The ChillTip handpiece must be in firm contact with the skin. A single pulse should be placed at test sites within or near the treatment area. If epidermal damage is present (blistering, abla- tion, graying or whitening of the epidermis, or a positive Nikolski sign) the fluence should be lowered by 5 to 10 J/cm2 . Several pulses should then be placed next to one another while looking for the epidermal response. An effective fluence is one where the hair carbonizes, followed by very selective follicular swelling and redness. .
