What Is Metal Allergy?

Overview

Metals are everywhere! We live together with them, we see them, we touch them every day. However, they are allergens. Allergens can cause allergies. Some of us seriously suffer from metal allergies due to genetics being sensitive to the metals. Some of us get a metal allergy after prolonged exposure to metals for a variety of reasons, for instance; wearing jewellery or working at manufacturing factories involving heavy metal ingredients. Treatments for certain metal allergies may still be a long way off, but there are obvious prevention and protection methods we can apply in our everyday lives.

What is a metal allergy?

Allergy is the case where our body shows an excessive response to the allergens. Those allergens are known as foreign substances in the body, which normally do not harm non-allergic people.¹ Allergic bodies cannot distinguish between safe and unsafe substances at some point and react to them at the same level.

Metal allergy is a condition related to environmental exposure to certain metals. This exposure can be either by touch, eating, or inhalation. After contact with the metal, the body gives different types of reactions that change for different people. This situation is called metal allergy.²

What are the common metal allergens?

Any type of metal can cause allergy, even if it is rare. Therefore, it is important to be careful and know your body well. We can list the highly common metals known to cause allergic reactions.³

• Nickel
• Chromium
• Cobalt
• Gold
• Palladium
• Titanium
• Arsenic
• Silver

What are the causes of metal allergy?

Some of us are genetically prone to metal allergy, whereas some of us without any genetic sensitivity can also develop metal allergy due to long exposure to certain metals. The biological reason for all of these is the errors in our immune system. Our immune system overreacts to the metals and shows many responses against them, which are observed as symptoms.

Where do we get metal exposure?

Different environments contain different types of metals. However, metals are extremely prevalent elements. It is very unlikely to spend a day without seeing or touching any metal.

Nickel is a highly common chemical element found in our everyday life. It is an end product of a combination of cobalt, palladium, iron, titanium, gold, and magnesium elements. Most jewellery is also made of nickel, and people assigned female at birth (AFAB) have been confirmed to have a risk four times higher of suffering from nickel allergy compared to people assigned male at birth (AMAB).³ However, the main source of nickel allergy is the food that we eat.

On the other hand, cobalt is a hard metal, and it has a connection with the nickel allergy. People who have cobalt allergy are very likely to have nickel allergy as well.  When nickel and cobalt allergy occurs at the same time, the effect is more severe. Food is a source of cobalt, too; however, mainly the workers from the hard metal industry develop a cobalt allergy during the manufacturing process after the exposure.³

Chromium is widely utilised for plating, leather tanning, pigmentation, dye production, metallurgy, and chemical industries.³ Moreover, it is also found in prostheses and other implants. The chromium allergy occurs either by ingestion of chromium or contact with chromium element-containing product. 

What are the symptoms of metal allergies?

Contact Dermatitis (CD) is observed as pruritus, erythema, vesicles, and scale. It is a skin disease that results from allergic inflammation (swelling).⁴ Metals are capable of causing CD; meanwhile, if they enter into our circulatory system, where the blood is carried around the body, they can cause systemic contact dermatitis (SCD).³

How to diagnose a metal allergy

The ultimate method for diagnosing metal allergy is carrying out patch tests (PTs).² The patch test is simply putting a patch with a pre-proposed allergen and placing it onto the patient's back. Then, the area is monitored for signs of swelling, redness, and itchy skin.¹ It is a common method for other types of allergies. Therefore, you can be familiar with this method.

However, as false positive and false negative results can be difficult to distinguish, a professional should carry out these tests.² The time interval for observing a positive result from a patch test can be between 7 and 45 days. This depends on the age of the individual and the type of the allergens. Hence, the applicant should not be quick to come to a conclusion about the result of the test. Also, metal allergens display positive results on longer days by using the PTs method.

The in vitro lymphocyte proliferation test (LPT) is another test carried out to diagnose metal allergies; however, these are preferred when the metal allergy does not have skin-related contact. In this test, the evaluation of the numbers of different types of immune cells gives us an indication of specific metal allergy.2 These different types of immune cells can be assumed as biomarkers, which are the biological predictors of an underlying health condition, metal allergy in that case.

How to treat a metal allergy

The most common way of treatment is using antihistamines and medicines for the prevention of inflammation.² However, there are no FDA-approved drugs used directly for metal allergy treatment.⁵ Therefore, the typical creams, tablets, and needles applied for allergies are used for the treatment of metal allergies, and in the case of implants, the situation can be as severe as removing the implant for a definite solution. Currently, prevention methods are the foremost option for the mental allergy.

How to prevent metal allergy

There are assorted approaches to prevent metal allergy, such as strengthening the skin barrier, protecting the skin barrier, pre-determination of the allergy before the application of metals onto the body, altering the diet, and warning labels for the exposure of metals for the companies and industries, as well as avoidance of metal allergens in everyday products in your daily life.⁵

We can subdivide the prevention methods mentioned above into titles and clarify the points further:

1. Enhancing and protection of the skin barrier

Emollients, which are moisturising creams with protective barriers, can be applied onto the skin before touching a metal allergen. 

2. Determination of the allergy

Patch-testing should be applied in suspicious situations before the application of any implants, operation materials or prosthetics onto patients. 

3. Altering the diet

Some foods such as cereals contain high levels of nickel.⁵ The fish, vegetables and dry fruits also contain heavy metals. Therefore, dietary adjustments are needed for the prevention of metal allergies.  

4. Awareness of the risks at the companies and industries

Companies and industries should be well aware of their metal-exposed working environments. They should strictly take precautionary measures and give relevant instructions and education to their workers. Also, they should apply pre-testing rules for metal allergy before starting the contract with the employees. Most of the workers are unaware of the risks involved within their work environment.

5. Daily Exposed Metals

Hypoallergenic jewellery, non-metal toys, and non-metal buttons containing clothes can be given as examples of taking precautions in everyday life routines. Moreover, industries should take into consideration the people with metal allergies for the production of technological devices, which are the causes of persistent exposure.

Placing metals into our body

The replacement of bodily parts with a metal component is known as an implant. Those implants stay inside the body forever. Unfortunately, the metal allergy can appear years later and cause severe pain, swelling as well as an urgent requirement for an operation to remove the implant. Those implants can be breast, cardiac, dental, vascular, or orthopaedic. In that case, it is highly life-threatening to monitor the patients for a long period of time before the implant. 

In a study, they have shown that, after monitoring the patients for metal allergy over a 3-year period, they have changed the metal knee arthroplasty with a hypoallergenic material.⁶ This resulted in a reduction of pain, increased ability for walking, and many other types of motion. 

Summary

Metal allergy is a very common issue due to the high presence of metal allergens in our daily lives. At the same time, the possibility of preventing metal allergy is very likely. The only important point is awareness. The awareness starts from the self, and it involves awareness of the employers and health professionals as the great responsibility. You should closely observe your body and avoid metal contact in your daily life. Moreover, there should be detailed guidelines for industrial jobs involving metal allergy warnings and explanations. On the other hand, before any implant and operation, metal allergy tests should be carried out to prevent life-threatening outcomes. Finally, you should avoid diets involving intensely consuming certain types of food before getting professional guidance from food professionals to prevent food-related metal poisoning/allergies.