Women are at higher risk of developing mobile phone dermatitis since they are more likely to have been sensitized to metal after an allergic reaction to nickel-coated jewelry. (AP Photo/Bob Child)

People who use their cellphones for long periods may develop a rash on their ears or cheeks, British dermatologists warned.

An unidentified rash or itchy skin, known as "mobile phone dermatitis," may occur if people develop an allergic reaction to the nickel in cellphone handsets, the British Association of Dermatologists said in its advisory to doctors on Thursday.

"In mobile phone dermatitis, the rash would typically occur on the cheek or ear, depending on where the metal part of the phone comes into contact with the skin. In theory it could even occur on the fingers if you spend a lot of time texting on metal menu buttons," said Dr. Graham Lowe, from the British Association of Dermatologists.

"It is worth doctors bearing this condition in mind if they see a patient with a rash on the cheek or ear that cannot otherwise be explained," he added in a statement.

Women are at higher risk of developing mobile phone dermatitis since they are more likely to have been sensitized to metal after an allergic reaction to nickel-coated jewelry, according to the association.

Other nickel-coated objects such as a belt buckle may cause the reaction.

Anyone who develops a facial rash that might be attributed to prolonged use of a cellphone should seek advice from a doctor, the association advised.

Fashionable designs more likely to contain nickel

In January, Lionel Bercovitch of Brown University in Providence, R.I., and his colleagues tested 22 popular handsets from eight different manufacturers and found nickel in 10 of the devices.

"Given the widespread use of cellphones, the presence of metal in the exterior casing of these phones and the high prevalence of nickel sensitization in the population, it is not surprising that cellphones can cause allergic contact dermatitis," Bercovitch said.

Menu buttons, decorative logos on headsets and the metallic frames around a phone's screen were the most common places where nickel was found.

"Those with the more fashionable designs often have metallic accents and are more likely to contain free nickel in their casings," Bercovitch added.