Nickel allergy

The most common sign of nickel allergy is inflammation of the skin at an area that comes into regular contact with nickel.[2] This often takes the form of a reddened patch of skin with raised bumps (papules) or small blisters (vesicles), and edema.[2] People with chronic dermatitis tend to have dry, scaly, and cracked skin at the site of contact.[2] These sites of inflammation (called "primary eruptions") can occur anywhere on the skin that contacts nickel, but are most common on the hands, face, or anywhere that contacts metal objects such as jewelry or metal clothes buttons.[2] Particularly high levels of nickel exposure can cause irritated patches of skin to appear at other sites on the body (called "secondary eruptions"). These typically occur as blistering rashes on the hands, eyelids, and at the inside of flexing joints (inside the elbow, back of the knee, etc.).[2]

Ingestion of nickel may cause a systemic reaction, which can result in generalized inflammation of the skin across the body, small blisters in the hands, irritation inside the flexing joints (flexural eczema), and redness and irritation of both buttocks.[2]

Systemic contact dermatitis (SCD) is defined as a dermatitis occurring in an epi-cutaneously contact-sensitized person when exposed to haptens systemically such as orally, per rectum, intravesically, transcutaneously, intrauterinely, intravenously, or by inhalation.[3]

The pathophysiology of systemic nickel allergy syndrome (SNAS) is not well understood. The clinical course is determined by an immunological interplay between two types of T cells (Th1 and Th2 responses). SCD is often considered a subset of SNAS, but with only skin manifestations.[4] SNAS presents with an array of symptoms ranging from respiratory to generalized skin rash to gastrointestinal symptoms.[5] The gastrointestinal symptoms may mimic those of irritable bowel syndrome.[1] A meta review evaluating SNAS found that 1% of patients sensitized to nickel reacted to the nickel content of a 'normal' diet, and with increasing doses of nickel more individuals reacted[6] SNAS is a multilayered immunological response demonstrating variance between individuals and doses of nickel exposure.

Nickel has a wide utility of application in manufactured metals because it is both strong and malleable, leading to ubiquitous presence and the potential for consumers to be in contact with it daily. However, for those who have the rash of allergic contact dermatitis (ACD) due to a nickel allergy, it can be a challenge to avoid. Foods, common kitchen utensils, cell phones, jewelry, and many other items may contain nickel and be a source of irritation due to the allergic reaction caused by the absorption of free released nickel through direct and prolonged contact. The most appropriate measure for nickel-allergic persons is to prevent contact with the allergen.

In 2011, researchers showed that applying a thin layer of glycerine emollient containing nanoparticles of either calcium carbonate or calcium phosphate on an isolated piece of pig skin (in vitro) and on the skin of mice (in vivo) prevents the penetration of nickel ions into the skin. The nanoparticles capture nickel ions by cation exchange, and remain on the surface of the skin, allowing them to be removed by simple washing with water. Approximately 11-fold fewer nanoparticles by mass are required to achieve the same efficacy as the chelating agent ethylenediamine tetraacetic acid. Using nanoparticles with diameters smaller than 500 nm in topical creams may be an effective way to limit the exposure to metal ions that can cause skin irritation'.[18]

Pre-emptive avoidance strategies (PEAS) might ultimately lower the sensitization rates of children who would develop ACD[19] It is theorized that prevention of exposure to nickel early on could reduce the number of those that are sensitive to nickel by one-quarter to one-third. Identification of the many sources of nickel is vital to understanding the nickel sensitization story, food like chocolate and fish, zippers, buttons, cell phones and even orthodontic braces and eyeglass frames might contain nickel. Items that contain sentimental value (heirlooms, wedding rings) could be treated with an enamel or rhodium plating.[20]

The Dermatitis Academy has created an educational website to provide more information about nickel, including information about prevention, exposure, sources, and general information about nickel allergy. These resources provide guidance in a prevention initiative for children worldwide.

Prevention of SNAS includes modifying dietary choices to avoid certain foods that are higher in nickel than others.[1]

Nickel allergy is typically diagnosed by patch testing – applying a patch with 2.5% (in North America) or 5% (in Europe) nickel sulfate to the upper back and looking for irritation on the skin.[2] As with other causes of allergic contact dermatitis, patches containing several common allergens are typically applied to the back for 48 hours, removed, then the spots examined for allergic reactions 2 to 5 days later.[21]

SNAS can often mimic IBS[1] and may be more common than is widely appreciated.[1] It therefore should be considered as a differential diagnosis item when a doctor is considering a diagnosis of IBS,[1] and nickel allergy testing is advisable as a means to exclude or confirm SNAS.[1] Even before such testing, some differentiating factors in the medical history are if certain foods prompt the symptoms (for example, peanuts or shellfish),[1] whereas IBS is not specific to those foods.[1]

Once a nickel allergy is detected, the best treatment is avoidance of nickel-releasing items. The top 13 categories that contain nickel include beauty accessories, eyeglasses, money, cigarettes, clothes, kitchen and household, electronics and office equipment, metal utensils, aliment, jewelry, batteries, orthodontic and dental appliances, and medical equipment.[22] Other than strict avoidance of items that release free nickel, there are other treatment options for reduction of exposure. The first step is to limit friction between skin and metallic items. Susceptible people may try to limit sweating while wearing nickel items, to reduce nickel release and thus decrease chances for developing sensitization or allergy. Another option is to shield electronics, metal devices, and tools with fabric, plastic, or acrylic coverings.[22]

There are dimethylglyoxime test kits that can be very helpful to check for nickel release from items prior to purchasing.[23] The American Contact Dermatitis Society 'find a provider' resource can help identify clinicians with training in providing guidance lists of safe items.[24] In addition to avoidance, healthcare providers may prescribe additional creams or medications to help relieve the skin reaction.

Nickel allergy is the most common contact allergy in industrialized countries, affecting around 8% to 19% of adults and 8% to 10% of children.[2] Women are affected 4–10 times as frequently as men.[2]

As nickel can be harmful to skin, its use in daily products must be regulated. A safety directive has been in place in Europe since 2004. Denmark in 1980, and then shortly after the European Union (EU), enacted legislation that limited the amount of free nickel in consumer products that come in contact with the skin. This resulted in significantly decreased rates of sensitization among Danish children 0 to 18 years of age from 24.8% to 9.2% between 1985 and 1998, with similar reductions in sensitization throughout the EU.[25][26]

No such directive exists in the United States, but efforts are under way to mandate safe use guidelines for nickel. In August 2015, the American Academy of Dermatology (AAD) adopted a nickel safety position paper.[27] The exact prevalence of Ni-ACD in the general population in the US is largely unknown. However, current estimates gauge that roughly 2.5 million US adults and 250,000 children have a nickel allergy, which costs an estimated $5.7 billion per year for treatment of symptoms.[28] Loma Linda University, Nickel Allergy Alliance, and Dermatitis Academy created the first open access self-reported patient registry to record nickel allergy prevalence data in the US.[ref 23]

In the 17th century, copper miners in Saxony, Germany, began to experience irritation caused by a "dark red ore". Since the substance, which would later be called nickel, led to many ailments, they believed it to be protected by "goblins", and called it "Goblin's Copper".[29] Josef Jadassohn described the first case of metal contact dermatitis in 1895, to a mercury-based therapeutic cream, and confirmed the cause by epi-cutaneous patch testing.[30] In the next century nickel began to be mass-produced for jewelry worldwide due to its cheap cost, resistance to corrosion and high supply.

In 1979 a large comprehensive study of healthy US volunteers found that 9% had been unknowingly sensitized to nickel.[31] As of 2008, that number has tripled.[32] Most importantly, nickel allergy among children is increasing, with an estimated 250,000 children sensitized to nickel.[33]

Published literature shows an exponential increase in reported nickel allergy cases.[34] The North American Contact Dermatitis Group (NACDG) patch tested 5,085 adults, presenting with eczema-like symptoms, showing 19.5% had a positive reaction to nickel.[35] Nickel allergy is also more prevalent in women (17.1%) than men (3%), possibly due to cultural norms related to jewelry and ear piercings and therefore increased exposure to nickel.[36] In order to investigate the current prevalence of nickel, Loma Linda University, Nickel Allergy Alliance, and Dermatitis Academy,[37] are conducting a self-reporting nickel allergy-dermatitis survey.[38]

• "Woman's metal allergy causes severe symptoms after knee replacement". ScienceDaily. December 16, 2014.