Page 253 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
That requires an appropriate level of fluence. But, some of this fluence is stolen by the epidermal melanin, which causes pain. Pre-cooling the skin, and the thermal pain nerves, reduces the likelihood of pain.
Pre-cooling the skin not only reduces the chances of pain, but it also reduces the likelihood of blistering and pigmentary changes. It makes the whole experience much more comfortable which means your patients/clients are more likely to return, and more likely to tell their friends and family too.
Post-cooling is also important. As mentioned previously, less than 10% of the fluence we fire into the skin is actually ‘doing the job’!! Most of the energy is wasted in scattering and absorption in other tissues. This leaves a lot of energy ‘floating’ around in the dermis potentially looking to cook something else. That leads to unwanted tissue damage!
So, we must mitigate against this rogue energy by cooling immediately after the treatment – not five or ten minutes later – immediately.
By doing so, we limit any possible damage to the surrounding tissues in the skin, which may lead to scar formation later. As with the pre-cooling, the amount of post-cooling depends on the energy fired at the skin – if you use a high fluence in a large area, then there will be a significant amount of energy deposited into it. This must be removed!
There is absolutely no doubt about this – cooling is critical in all photothermal treatments. We are deliberately trying to ‘burn’ some target tissue. We must mitigate against unwanted burning.
________________________________________________________________________ 253 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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