Nickel allergy

Nickel allergy is one of the most common causes of contact allergic dermatitis. In affected individuals, dermatitis (eczema) develops in places where nickel-containing metal is touching the skin. The most common sites are the earlobes (from earrings), the wrists (from a watch strap) and the lower abdomen (from a jeans stud); the affected areas become intensely itchy and may become red and blistered (acute dermatitis) or dry, thickened and pigmented (chronic dermatitis).

Who is affected by nickel allergy?

Contact allergic dermatitis to nickel may develop at any age. Once this nickel allergy has occurred, it persists for many years, often life-long.

Nickel allergy is more common in women, probably because they are more likely to have pierced ears than men, although this is changing. The degree of allergy varies. Some people develop dermatitis (also called eczema) from even brief contact with nickel-containing items, while others break out only after many years of skin contact with nickel.

Can it affect areas that are not in contact with metal?

Some people develop intermittent or persistent eczema on their hands and feet. It is usually a blistering type of eczema, known as pompholyx. Sometimes it is due to contact with metal items containing nickel, but often there is no obvious reason for it.

It has been suggested that in some, dyshidrotic hand dermatitis is due to nickel in the diet. Unfortunately it is not possible to avoid ingesting nickel as it is present in most foodstuffs. A low-nickel diet is only rarely helpful.

Nickel dermatitis

Due to jeans stud	Due to rings	Due to watch strap
Spectacle frame	Pompholyx in nickel allergic patient	Strongly positive patch test to nickel sulphate

Diagnosis

Nickel allergy is diagnosed by the clinical history and by special allergy tests, patch tests.

Subjects are specifically tested to nickel sulphate-hexahydrate. The chemical formula for this is NiO₄S.6H₂O.

Treatment

• Compresses Dry up blisters with diluted vinegar compresses.
• Topical steroids Apply topical steroid to the dermatitis as directed.
• Antibiotics Antibiotic creams or pills may be necessary for secondary infection. Usually a penicillin antibiotic such as flucloxacillin is chosen.
• Emollients Apply soothing emollient creams frequently to relieve itch and dry skin.

Unfortunately, desensitization with injections or pills is not possible.

Avoid nickel

It is essential to avoid contact with nickel-containing metals.

Test your metal items

Test your metal items to see if they contain nickel. Obtain a nickel-testing kit from your dermatologist or pharmacist. The kit consists of two small bottles of clear fluid; one contains dimethylglyoxime and the other ammonium hydroxide. When mixed together in the presence of nickel, a pink colour results.

Apply a drop from each bottle on to the metal item to be tested - first try it on a 10 cent coin. Use a cotton bud to rub gently - observe the colour on the bud. If it remains clear, the item has no free nickel and will not cause dermatitis. If it is pink it contains nickel and may cause problems if the metal touches your skin. The chemicals will not harm your jewellery.

Jewellery

Necklaces, necklace-clips, earrings, bracelets, watch-straps and rings may contain nickel. "Hypoallergenic", solid gold (12 carat or more) and silver jewellery should be safe. Nine carat gold and white gold both contain nickel. Plastic covers for earring studs can be obtained. Coating the stud with nail varnish is not recommended.

Clothing

Metal zips, bra hooks, suspender clips, hair-pins, buttons, studs, spectacle frames etc. are likely to contain nickel. Use substitutes made of plastic, coated or painted metal or some other material.

Personal articles

Consider mobile phones, lipstick holders, powder compacts, handbag catches, cigarette lighters, razors, keys, key rings, pocket knives, pens as potential causes of dermatitis.

Metal items in the home

Cupboard handles, kitchen utensils, cutlery, toaster, metal teapots, scissors, needles, pins, thimble, vacuum cleaners, torches, bath plugs... may all contain nickel. Choose tools with plastic handles. Stainless steel does not usually cause dermatitis unless it is nickel-plated.

Money

Silver coins are composed of cupro-nickel. Cashiers with nickel allergy may develop hand dermatitis from this source. Wear gloves to handle money or pay with a credit card or cheque.

Metal at work

Nickel dermatitis may be aggravated by contact with paper clips, typewriter keys, instruments, metal fragments from a lathe or chain saw.

Low nickel diet

• Foods allowed
  
  Meat, poultry, fish, eggs, milk, yogurt, cheese, quark, butter, margarine
  Cereals, bread, flour, rice, pasta Small servings of wholemeal flour, wholegrain
  cereals, wheatbran and wheatgerm
  Most vegetables
  Small servings of beetroot, cabbage, cauliflower, leeks , parsnips, potatoes, spinach
  Fruit, raw & stewed
  Tea, coffee, soft drinks, cordials, beer, wine
  
• Foods to avoid
  
  Canned spaghetti & baked beans
  Green beans, broccoli, peas including split peas, canned vegetables
  Canned fruit, dried fruit, nuts Cocoa, drinking chocolate, chocolate