Nickel Allergy: Causes, Symptoms, and Caution

Nickel allergy, also known as nickel contact dermatitis (Ni-ACD) is a type of dermatological reaction that, as its name suggests, arises from contact with materials containing this chemical element. Contact allergies occur in up to 20% of the general population, with nickel being the most common topical allergen of all.

The prevalence in Europe is 8-19% of the adult population, while young children only develop these reactions in 10% of cases. As the physiological bases of allergic dermatitis are related to repeated exposure to a specific compound, it is difficult for an infant to develop it in the first years of life.

Metals such as gold (Au), silver (Ag), mercury (Hg), nickel (Ni), copper (Cu), cobalt (Co) and many others are distributed in our environment. Therefore, it is not surprising to learn that up to 15% of the world's population suffers from metal contact dermatitis. If you want to know everything about nickel allergy, read on.

What is a nickel allergy?

As indicated by the portal Statpearls, Allergic contact dermatitis (ACD) is the most common occupational skin condition. This type of reaction is classic from a physiological point of view, since it is mediated by T lymphocytes, occurs in a delayed manner, and is a response to an exogenous agent.

Nickel penetrates the skin of those who come in contact with it, which activates keratinocytes, the most predominant cells in the epidermis. This results in a specialization of cytokine-releasing T cells, the action of which is usually based on local inflammation and the activation of other immune bodies.

In summary, cascade reactions after exposure to antigen (nickel) they warn T lymphocytes, which multiply, travel to the site of exposure and cause a rash. Anyway, sensitization to this antigen requires previous exposures so that the immune system can recognize it, so it doesn't develop right away.

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What causes it?

To understand the causes of nickel allergy we must go to epidemiological studies. As indicated by the dermatological portal Dovepress, the general prevalence is 8.6%, while in women this value increases to 17%. Other studies face data of 2% in men and 10% in women.

With these figures you can imagine what nickel allergies are usually due to. With the help of the aforementioned portal and others we collect some of the most common causes of this contact dermatitis.

1. Jewelry and consumer products

Earrings are the most common cause of nickel sensitization. About 81% of women who are positive for this sensitivity wear or have worn earrings at some point.

For this reason, in 1990 Denmark (and later the European Union) established a limit of 0.5 micrograms / square centimeter / week of nickel release in any alloy for human use. Thanks to these directives, the prevalence of nickel allergy has decreased, although it remains very important.

2. Exposure in the workplace

Sources already cited estimate the prevalence of occupational contact allergy to metals in almost 40% of workers in certain sectors. The more the patient is exposed to metal, the more likely they are to develop sensitization.

Nickel allergy is associated with the use of certain tools. These can release compounds that even bypass gloves, thus allowing haptens to come into contact with the skin. According to some studies, up to 40% of nickel allergy patients in the workplace develop eczema on the hand.

3. Genetic predisposition

Although it is difficult to establish direct causality, it seems that Having a family history of nickel allergy can contribute to its onset. On the other hand, sensitivity to other metals tends to make the disorder appear more easily.

Nickel allergy symptoms

Symptoms can be mild or severe, to the point that the occupational capacity of the patient is impossible. The shape of the rash at the nickel contact area follows the nature of eczema, being red, itchy, scaly, and crusty. The reaction tends to be local, in the specific place of exposure.

As indicated by the portal DermNet NZ, there is a debate about whether reactions can appear in areas that have not been in contact with metal. Rashes may develop in areas far from the contact site, but the exact causes behind this event are not known.

Diagnosis and treatment

As the Mayo Clinic indicates, sometimes a physical examination and anamnesis (questions to the patient) are sufficient. In certain cases, establishing causality is simple: if the person develops the local rash after being in contact with nickel, the thing is quite clear.

Unfortunately, sometimes rashes appear without any apparent cause. On these occasions it is necessary to go to patch tests, which are based on the application of very small doses of suspected allergens to be later covered. If you are allergic to any metal, it will be easy to record the local reaction by the allergist.

The treatment involves trying not to come into contact with materials with nickel in any moment. If this is not possible or is done accidentally, corticosteroid creams (or their oral variants) may be prescribed to the patient to alleviate the local reaction.

On the other hand, Oral antihistamines may also be necessary. They relieve itching a lot, since they work by inhibiting histamine, an essential compound for allergic responses to occur.

Examples of materials with nickel

According to the portal Ecarf, nickel is virtually everywhere. We are going to list a series of materials and elements of daily use that contain it, but you must bear in mind that almost any surface with a metallic tone can have it.

Among the many examples we find the following:

• Piercings and pending: As we have said, these are the main cause of nickel allergy. The tissue of the ear gradually corrodes the metal, which releases the haptens that promote the immune reaction and sensitivity.
• Other types of jewelry: necklaces, bracelets, earrings, bracelets, rings and a host of other metal accessories.
• Glasses: some eyeglasses contain nickel in their frames. If you are allergic to this metal, discuss it with your ophthalmologist before purchasing one.
• Items for daily use: Coins, keys, watches, and cell phones can carry nickel. Unfortunately, it is very difficult to avoid contact with most of them.
• Compounds present in the work area: Batteries, metal plates, car motors, tools, and a host of other work materials have nickel.

Nickel and diet

It should also be noted that there are many foods rich in nickel. Potatoes, spinach, nuts, teas, chocolates, soybeans, coffee and other foods have a high concentration of this metal. If a patient does not respond to normal treatments, the allergy may be suspected to stem from the diet.

Anyway, there are controversies regarding this issue. The amount of nickel that is usually consumed daily is 200 micrograms, while it has been shown that sensitive patients do not usually respond to less than 5000 micrograms in a single dose.

Thus, it is not at all clear whether dietary changes could help to cope with a nickel allergy. However, if the patient is very sensitive to metal, the medical professional may recommend that they stay away from certain products.

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If you are allergic to nickel, look for alternatives

If you are allergic to nickel, all you have to do is stay away from metal objects that come into contact with your skin, like watches, earrings, piercings, necklaces and bracelets. This does not mean that you should refrain from wearing body accessories, as there are rubber and fabric accessories, for example.

If you work in the workplace with tools that may contain nickel, you may need to change work materials or you may need a series of special protections. Discuss with your doctor the options available, because the more you expose yourself, the worse the successive reactions will be.