AncestryDNA Traits
Does your skin get irritated when you wear a certain watch or pair of earrings? If you've ever found yourself with red, inflamed skin that's been in contact with specific pieces of jewelry, watches, belts, or even your phone, there's a chance your immune system is trying to protect you from metal ions.
This metal sensitivity can have a genetic component, and an AncestryDNA + Traits test can reveal if you have the genetic markers for it.
How Do You Know If You Are Allergic to Metal?
If you tend to get itchy after touching metal, you may be allergic to it. You might have noticed a reaction to a ring or necklace, or even to the metal rivet on your jeans when it's next to your skin.
Sensitivity occurs when your body has an immunological response to absorbed metals. It can eventually become a hypersensitivity, or allergy, with repeated exposure.
People with a metal allergy develop an itchy, red rash (contact dermatitis). Most commonly, nickel, chromium, or cobalt is the culprit.
- An estimated 15% to 16% of women and 4% to 5% of men are allergic to nickel.
- Chromium allergies are less common, affecting an estimated 5% to 10% of the population.
- Cobalt allergies affect approximately 2% of the population.
There's significant overlap between nickel and cobalt allergies, with approximately 25% of those with nickel allergies also reacting to cobalt.
How Do Genetics Relate to a Metal Allergy?
AncestryDNA scientists asked over 430,000 people, "Have you ever had a reaction to metal touching your skin, like metal jewelry?" and compared their answers with their DNA profiles. Based on these data, they connected over 475 DNA markers to developing a metal allergy.
The Ancestry scientists used these results to develop a statistical tool known as a polygenic risk score, which estimates the likelihood that someone may have a certain trait based on their DNA. In this case, they found that only 3% of the variation in whether people developed a metal sensitivity could be attributed to difference in their DNA. Environmental factors, like how frequent and intense your exposure to these metals, has a large influence on whether you develop a metal allergy.
What Else Influences Allergic Reactions to Metals?
Having ear or body piercings can increase the likelihood of developing a metal allergy. One meta-study revealed a consistent association between an allergic reaction to nickel and piercings. This is likely due to increased nickel exposure over time. Piercings may release tiny amounts of nickel over time, which can increase sensitization or trigger reactions. It may also explain why women have a higher prevalence of metal allergies than men, since women wear piercings more often.
Occupational exposure to metals can also cause hypersensitization. In fact, one analysis of over 41,000 patients with contact dermatitis found that approximately 17% of those with a sensitivity to cobalt had some sort of occupational link. Beyond belts and jewelry, cement, concrete, and mortar were commonly cited sources of exposure.
Allergic reactions to metals tend to develop over time with repeated exposures. Those repeated exposures can also increase the severity of the reaction, leading to more significant inflammation or chronic dermatitis.
Other Sources of Metal Exposure That May Cause an Allergic Reaction
Some people with metal sensitivities may react to trace metals in food. Consuming small amounts of nickel, chromium, or cobalt usually doesn't trigger a reaction. In fact, cobalt is a key component of vitamin B12 and is necessary for health. But some people may benefit from limiting or removing certain foods from their diets.
These foods tend to be higher in nickel:
- Wheat and oats
- Seafood
- Legumes like chickpeas, lentils, peanuts, and soybeans
- Green vegetables
- Fruits like figs, pineapples, prunes, and raspberries
- Chocolate and other cocoa-rich foods
Foods higher in chromium include:
- Beef
- Eggs
- Oysters
- Broccoli
- Coffee
- Beans
In addition to the foods listed above, people with a cobalt metal sensitivity may want to avoid nuts, apricots, and whole-grain flour, in addition to the foods listed above.
Metal sensitivities and allergies also matter in the medical field. Nickel, cobalt, and chromium are commonly used in implants for joint replacements, screws, and plates. Some hypersensitive people could react poorly to these materials and may require hypoallergenic equipment.
Ready to learn what your genes say about you? Take an AncestryDNA + Traits test to discover if your genes predispose you to allergies and sensitivities to metal, dairy, alcohol, and more. If you've already taken a test, review your results with an Ancestry subscription.
