People who use their mobile phones for long periods of time could develop an allergic skin rash, health experts have warned.

The British Association of Dermatologists (BAD) warned that people may develop rashes on their cheeks or ear due to the nickel contained in some mobile phones.

The issue came to light after several reports of patients with unexplained skin disorders.

Experts found that the reaction was caused by nickel in the casing or on the buttons of some mobile phones.

The BAD said doctors and the public should be aware of the risk, with cases estimated to be on the rise. Many cases could be going unreported.

People with a known reaction to nickel — a metal also used in jewellery — are thought to be most at risk.

Reports of several cases have been published in medical journals including the Journal of Investigative Dermatology and the British Journal of Dermatology.

Dr Graham Lowe, from the British Association of Dermatologists, dubbed the condition "mobile phone dermatitis".

He said: "The allergy results from frequent skin contact with nickel-containing objects. Prolonged or repetitive contact with a nickel-containing phone is more likely to cause a skin reaction in those who are allergic.”