What is metal allergy?

Metal allergy is a late type allergic reaction in which the immune system gives rise to chemicals such as metals. In the 20th century, industrialization and modern life led to an extreme skin sensitivity to metals and thus an increase in metal allergy. There is a general focus on nickel, cobalt and chromium as these metals are the most common. Metals such as nickel, cobalt and chromium are everywhere in our environment.

In the first half of the century, nickel allergy and contact dermatitis started to be more common among people working in the metal and plating industry. Nickel allergy, which we encounter most often when metal allergy is mentioned today, is mostly explained by exposure to nickel-containing consumer products.

It is estimated that metal allergy is high in the general population, 17% of women and 3% of men have nickel allergies. In addition, cobalt and chromium allergy can be seen between 1-3%. Allergies to new metals such as titanium have also been shown in recent rotation. This rate is higher in patients with dermatitis complaints.

What Are The Most Common Metal Allergies?

Nowadays, metal items and chemical substances, which are increasing day by day with industrialization, lead to the development of new allergic reactions.

Nickel, cobalt and chromium are the most commonly used metals, so they are the most emphasized.

Allergic complaints about titanium, which has been used more in recent years, have started to be published. It is seen that titanium allergies will increase especially with the use of titanium in implants.

Titanium

Although titanium allergy is not generally known, it has reported that approximately 4% of all patients will be allergic. Symptoms can be very different and variable in people with titanium allergy. These can range from simple skin rashes to contact dermatitis or muscle soreness and chronic fatigue.

Titanium (Ti) exposure in implants and titanium used as nanoparticles (NP) from personal care products are the most common causes of titanium allergy.

Although titanium dioxide (TiO 2) can trigger allergies in some people, it is widely used in consumer products because it is non-toxic. It is known as “pearl agent” because it makes paper and paint shiny and white. For titanium dioxide, it may be in the content of foodstuffs, pills and cosmetics, especially titanium-containing products

Orthopedic and Surgical Implants

Dentistry: As colored pigment in dental implants and composites.

Sunscreen ingredients: Fine titanium dioxide blocks harmful ultraviolet rays from the sun.

Sweets: Makes candy appear brighter and can be found in chewing gum, for example.

Cosmetics: Used to brighten and intensify the makeup color. It is regularly found in eyeshadows, blushes, nail polish, lotions, lipsticks, and powders.

Toothpaste: Used as a pigment substance to make toothpaste whiter.

Paint: TiO 2 improves the durability of coatings and gives a white color.

Plastic carrier bags: Increases durability and gives a white color.

Medical pills and vitamin supplements can also take the white coating from titanium dioxide.

Piercing and Jewelry: can be found in watches and all kinds of body piercing items.

It seems that many people’s exposure to Titanium comes predominantly from dental and medical implants, personal care products, and foods. Although Ti is considered to be highly biocompatible compared to other metals, titanium, particularly in dental implants, can possibly be released into biological fluids and tissues under certain conditions.

In most studies, titanium does not penetrate the skin barrier in the form of nanoparticles such as pure Ti, alloy or Ti oxide. However, signs of Ti penetration in the oral mucosa were seen.

Patch testing with existing Ti preparations for detecting type IV hypersensitivity is currently insufficient for Ti. Although several other methods have been proposed for contact allergy detection, including lymphocyte stimulation tests, it has not yet gained general acceptance and the diagnosis of Ti allergy is primarily based on clinical evaluation.

The diagnosis of Ti allergy is primarily based on clinical evaluation. Reports on clinical allergies and adverse events are rarely published. This is due to lack of awareness of possible reactions to this metal, difficulties in detection methods or the metal is actually considered relatively safe.

What are the Diseases Caused by Metal Allergy?

Metal allergies can be seen as contact dermatitis where the allergen comes into contact, as well as common systemic allergic contact dermatitis. The most important problem seen in metal allergies is the rejection of implants and stents used in orthopedic, dental or cardiovascular diseases, leading to implant failure.

Allergic dermatitis and diseases caused by implants due to metal allergy

With regard to metal implants that are used extensively today, little is known about the relationship between metal release, metal allergy, and device failure in metal devices.

When the implants used in the body come into contact with body fluids, most of these metals rust and the metal ions released into the environment can bind to the proteins in the body and activate T cells, thus leading to the emergence of late-type allergic reactions on the immune system.

These late-type allergic reactions can sometimes manifest themselves as allergic contact dermatitis in the skin over the implants or may cause the implanted implant to fail.

The majority of intracoronary stents used in heart diseases are made of stainless steel containing nickel, chromium and molybdenum. Some studies have shown that coronary in-stent restenosis is associated with nickel allergy, especially in recurrent restenosis, nickel allergy has been shown to be a factor leading to vascular occlusion.

Gold allergy has also been associated with restenosis in patients with gold-plated stents, and therefore gold use has been largely abandoned.

Prostheses used by orthopedics are typically performed using cobalt-chromium-molybdenum containing materials. Studies showing a possible relationship between metal allergy, which has increased rapidly in recent years and implant failure, raise concerns about this issue. Publications on metal allergy in hip arthroplasty patients show that the prevalence of metal allergy is around 60% among patients with failed or poorly functioning implants.

It has been observed that allergic reactions are mainly against cobalt, chromium, nickel and molybdenum. Apart from complications such as implant dysfunction due to allergic reactions, it has been shown to cause serious clinical reactions such as aseptic lymphocytic vasculitic lesions or pseudotumors, sometimes in small numbers. In such cases, implants can be replaced with titanium-based endoprostheses. However, hypersensitivity reactions have also been described after placement of titanium implants, but titanium allergy is extremely rare.

In general, the allergic risk of titanium material is lower than that of other metal materials. However, pre-implant patients should be asked about a history of hypersensitivity reactions to metals, and patch testing should be recommended to patients who have experienced these reactions.

How to Diagnose Metal Allergy?

Is it possible to determine metal sensitivity responses clinically?

Approved methods used for diagnosis of metal allergy are in vitro blood tests including skin test (patch test) and lymphocyte transformation test (LTT).

Although commercial kits for patch testing exist for a variety of common metals, there are questions about the applicability of skin testing for diagnosis, as orthopedic implants have problems in generating immune responses.

One of the most important tests for metal allergy is the lymphocyte transformation test taken from the blood. This test is based on measuring the change in lymphocytes after the chemical substances that the patient is sensitive to contact with immune system cells in the blood. It can be used to verify patch tests in these tests on blood.

Other tests applied from blood can be used, lymphocyte migration inhibition test and lymphocyte immunostimulation assay (MELISA®), the newly developed form of LTT, besides all these, flow cytometric measurements can be used. However, despite all this, there is no single test to diagnose allergic contact dermatitis.

It is appropriate to perform these tests by allergists and, if necessary, to be confirmed by blood tests in doubtful cases.

How to Treat Metal Allergy?

It is seen that metal allergies can be encountered with many different clinics. It is important to investigate metal allergies, especially in patients with dermatitis complaints. Since metal allergies can lead to failure of prosthesis and implants, it is appropriate to diagnose patients with complaints before such procedures, prosthesis and implants should be selected from non-allergic materials.

Since the allergens and reactions that cause Metal Allergies can be very different from person to person, the treatment of metal hypersensitivity should be done individually according to the allergens the patient has contact.

The basic treatment method in metal allergies can be solved by not using the substance that causes skin hypersensitivity. If dermatitis is prominent in the reaction that occurs in metal allergy, corticosteroid creams and ointments may also be recommended to reduce local inflammation. He or she may also prescribe oral antihistamines to reduce an allergic reaction.

Oral corticosteroids can also be used if reactions are more frequent in metal allergy, but prolonged use may cause side effects.

Systemic reactions may be more difficult to treat. Because it is usually caused by implants. It may be necessary to remove the implant, sometimes using a non-metal head implant. However, if allergies are caused by an artificial knee or hip prosthesis, it is rarely replaced with a non-metallic option, although replacement is difficult. For these conditions, treatment usually can be given topical and oral medications to reduce the allergic reaction. If the reactions cannot be stopped in patients with systemic complaints, removal is absolutely necessary.

If there is a systemic nickel allergy due to nickel, desensitization treatments with nickel are applied. Although successful results were obtained with this treatment, a complete procedure could not be established.

Because systemic metal allergies are difficult to treat, doctors sometimes recommend performing a hypersensitivity test before selecting an implant. It is extremely beneficial for the patient to decide on the implant or prosthesis to be selected after the tests.

As a result

Metal allergy is a late type allergic reaction that the immune system gives to chemicals such as metals. In the 20th century, industrialization and modern life led to an extreme skin sensitivity to metals and thus an increase in metal allergy.

Nickel allergy, which we encounter most often when metal allergy is mentioned today, is mostly explained by exposure to nickel-containing consumer products.

It is estimated that metal allergy is high in the general population, 17% of women and 3% of men have nickel allergies.

Although titanium allergy is not generally known, it has reported that approximately 4% of all patients will be allergic.

In general, the allergic risk of titanium material is lower than that of other metal materials. However, pre-implant patients should be asked about a history of hypersensitivity reactions to metals, and patch testing should be recommended to patients who have experienced these reactions.

Metal allergies can be seen as contact dermatitis where the allergen comes into contact, as well as common systemic allergic contact dermatitis. The most important problem seen in metal allergies is the rejection of implants and stents used in orthopedic, dental or cardiovascular diseases, leading to implant failure.

Approved methods used for diagnosis of metal allergy are in vitro blood tests including skin test (patch test) and lymphocyte transformation test (LTT).

After the metal that causes metal allergies is detected, the patient must be removed from the metal causing the allergic reaction. Therefore, it will be beneficial for patients with metal allergies to be seen by allergists before prosthesis and implant, and to choose the most suitable prosthesis or implant after the tests are done and allergy is determined.