What Is Nickel Allergy?

Overview

Nickel allergy is one of the most common types of allergic contact dermatitis, an itchy rash caused by direct contact with a particular substance, such as nickel. It is estimated that nickel allergy affects more than 18% of people in North America. Notably, nickel allergy is far more common in people assigned to females at birth (AFAB) than people assigned to males at birth (AMAB), with an approximate population frequency of 10% in AFAB versus 2% in AMAB.¹  A potential explanation for this phenomenon is that nickel allergy commonly develops from wearing jewellery or piercings containing nickel, which people AFAB are more likely to wear. It may take repeated or prolonged exposure to develop an allergy to nickel. Sensitisation to nickel may correlate directly with the number of body piercings, suggesting that increased frequency of exposure increases the risk of developing a nickel allergy.¹  Consequently, it has been found that people with ear piercings are 3.2 times more likely to suffer from contact dermatitis to nickel.²

What is nickel?

Nickel is a metallic element that has a silvery-white, shiny appearance. It is the fifth most common element on Earth and can be found extensively in the Earth’s crust and core. It is naturally occurring in soil and water. Nickel is also an essential nutrient for some microorganisms, plants and animal species.³ 

In humans, a deficiency of nickel leads to reduced growth in intrauterine development, the progression of foetal growth and organ formation within the uterus during pregnancy, and also causes reduced iron absorption, resulting in anaemia. However, as nickel is abundant in nature and also present in almost all types of food, a deficiency in humans is rare.⁴

Additionally, nickel has excellent physical and chemical properties, such as resisting corrosion and heat; therefore, we commonly use it in many everyday items. The following items usually contain nickel:⁵

• Costume jewellery 
• Eyeglass frames
• Zippers and snap closures on clothing
• Coins
• Keys
• Batteries
• Instruments used in medicine
• Mobile phones
• Medical implants

Causes of nickel allergy

The exact mechanism of how nickel causes allergic contact dermatitis is unknown. However, it is known that allergic contact dermatitis is a T-cell-mediated delayed hypersensitivity response(reference). Nickel ions released from jewellery or other objects can penetrate the skin and activate epithelial cells that go on to produce various cytokines or chemokines. 

Cytokines are proteins released by immune cells and other cells (such as epithelial cells) in the body that act as chemical messengers in response to a pathogen, injury or, in this case, nickel and trigger an immune response. A key feature of immune responses is inflammation. 

Chemokines are cytokines that act as signals responsible for directing immune responses to the appropriate areas in your body to help fight an infection. The release of chemokines and cytokines causes a complex immune response, which leads to the activation of naive T-cells. 

Subsequent re-exposure to nickel leads to an activation of specific T-cells, causing a hypersensitivity reaction 48hrs to 72hrs after exposure.¹

Risk factors

Certain factors may increase your risk of developing a nickel allergy. These include the following.

Ear or other body piercings

As nickel is commonly used in jewellery, this increases your exposure to nickel. As mentioned above the rate of nickel allergy among persons with ear piercings is more than 3x as likely.²

Certain professions

If you are constantly exposed to nickel at work, your risk of developing an allergy is higher. Metalworkers, hairdressers, cashiers, cleaners, bartenders or other people working with money are more likely to develop an allergy. The risk is especially high when the exposure to nickel is in the presence of water or sweat, as this increases the risk of nickel corrosion and ions being released to be absorbed by the skin.³

A family history of nickel allergy

If other family members are sensitive to nickel, your chances of developing a nickel allergy also tend to be greater.

Allergy to other metals

If you are allergic to other metals, your chances of developing a nickel allergy also tend to be greater. 

People assigned male at birth (AMAB)

As mentioned above, people AFAB are more likely to suffer from a nickel allergy than people AMAB. This may be because people AFAB have more piercings and are more likely to wear jewellery, and they are more likely to come into contact with nickel-containing items such as certain shampoos, cosmetics and detergents.³

Age

The incidence of allergic contact dermatitis increases with age.⁶

Orthodontic patients

Nickel ions are released from orthodontic appliances in patients’ mouths when mixed with saliva, some foods and liquids due to corrosion leading to contact dermatitis.³

Orthopaedic implant patients

The prevalence of allergic contact dermatitis may be as high as 25% among patients who have an implant to fix a fracture or replace a damaged joint.²

Autoimmune conditions

People with autoimmune conditions such as systemic lupus or rheumatoid arthritis have an increased frequency of nickel allergy.¹

Hand dermatitis sufferers

People who suffer from hand dermatitis are more likely to suffer from nickel allergy, though the reason for this is unclear. It is speculated to be due to the regular handling of money.

Signs and symptoms

The symptoms of nickel allergy can range from mild to severe. Nickel allergy commonly presents as allergic contact dermatitis, with symptoms occurring between 48 to 72 hours after exposure. Common symptoms include:

• A rash or bumps on the skin
• Itching or burning
• Redness or skin discolouration
• Dry or rough patches
• Blisters and draining fluid in severe cases

If you suffer from a nickel allergy, the consumption of foods containing nickel can also lead to systemic contact dermatitis.⁷ This is when there has been no skin contact with nickel but involves ingestion or sometimes inhalation of the allergen, which can lead to a flare-up or worsening of dermatitis  if you have been previously sensitised due to direct skin contact.⁸

In severe cases of nickel allergy, you can develop systemic nickel allergy syndrome. Symptoms can include:⁷

• Headaches
• Chronic fatigue
• Abdominal symptoms such as nausea, vomiting, diarrhoea, bloating and pain
• Respiratory issues such as occupational asthma and rhinitis
• Cystitis
• Vulvovaginitis
• Urticaria (hives)
• Post-prandial dyspnea (shortness of breath after eating)
• Acne
• Iron deficiency anaemia

Management and treatment

There is no cure for nickel allergy, but avoiding contact with the metal will help prevent and reduce symptoms of allergic contact dermatitis.

Current treatments include the following.

Medication

Medications such as different creams, including corticosteroid creams help to decrease inflammation.  Soothing or moisturising lotions help ease the itching and restore the skin’s natural barrier.

Oral corticosteroids may be used briefly if the reaction is severe or the rash covers a large area.  Oral antihistamines may be used to relieve the itching.

Phototherapy

Phototherapy may be used when the allergy is severe or other treatments have not helped. This technique uses artificial ultraviolet light to treat the skin. However, months of treatment may be necessary before significant improvements can be observed.

Non-medical advice

It is also important for patients to avoid scratching the affected area as it can lead to wounds and scarring and increase the risk of infection. 

Living with a nickel allergy

According to dermatologists, people who have been diagnosed with a nickel allergy should do the following to avoid exposure and reduce symptoms.

Take care with jewellery

Choose nickel-free jewellery, hypoallergenic, or made from metals such as surgical-grade stainless steel, 18-, 22-, or 24-karat yellow gold, pure sterling silver, or platinum. Watchbands should also be made of leather, cloth or plastic.

Scrutinise your clothing

Belt buckles, bra hooks, metal buttons, zippers and snaps may contain nickel. If your clothing has these, replace them with plastic or plastic-coated ones. You can also create a barrier between these items and your skin by coating the items with clear nail polish. However, this will need to be re-applied often.

Cover electronic devices

Some devices, including cell phones, laptops, and tablets, may contain nickel. To avoid exposure, use a protective cover.

Use nickel-free household objects

Some household objects may contain nickel. Swap these for some made of other materials. Examples include brass keys, pots and pans with silicone handles, and titanium or plastic eyeglass frames.

Avoid foods containing nickel

If you are extremely sensitive to nickel, avoid foods that are routinely high in nickel content. 

These include:

• Soy products such as soybeans, soy sauce, and tofu
• Licorice
• Buckwheat 
• Cocoa powder and chocolate
• Clams
• Various nuts, such as cashews
• Figs
• Oatmeal
• Legumes⁶

Diagnosis

A doctor diagnoses nickel allergy by asking about your symptoms, taking into consideration your medical history, and asking about any recent contact with items containing nickel. If nickel allergy is suspected, it can be confirmed using a patch test, where small quantities of allergens are applied to the skin and covered with patches. If you are allergic to nickel, the skin under the patch will be red after the patch is removed several days later 

Other causes for allergic contact dermatitis (such as plants, cosmetics, and detergents), and fungal infections need to be considered. Underlying inflammatory diseases, such as psoriasis, lupus, and ulcerative colitis, should also be ruled out, as these can mimic and increase the risk of allergic contact dermatitis due to nickel allergy.⁶

Summary

Nickel can be found in many everyday items, including jewellery, medical devices, and even some foods. Some people, especially those in certain professions, with frequent or prolonged exposure may develop an allergy to nickel. This usually presents itself as allergic contact dermatitis. Patients with orthodontic or orthopaedic implants containing nickel are also at a higher risk of developing an allergy to the metal. If you suffer from an itchy rash after coming into contact with nickel, you should contact your doctor to confirm a diagnosis. People diagnosed with a nickel allergy should avoid contact with nickel by swapping items such as jewellery or keys containing nickel for nickel-free substitutes and avoid foods high in nickel content, such as cocoa powder. As there is no cure for nickel allergy, in those cases where you cannot avoid nickel,  medications such as corticosteroids, creams, and antihistamines can help alleviate symptoms.