Euro coins 'trigger allergy'

The one and two Euro coins were studied

High nickel levels in some euro coins can cause red hands and painful itching, researchers warn.

Researchers from the University of Zurich say the design of the one and two euro coins - an external ring of metal surrounding an inner "pill" of a different colour - lead to the release of high levels of the metal.

They say the yellow and white alloys contain different amounts of nickel, copper and zinc, which encourage corrosion as metal ions flow from one alloy to the other when they are exposed to sweat for long periods.

It is only through continuous handling and through sweating that the nickel leeches into the skin and causes this reaction

Dr Clive Grattan, Norfolk and Norwich University Hospital

They could contain between 240 and 320 times the quantity of nickel allowed under the European Union Nickel Directive, according to the scientists.

They say this explains why some people suffer bad skin reactions to the euro coins, but not others such as the Swiss franc which have similar levels of nickel.

Allergic reaction

Seven patients who were sensitive to nickel had coins taped to their skins for 72 hours. All showed positive results when they were tested for allergic reactions.

A study published last November showed nickel levels in euros were high enough to trigger symptoms of eczema on the hands of people with allergies if they held the coins for five minutes.

And in January, a Barcelona hospital reported 20 patients had sought treatment for painful itching and red hands caused by handling the coins.

Constant handling

Dr Clive Grattan, a consultant dermatologist at the Norfolk and Norwich University Hospital welcomed the study.

"It is an interesting development and it could have important clinical implications."

But speaking to BBC News Online he added: "It is only through continuous handling and through sweating that the nickel leeches into the skin and causes this reaction."

The research is published in the journal Nature.