Page 65 - Chapter 3 - Fundamentals of Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
The Clinical Endpoints
Almost every photothermal treatment will generate a number of clinical endpoints. Hair removal is no different, but it can vary between different devices. It certainly varies with parameters, especially fluence.
In a perfect scenario, we would prefer to see these endpoints at a short time after the treatment – usually a few minutes. If they appear too quickly, that may suggest too high a fluence was applied. The two main clinical endpoints to look out for are:
Perifollicular erythema or adjacent erythema
Erythema means ‘reddening’ and is caused by an expansion of local blood vessels. It is a sign of the inflammatory response of the skin following some trauma. Laser/IPL treatments are ‘traumatic’ to the skin, which will instigate the natural wound- response mechanisms.
When the follicles are heated to an extent that cellular damage occurs, there is a high probability of erythema, localised around the follicles – hence ‘perifollicular erythema’. You may see a more generalised erythema in the area around the treatment region – this is also quite normal and will usually disappear within a few hours (less than 24).
Oedema
Oedema is the localised swelling which often occurs soon after laser/IPL treatments. However, sometimes, it is very subtle and can be difficult to spot
In both of the above situations, excessive fluences will stimulate too much erythema and oedema – usually soon after the treatment. That should indicate strongly that you are using too much fluence!!
With some high-powered diode lasers the hairs can be effectively ‘wiped’ off the skin using a tissue or cloth. This appears to be due to steam formation inside the follicle which ruptures the hair shaft from the follicles. However, this may only occur in telogen hairs which are not rooted to the dermal papilla, and, therefore, tend to be much higher in the follicle canal. This does not mean that the treatment has been successful since we are not targeting the telogen hairs.
In many situations, the hair shafts are vapourised by the energy. This is quite evident by the smell of burnt hair in the treatment room (which itself represents a potential health hazard!) It tends to be unavoidable and so a good ventilation system is required to minimise inhalation of these burnt tissue components by staff and customers alike (see the next Section on ‘Plume in the air’).
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