Mark V. Dahl, MD reviewing Garibyan L et al. J Invest Dermatol 2015 Nov.

Skin cooling induced month-long diminution of mechanical and thermal pain sensation but did not affect perception of itch.

Cryolipolysis uses skin cooling to reduce fat. Hypoesthesia over the treated area is a usual side effect. Cooling causes crystallization of cytoplasmic lipids, selectively injuring fat cells, and apparently nerve cells as well. Perhaps cryolipolysis could be used to treat chronic cutaneous pain or itch?

To study this hypothesis, investigators prospectively evaluated nociception by quantitative sensory testing to a range of stimuli in 11 healthy subjects with visible adiposity of the thighs. Skin on one leg was cooled with cold metal plates for 60 minutes, and the other leg served as a control. Hyposensitivity to mechanical pain was observed at each time point for 56 days. The mechanical pain threshold was raised compared to baseline and control sites. Control sites saw no change. The cold pain threshold also increased. This effect began 48 to 72 hours after treatment and persisted for at least 35 days. The heat pain threshold was less affected. Thresholds for detection of vibration, warmth, and coolness significantly increased after cryolipolysis treatment. Response to itch provocation was evaluated by testing after histamine iontophoresis. The peak itch and general intensity of itch seemed unaffected. Skin biopsy specimens at baseline and 21 and 56 days after treatment showed reduced densities of dermal myelinated nerves (P<0.001). Unmyelinated nerves were also reduced, but not as much.

Citation(s):

Garibyan L et al. Transient alterations of cutaneous sensory nerve function by noninvasive cryolipolysis. J Invest Dermatol 2015 Nov; 135:2623.

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