Page 48 - Chapter 3 - An Introduction to Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
Post-treatment
The main purpose of many light-based therapies is to induce some sort of change in the target using light and heat. Pre-cooling will help to reduce pain and tissue damage in the upper portion of the skin through direct cooling of the epidermis. But, the intended heating of the target tissues will also result in some unwanted heat energy in the skin. This must also be addressed properly.
Figure 17 - A 'KoolPak' ice pack - very useful for cooling the skin before and after laser/IPL treatments
Applying a water-based gel to the skin surface prior to treatments is a good idea. The water in the gel will help to remove heat from the skin rapidly. This is simple thermodynamics (look up the ‘Zeroth Law of Thermodynamics’ if you’d like to learn more about this)!
Laser Hair Removal – A Thermo-Chemical Process
Laser hair removal is one of the most popular treatments around the world today. Lasers and IPLs are used routinely to remove hair, with varying degrees of success. The treatment principle is based on the theory of Selective Photothermolysis – targeting the melanin in the hair follicle and heating it sufficiently to destroy the germ cells.
________________________________________________________________________ 48 Chapter 3 Laser/IPL Hair Removal
© The Laser-IPL Guys, 2022
Post-treatment cooling is also important. As the heat energy conducts throughout the dermis, some of it will reach the temperature/pain nerve endings – after the initial heating from the epidermal layer. This must also be mitigated by skin surface cooling.
Applying ice-packs (see the ‘KoolPak’ on the left) or similar will help to suck the heat energy out of the skin rapidly.
Air is a poor heat conductor, so water-based cooling should always be used to maximise the cooling effects (water conducts heat about 20 times more efficiently than air!).