Nickel allergy

Reddening of the skin and itching can be symptoms of a nickel allergy. Nickel is often found in jewelry, belt buckles or in glasses frames. Nickel allergy is one of the most common allergies in Germany. More about causes, diagnosis and therapy

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Nickel in jewelry can cause contact allergies

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Nickel allergy - in short

A nickel allergy usually manifests itself in an itchy rash that occurs on the relevant parts of the body after contact with nickel-containing materials. In contrast to the immediate type I allergies (including, for example, pollen, insect venom and most food allergies), the reaction is delayed in this so-called late type (type IV).

In some cases, diet can affect symptoms. A doctor made the diagnosis based on the symptoms and with the help of an allergy test (patch test). If it is certain that there is a nickel allergy, contact with this material should be avoided as far as possible. Anti-inflammatory agents, for example in ointments or creams, and in severe cases tablets that suppress the immune response relieve the symptoms. In consultation with your doctor, a diet that is low in nickel may be helpful.

What is a nickel allergy?

In the case of a nickel allergy, the body's own defense system (immune system) reacts to nickel - after contact with objects containing nickel. The body's defenses "mistakenly" classify nickel as a dangerous intruder that needs to be fought. The so-called type IV sensitization to nickel is the most common allergy to contact allergens in Germany. It occurs within the population with a frequency of around 15 percent, whereby women are more likely to be affected than men. However, nickel allergies have become rarer in this country since a regulation was implemented in 1994 that is intended to reduce nickel exposure. Objects such as jewelry are only allowed to release a certain amount of nickel, namely no more than 0.5 µg nickel per square centimeter per week.

As already mentioned, the nickel allergy is one of the so-called contact allergies: When coming into contact with objects containing nickel, the slightly acidic sweat of the skin can dissolve nickel ions from a metal. These then penetrate the horny layer of the skin, the physical skin barrier. In people with a corresponding predisposition, the immune system (the so-called body's own defense) reacts to these nickel ions. A nickel allergy is preceded by a phase of so-called sensitization, in which the immune cells learn to recognize nickel as harmful and to react to it. When the skin comes into contact with the skin again, there is a defensive reaction with the typical local, and in very rare cases, generalized skin rash.

Nickel is a metal that is vital for the body as a trace element, as it is necessary for the function of certain enzymes. However, nickel is harmful in larger quantities. Nickel absorbed through food gets into the blood, is bound to certain proteins, partly stored and partly excreted in the urine. Nickel irritates the skin of almost everyone when it is applied in high concentrations. In the case of a nickel allergy, however, a small amount of nickel is enough to trigger an eczema reaction (inflammation) on the skin.

How does a nickel allergy come about?

Nickel ions are actually too small to be recognized by the immune cells in the skin. But nickel has the property of forming a bond with certain proteins. In this way, the substance can activate special defense cells in the skin. They release messenger substances that cause an inflammatory reaction (an allergic eczema) on the very areas of the skin that came into contact with nickel. In principle, even small amounts of nickel can be enough to cause allergic eczema. Fortunately, the skin changes are usually only mild to moderate and are associated with mild itching. Nickel ions dissolve in sweat and penetrate the skin. Pre-existing skin damage increases the risk of developing a nickel allergy.

Where is nickel found?

Nickel occurs as a chemical element in alloys or can be found as a charged particle (cation) in chemical compounds (salts, complexes). Nickel is widespread in the environment and is largely processed industrially. For example, it can be found in costume jewelry, glasses frames, coins, buttons, fasteners, paints, prostheses, batteries and various objects and materials. Ordinances regulate what amounts of nickel, for example from piercings or costume jewelery, may pass onto the skin. Occupational skin contact with nickel-releasing surfaces occurs, for example, in electroplating or when assembling nickel-plated parts.

Nickel is also found in food, plants and cigarettes. Larger amounts can be found in cocoa, black tea, coffee, mussels, nuts, legumes and whole grains, for example.

Symptoms

Nickel allergies are among the contact allergies. Only a few hours to days after contact with nickel-releasing objects (exposure) do the relevant areas of the skin begin to redden, ooze or itch. Small nodules (papules) and vesicles typically form. This allergic contact eczema generally only develops in the areas that have been exposed to the nickel. For example, the skin near the belly button is inflamed if a belt buckle there triggered the allergy. In addition, skin changes can also occur on the face, for example, due to spreading with the hands or contamination of applied cosmetics. Later on, the skin changes will heal on their own, provided the skin does not come into further contact with nickel.

Permanent skin changes, chronic allergic contact eczema, occur only with frequent or constant contact with nickel. The skin flakes off, tears and is inflamed in places and thickened. In some areas it becomes horny and rough.

If larger amounts of nickel are ingested with food, skin eczema can worsen in individual cases with a nickel allergy.

If dentures are the trigger for a nickel allergy, there are changes in the mucous membrane in the mouth.

Even if a nickel allergy is usually associated with severe itching, the inflamed areas should not be scratched. Scratching delays healing and makes infections more likely.

A patch test can be used to determine whether there is nickel sensitization

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Diagnosis: The patch test confirms the suspicion

The first point of contact is often the family doctor. He can refer to a specialist in skin diseases (dermatologist). Ideally, this has the additional designation of allergology.

In order to determine a nickel allergy, the doctor first asks about the medical history. He would like to know how long the skin changes have existed, where and on what occasions they appear. You may then already notice that, for example, certain pieces of jewelry could be the trigger for the complaints. The doctor then examines the affected skin areas.

The proof of nickel sensitization is then possible with the so-called patch test: Here, nickel sulfate is stuck to the skin of the back with a plaster - together with other substances that can trigger a contact allergy (such as metal salts, fragrances, preservatives). If there is hypersensitivity to nickel, the skin reacts after a few hours at the exact point where nickel sulphate was stuck on. After 24 or 48 hours, the doctor takes the patch off and examines the skin changes at the test site. Finally, the patch test is usually evaluated after three to seven days.