What is nickel allergy?
Allergy to nickel is one of the most common forms of contact allergy. People with a nickel allergy develop red, itchy skin lesions after (prolonged) skin contact with nickel. Nickel is a non-precious metal that is very widely used in all kinds of metal objects.
Who gets it?
Nickel allergy occurs more in women than in men and can develop at any age. Once a nickel allergy has developed it persists for many years to lifelong.
How does it develop?
After (usually prolonged) skin contact with nickel, the body can become “sensitised” to nickel: white blood cells are programmed to react with skin inflammation on contact with nickel. Usually each subsequent contact must be fairly prolonged before the reaction occurs — briefly grasping a nickel doorknob usually causes no reaction, but wearing nickel jewellery on the skin does. In people with a very strong nickel allergy, short contacts can also cause complaints.
How is nickel allergy established?
The dermatologist can establish a nickel allergy by means of allergy tests on the skin (patch tests). Usually other possible allergens are tested at the same time. The substances are applied to the skin with special patches for 48 hours; the patches are then removed and it is assessed whether there is a reaction on the skin, which is checked again 24 hours after removal. When a red spot has arisen at the site of the tested substance, there is a contact allergy.
What does it look like?
An allergy to jewellery, press studs or bra fastenings is usually quickly recognised, because these objects often leave an “imprint” of itchy eczema on the skin, often with a more extensive red edge around it. In people who come into contact with nickel occupationally, an extensive hand eczema can also arise. People with a nickel allergy very often also have long-lasting hand (and sometimes foot) eczema, even without obvious prolonged direct nickel-on-skin contact; usually there are small, clear-fluid-filled blisters on the palms and sides of the fingers that dry up into hard scales and cracks. This resembles dyshidrotic hand eczema.
How do I prevent eczema from nickel?
Once a nickel allergy has been established, it is wise to avoid contact with nickel objects — easier said than done, because nickel is worked into so many everyday items. Avoiding jewellery is achievable; it is useful to know that silver and gold jewellery often also contain traces of nickel, and generally, the higher the quality of the jewellery, the smaller the chance of nickel. The more intensive the contact with the skin, the greater the chance of problems (examples of intensive contact are piercings, ear studs and watches). Think too of less obvious nickel contacts such as trouser buttons (a shirt between button and skin gives insufficient protection) or a bunch of keys in a trouser pocket.
How is the eczema treated?
Usually it is enough to remove the source of the nickel. The eczema and itch can disappear faster when a corticosteroid ointment is applied for a few days to the affected patches. When there is a severe eczema with blistering (usually on the hands), the doctor can also prescribe ointments to dry the blisters first.
Nickel in the diet
Severe eczema on the hands (and/or feet) is fairly often seen in patients with nickel allergy, and some researchers link this to nickel in the diet, though firm evidence is lacking. It is impossible to remove nickel entirely from the diet because it is present in almost all foods; some foods contain relatively a lot (such as canned food and chocolate). Following a low-nickel diet only rarely improves the eczema.
When to see a doctor
See your GP or a dermatologist if you have recurring itchy eczema where metal touches the skin (jewellery, watch, buttons), or persistent hand eczema of unclear cause, so patch testing can confirm a nickel allergy. Treatment plus avoiding the source usually controls it well.