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Frequently Asked Questions (FAQs)

Why is metal allergy not widely known?

Metal allergy is recognised by health professionals, but the focus is on contact dermatitis, that is when skin is contact with metal items such as jewellery. A rash, blister or other change in the skin will appear at the contact point.
 

What is often neglected and not well-known, is systemic metal allergy, when not only the skin but other organs are effected, and not always at the point of contact with the metal. This reaction can happen as all metal alloys corrode, releasing metal ions, which will bind to proteins and enzymes in the body. In genetically predisposed people, this may stimulate the immune system to respond, leading to a variety of often unspecific symptoms, such as fatigue. The symptoms will persist until the exposure is stopped.   
 
Currently, the golden standard for testing of allergy to metals is patch testing. This is a skin test where metals salts are placed on the skin of the back under occlusion. The test is not objective and may cause discomfort for patients. Also, the test often does not work for some metals like titanium as, titanium dioxide, a salt of titanium used for patch testing, does not penetrate the skin under the conditions of patch test, and the results are almost always negative.

What are the symptoms of metal allergy? 

The symptoms most often observed after chronic, low dose metal exposure, for example after implantation of orthopedic implants or the insertion of dental crowns and fillings, are varied, and not every patient suffers from the same symptoms. In addition to localised symptoms such as ulcers or sores adjacent to implants on the mucosa in the mouth or rashes and/or urticaria on the skin, there might be distant systemic symptoms. They are similar to the symptoms described after the exposure to any other allergens in sensitised individuals. Symptoms arise because stimulated lymphocyte produce cytokines, which in turn affect the HPA-axis. The result is multiple non-specific symptoms such as profound fatigue, pain, cognitive dysfunction, headaches, sleep problems etc.

What should be considered before MELISA testing? 

Ideally, patients should contact their dentist or surgeon to find out the exact composition of the fillings, crowns, wires, pin and/or implants.


Some patients will not have any metal restorations or implants but will be exposed to metals in other ways. Our pre-test questionnaire will show which metals a patient is likely to be exposed to.

Sources of common metal exposure are:
•    Dental restorations: fillings, crowns, pins, root-fillings, implants. Amalgam/silver fillings contain mercury, silver, tin, copper and zinc. Crowns can contain gold, silver, palladium, copper, chromium, indium, gallium, iridium, nickel and more. Implants are often made of titanium, aluminium and vanadium.
•    Orthopedic and body implants such as hip replacements, screws, nails, clips may be made from titanium or stainless steel.
•    Common implant alloys are:
•    Stainless steel: Nickel, chromium, manganese, molybdenum
•    Cobalt-chromium molybdenum steel: Chromium, molybdenum, nickel, iron, manganese, tungsten, aluminum, titanium, cobalt
•    Vitallium: Cobalt, chromium, manganese, molybdenum
•    Titanium: Aluminum, vanadium, nickel (trace)
•    Nitinol: Titanium, nickel
•    Oxinium: Zirconium (oxidized)
•    Smoking: both active and passive, cigarette smoke contains mercury, nickel, cadmium, manganese
•    Vaccines: may contain thimerosal, a mercury-based preservative, and aluminum as an adjuvant
•    Medication: antacids contain aluminium and pills may have titanium dioxide (E171) or other metal oxides in their coatings. Antiseptic preparations used to contain mercury and still do in some countries. Barium is found in x-ray fluids.
•    Piercings and jewelry:
•    Costume jewelry may contain a lot of different metals, most notably nickel, which often cause skin rashes in sensitive people. Lead may also be present.
•    More expensive jewelry, such as yellow gold is made by mixing pure gold with copper and zinc; rose gold contains copper, and white gold is an alloy of gold and some white metals such as silver and palladium. Other metals used in jewelry are platinum, rhodium, tungsten and titanium. Titanium is often used for piercings and there are some rare cases of allergy to titanium alloy piercings.
•    Cosmetics: Titanium dioxide (TiO2) is widely used in cosmetics, present in many eye shadow, blusher, nail polish, lipstick, powder and sunscreen. Metal pigments are used to give colour and act as preservatives. The following metals may exist in costmetic products: lead, mercury, chromium, aluminium, arsenic, beryllium, nickel, thallium, cadmium and others.
•    Food from contaminated areas contain more metals than others, whether it's fish, meat, vegetables or fruit.
o    Fish can contain high amounts of methyl mercury, which accumulates up in the food chain so that large predatory fish contain more mercury than smaller fish.
o    Seafood may contain mercury, cadmium and arsenic.
o    Nickel is found in bananas, cocoa, oatmeal, green vegetables and a variety of other foods.
o    Vegetables from polluted areas may contain cadmium, palladium, lead etc.
o    Tinned food can contain tin and aluminium.
o    Wine can contain molybdenum, nickel and lead.
•    Occupational exposure: construction workers, miners, electricians, rubber/wood/paper/textile industry workers, dentists, hairdressers and painters are some occupations that will be have greater exposure to metals in their work than others.
•    Living close to a highway, airport, crematory and factory or in the same house as a dental clinic may lead to increased exposure to metals such as palladium, cadmium, lead and mercury.

How is MELISA testing provided? 

Licensed MELISA laboratories can be found in different parts of the world. Laboratories refer patients to clinics they work with or send out a test kit with all necessary materials and instructions. Blood is taken into citrate tubes, which are then sent the same day to a testing laboratory, arriving the next day or within 48 hours. Fasting is not required and the blood should not be refrigerated but kept in room temperature.

How long does it take to get the results back? 

About 14 days, from the time the sample is sent.

Why should steroids be avoided before the blood draw? 

Steroids and other immunosuppressive medication inhibit the white blood cells that are needed to perform the MELISA® test. If the white blood cells, lymphocytes, are inhibited the test will likely come back as a false negative. That means that no allergy was measured, even though the patient is actually allergic.

Ideally, all use of steroids should be suspended. This includes:

- Topical creams
- Inhalation sprays (such as are used by asthma patients)
- Oral preparations (pills or capsules)

Patients should always consult their doctor before suspending any ongoing medication.

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