New nickel 5p and 10p coins should be investigated over the possibility they may cause disease, a group of skin experts has said.
The dermatologists expressed concern that the potential cost of skin disease related to nickel exposure has not been examined.
They have called for the "poorly informed" Royal Mint to consider the financial implications of treating patients, and the cost to the Treasury if those people are unable to work.
New 5p and 10p coins are made of nickel-plated steel and are gradually being phased into circulation.
The skin experts said the Swedish authorities concluded that this type of coin posed unacceptable health risks.
The letter, written by Danielle Greenblatt and Ian White of St John's Institute of Dermatology, and David Gawkrodger of the Royal Hallamshire Hospital in Sheffield, asks the Royal Mint whether a risk assessment has been completed to determine the effect of the coins on people who suffer allergic reactions to nickel.
They also asked what amount of nickel is released from the surface of the new coins.
Government chief scientist Sir John Beddington should give his opinion on the matter, they concluded.