickel allergy was 13 percent among girls with pierced ears as against just 1 percent among girls with no piercing. The study thus shows a strong relationship between ear piercing and initiation of nickel allergy.4
Though nickel allergy is widely believed to be more of a girl thing and studies like the one above provide enough reasons to believe so, with the increased use of earrings among young boys and men, ear piercing is no more the only reason why women are more susceptible to nickel allergy. Research suggests women could be easier to sensitize than men.5
Paper Currency, Coins
Nickel is widely used in making coins. Even though many coins are manufactured in keeping with nickel regulations, it has been found that the coins often get contaminated with nickel from various sources. Even paper currency has shown nickel contamination. This nickel gets released onto the skin during coin handling, triggering an allergy.6 Moreover, it has been found that only five minutes of intense handling of coins is enough to release nickel onto the skin.7
When nickel release from used coinage from the UK, Sweden, and France was studied, it was seen that nickel ions are readily available on the coin surface. When these were treated with artificial sweat, approximately 2 μg of nickel per coin was extracted from cupro-nickel coins. After one week in artificial sweat, approximately 30 μg/cm2 was released from them. Theoretically, several micrograms of nickel salts may be transferred daily onto our hands by the intense handling of high-nickel-releasing coins.8
Nickel Silver Keys
Compared to keys made of brass, keys made from nickel silver are stronger and durable. Nickel silver is considered to be one of the strongest materials to make key blanks from. Studies, however, show that nickel silver causes positive patch-test reactions9 for nickel. One way of avoiding nickel exposure is to have an enamel coating on keys but it’s not a sustainable solution since consistent use can reduce the effect of the enamel.10
Metallic Cell Phone Covers
Metal allergens, especially nickel and chromium, are often implicated in mobile phone-associated allergic contact dermatitis (ACD).11 Before we delve into how cell phones can cause allergies in some people, a clarification is needed here. Cell phones by themselves do not cause contact allergies. It is the metallic phone casings that are invariably the culprit. However, with the trend towards metallic mobile phone casings and the high incidence of nickel sensitization among users, the incidence of mobile phone contact dermatitis is increasing. In a study of a 39-year-old man with a six-month history of dermatitis that didn’t go with treatment, his continuous use of cell phone was found to be the culprit.12
Eyeglass Frames, Paper Clips, And Pens
Eyeglass frames are made mostly with polyvinyl chloride (PVC) or titanium. While both these are generally hypoallergenic, there are instances where titanium alloys contain traces of nickel from the production process. Studies, where facial dermatitis was investigated, showed incidences of nickel allergy caused by metal spectacle frames. Of the total 507 facial dermatitis cases that were studied in Taiwan, 56 percent of the nickel-positive cases were caused by metal spectacle frames.13 Paper clips and pens with nickel alloys can also result in contact dermatitis. The exclusive steel pens and the common steel paper clips can easily be avoided for non-metal ones, thus dodging the risk of an allergic reaction.
Orthodontic Braces
In orthodontics, nickel is considered to be one of the most common metals causing contact dermatitis. Stainless steel and nickel titanium are the most widely used nickel-alloys in orthodontic appliances. Though stainless steel contains lower nickel content (8 percent), nickel titanium has over 50 percent nickel in it.14 Stainless steel orthodontic equipment and components are therefore less likely to cause nickel hypersensitivity. However, there are exceptions and studies have shown that some types of stainless steels release enough nickel to cause allergies.15
Certain brands of orthodontic wires made from nickel-titanium alloy are believed to potentially have a high enough nickel content to cause allergic reactions in the mouth.16
Stainless Steel Utensils
When properly chosen, stainless steels are durable, do not affect the taste of the product, and are easy to clean and sterilize to prevent bacterial contamination of food. However, high-quality stainless steel in cooking utensils may release enough nickel to provoke dermatitis in sensitized people. Sweat, household detergents, and acidic fruits and vegetables tend to accelerate this nickel release significantly.17 However, the amount of nickel derived from these cooking utensils was found to be negligible—less than that found in one piece of a chocolate bar. New pans, when used with acidic fruits, showed more nickel release but even that was only one-fifth of the normal intake of an average person.18
Cleaning Products
Consumer products like detergents and cleaning products are a minor source of contact with nickel. Studies show that the nickel traces found in these products and the exposure to nickel from them are not high enough to sensitize a person to nickel.19
Jeans Buttons
Clothing fasteners like buckles and jeans buttons made from nickel are a common cause of contact dermatitis, especially on the skin around the abdomen. A study has shown that it is experienced more while wearing new jeans and the effect begins to wear off with each wash. In the case of new jeans, a good coating of nail enamel (that will stay on for two washes) on the button can prevent nickel from coming in direct contact with the skin.20
Nickel In Food
Small amounts of nickel are also found in many foods, including grains, fruits, and vegetables. But could you be allergic to it?
Foods such as grains and bread, roots and vegetables, cocoa and chocolate, soya beans, nuts and legumes have very high nickel content. Of these, vegetables probably contain more nickel than other food items. Consuming these foods in larger amounts may increase the nickel intake to 900 μg/person/day or more21, which may lead to a flare-up of hand eczema in nickel-sensitive patients.22
How Do You Detect Nickel Allergy?
Nickel allergy signs and symptoms include:23
- Rash or bumps on the skin
- Itching, which may be severe
- Erythema or redness or changes in skin color
- Lichenification (thickened or leathery skin) of hands and contact areas
- Eczema
- Blisters and draining fluid in severe cases
These symptoms can range from mild to severe. They can also appear soon after the contact with nickel or take a few hours to a few days to show up. Some studies conclude that ingestion of small amounts of nickel may be more detrimental in persisting eczema than external contact with nickel.24
Is There A Way Out?
Nickel contact dermatitis, particularly in patients with chronic hand eczema, can lead to an inability to work, a decrease in quality of life, and significant healthcare expenses. The only way for those with nickel allergy to avoid a recurrence of the reaction is to not come in contact with nickel-containing products. Another option is to use antiperspirants that will reduce sweating, and subsequently the trigger for allergy. You can even apply a thin layer of glycerine emollient or some such barrier creams on the skin.25
Chelation therapy with disulfiram is another therapeutic option in nickel-allergic patients with systemic contact dermatitis. Hyposensitization therapy has also been attempted with some success in systemic contact dermatitis caused by nickel and Parthenium hysterophorus.26
How To Avoid Exposure To Nickel?
All said and done, nothing can ensure safety from nickel allergy like a good regulation. Current good manufacturing practices ensure that trace nickel, cobalt and chromium concentrations in consumer products are less than 5 ppm (parts per million) of each metal. If this can be accepted as a standard for maximum concentrations and the target to achieve concentrations be set as low as 1 ppm,27, it will further reduce nickel contact allergies. This is evident in Europe where regulations have ensured a decrease in the prevalence of nickel allergy, whereas, in North America, nickel allergic contact dermatitis is on the rise.28
So, if you have the allergy, you might want to stay away from a lot of objects mentioned above. With alternatives available in the market for everything, it shouldn’t be difficult.
References
