Page 246 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
High fluence (20 – 60 J/cm2)
Significant thermal denaturation of entire follicle structure;
Destroys all, or most, of the stem cells in the bulge region and ORS;
Pushes HF into catagen, if fluence below threshold;
New hairs grow back as thinner.
This often occurs when deeper HFs are treated with insufficient fluence.
Once every 6 to 8+ weeks
Can kill all follicles in 6 to 8 sessions, if fluence is sufficiently high for the target depths
Low fluence (< 10 J/cm2)
Much more subtle, less cellular damage induces a “catagen-like” transition, although not precisely;
Appears to also affect the chemical/signalling pathways!
Targets the melanogenic region in the hair matrix, above the dermal papilla. Either heated melanin in the DP or simply heat conduction into it from the matrix induces apoptotic cells in the DP, matrix and hair germ.
2 to 3 times each week
Takes many sessions to ‘kill’ all follicles, if at all.
Much more likely to push the HF into a ‘catagen-like’ phase and maintain hair reduction.
Good for removing hairs between sessions – this is often requested by clients
Table 48 - High fluence vs low fluence hair reduction treatments (References: Town et.al., Roosen et.al., Marijke et.al., Gan and Graber, Emerson and Town.)
Clinical studies and histological research (Table 48) indicates that low fluence treatments of HFs induces a “catagen-like” transition of the affected HFs. Note that the typical statement is “catagen-like” – most researchers use this term rather than “catagen”. The reason for this is that the low fluence treatments induce apoptosis of some of the HF cells in the DP, which forces the follicle into a regressive state – similar to catagen. However, some studies show that whilst the HF transitions into the subsequent telogen state, the next sequence of events often may not follow the typical telogen-to-anagen transition. Some researchers state that hairs do not always appear to grow in subsequent anagen phases (Roosen et.al.).
This indicates that the forced transition of the follicles into the ‘catagen’ state does not imply that the growth cycle continues as before. In fact, the research appears to indicate that, in many instances, the normal cycle is ‘disrupted’ by this unnatural process.
________________________________________________________________________ 246 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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