Diagnosis of a nickel allergy
The suspicion of a nickel allergy is usually determined by a doctor on the basis of the skin symptoms and the patient’s medical history. The doctor will ask the patient in detail when and where the rash occurred and whether this can be linked to certain items of clothing or jewelry, for example. An allergy test is then performed to confirm the diagnosis of nickel allergy.
In this case, an epicutaneous test (also called patch test) is used, in which the doctor applies patches treated with test substances to the patient’s upper arms or back. Normally, other allergens such as fragrances or other metals are tested in addition to nickel. These patches must remain stuck for at least 48 hours and must not come into contact with water during this time.
After this period, the doctor removes the patches and inspects the skin underneath. If the skin shows a reaction to the nickel patch, an allergy is present.If the allergy is confirmed by this, it is recommended to note this in an allergy passport. A blood test, which is also possible, plays only a minor role in the diagnosis.
In order to test or exclude an allergy to nickel, skin contact with nickel is usually induced over a longer period of time. In concrete terms, this means that several platelets containing the allergy-causing nickel ion are stuck onto the body, i.e. usually onto the back. Scribing the skin, as is often done in allergy tests (“prick test“), is rather unusual here.
The platelets usually remain on the skin for at least one day. If a skin reaction occurs during this time, a nickel allergy can be assumed. If there is no redness or eczema, an allergy to nickel is very unlikely.
In addition, the doctor sometimes prescribes a low-nickel diet in order to check a possible connection between skin reactions and nickel intake through food. This diet is then maintained for a few days and may suggest a nickel allergy if the symptoms improve. However, people with nickel allergies can sometimes tolerate foods containing nickel.
