Allergy risk of body piercing

Earrings were scrutinised by the researchers

Body piercing has been blamed for a steep rise in allergies to nickel across the Western world.

Nickel is already the most common cause of contact allergy in several European countries.

Exposure to the metal can cause lifelong sensitivity. Sufferers find many belt buckles, wristwatches, glass frames and jewellery impossible to wear.

A nickel allergy can occur at any age, and typically appears a few days after first contact as eczema, which appears as an itchy, dry/crusty, and red/pigmented skin rash with watery blisters.

The affected area is usually restricted to the site of contact, although it could also be found on other parts of the body. Once a nickel allergy has developed, it is usually a chronic condition and often life-long.

Skin allergies triggered by nickel earrings and studs can lead to further health problems.

Once sensitised by exposure to nickel, sufferers are more likely to develop allergies to other substances.

European guidelines

Navel piercing can lead to allergy problems

European Union guidelines say that earrings are supposed to contain less than 0.05% nickel by weight and should not release more than 0.5 micrograms of the metal per square centimetre of their surface area per week.

But Finnish scientists from the Helsinki City Centre for the Environment warn that many earrings exceed these limits - including some billed as gold or surgical steel.

The researchers used several methods to test the nickel content of 66 ear studs and earring backs imported into Finland from Germany, Sweden, Britain and the US - all of which were said to contain amounts of nickel well below the EU limits.

The first test they carried out was one used by most government authorities, which involves swabbing an earring with a solution containing ammonia and dimethylglyocime.

This should produce a red colour if the metal contains any nickel. None of the earrings tested positive.

However, when the researchers performed a variation of this test, in which the earrings were exposed to artificial sweat for up to a week, nine of the 66 pieces of jewellery tested positive.

And when they used a different method, atomic absorption spectrometry, 25 were found to exceed EU limits.

Researcher Antti Pönkä, writing in New Scientist magazine, says the swab test for nickel has been giving misleading results. "It's useless," he says.

He adds that subsequent studies, yet to be published, have shown that other types of jewellery, intended for pierced tongues, cheeks and genitals, are even worse. Eleven of 12 items tested exceeded EU safety limits.

The EU directive was drawn up in 1994 but will not come into force in all the member states until agreed tests are officially published.

Adhering to nickel content and emissions limits will not always be easy, however.

Stephen Carter, who works for LGC, an independent laboratory in south London, said: "There's such a wide range of jewellery - it's quite a difficult problem for importers to ensure they meet those requirements.

"The best way to solve it is for people not to use nickel."