They put salt on the skin and then an ice cube to cause a ‘burn’ sensation, and try to endure the pain for longer.
Participants record themselves challenging themselves, to upload the resulting material to YouTube.
The mixture of ice, water and salt creates an eutectic cold mixture that can get as cold as -28 degrees Celsius and cause serious second and third degree injuries. Lesions are similar to those of freezing.
Discussing potentially dangerous, a spokesman for St John Ambulance, said: ‘Of course, we do not approve of this dangerous activity which is anything but a ‘challenge’.
‘If someone has suffered a burn, make sure they are treated immediately by cooling the affected area as quickly as possible.’
‘If the burn is on the face, hands, feet, or larger than the person’s hand size, it is likely to be a more serious burn and you should seek additional medical advice.’
The NSPCC has issued a warning about insanity. They said: ‘It is important that schools keep a close watch on all emerging trends and welcome the police warning by the chiefs of study.’
The rise of social media has contributed to increased peer pressure among children and this ‘madness’ is another clear example of risk.