The application of extreme cold to minor burn injuries is now considered to be so effective that it has become almost a knee jerk response and as such is undoubtedly the treatment of choice. There are three possible explanations for its beneficial action:-
removing excess heat to prevent further injury,
modulating damaging effects of the immune response,
mounting the placebo effect.
Although all three mechanisms may make a significant contribution, the evidence that tempering the immune response is the major factor is supported by the remarkable effect of cold shock on bruising injuries commonplace in the DIY world. The proviso must include the probability that part of the placebo effect is also to modulate the action of the immune system and that it is not the application of cold that minimises the maturation of the bruise, but the belief in its efficacy.