Page 245 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
Home-Use IPL Devices
These devices are often known as ‘HUDs’. They are usually low-fluence IPL units designed for use by individuals in their homes. Such devices are manufactured by companies like Phillips, Braun and NOOD, and sold across the planet. Many professionals assume that they do not ‘work’ properly, but, in fact, the clinical research does not agree with that assessment! So, we took the usual output parameters from these devices and applied them to our computer model.
Adapting the model to a ‘low fluence’ treatment regime yields a different set of results. In this scenario, the anagen follicles are not ‘killed’ outright. They are ‘stunned’ and assumed to enter a ‘catagen-like’ phase. The outcome of this approach is that follicles are never ‘killed’ and they may be capable of re-growth in the future, after treatments have ceased.
However, a study by Roosen et.al. appears to show that follicles which were forced into the ‘catagen-like’ state did not necessarily generate hew hairs in the subsequent anagen phase. This seems to indicate that the so-called ‘catagen-like’ state is not precisely a typical catagen state. Further research needs to be carried out on this issue since it is unclear what is occurring during this time.
Temporary Hair Reduction
When low fluence (< 10 J/cm2) treatments are carried out on HFs, it appears that the kill zone disappears. The entire dermal region becomes simply a stun and null zone. This will inevitably lead to a temporary hair reduction.
Low fluence, home-use devices (HUDs) can significantly reduce hair growth using a different approach (Roosen et.al., Town et.al. Emerson and Town, van Vlimmeren et.al.), for as long as the treatment sessions are continued. As yet, there is no substantive clinical evidence that low fluence treatments will permanently remove hair.
However, Town suggests that multiple treatments at low fluence may eventually ‘wear down’ the important anagen-inducing processes, either through physical damage to the DP, the hair matrix and/or HG, or through continued disruption to the signalling pathways. They suggest that follicles can be miniaturised by multiple treatments leading to finer hairs in future growth, once treatments have ceased. Gan and Graber agreed with these findings.
High Fluence vs Low Fluence Treatments
From clinical and histological studies, it appears that there are at least two ways to kill, or stunt follicles:
________________________________________________________________________ 245 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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