A Chinese girl has baffled medics after her skin turned into 'cow hide'.

Over the past few months, a small birthmark on Li Xiaoyuan's back has started to spread all over her torso, arms and face.

The hairy blue-grey growth now covers the majority of her skin.

Her mother, Li Jiang, said: "The poor girl - it breaks our hearts to see her suffer like this."

Surgeon Dr Lou Zhongguan from the Zhaoqing City Dermatological Hospital believes Li might be suffering from a rare hereditary disease which causes normal body moles to go out of control.