Fears are being raised that 5p and 10p coins being introduced into circulation could cause skin problems.
The coins are made from steel but plated in nickel, replacing the current cupro-nickel version which contains 75% copper and 25% nickel.
Dermatologists told the British Medical Journal the move could cause problems for people who have nickel allergies, including some people with eczema.
But the Royal Mint said the change would not have an adverse impact.
The new coins, which come into circulation in the next few months, are being introduced because of the rising cost of copper.