Page 62 - Chapter 3 - An Introduction to Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
is used, then the average absorption coefficient drops to approximately 75 cm-1 with an equivalent wavelength of 950nm, while a 800-1200nm range yields a coefficient of 46.4 cm-1 with an equivalent wavelength of 1090nm (closer to the Nd:YAG wavelength). Using these wavebands would require higher incident fluences to account for the lower absorption by melanin.
Dormant Follicles
In virtually all situations you will encounter ‘dormant’ follicles. These usually don’t become active until triggered by something – trauma, hormonal changes, medicines etc. No light-based therapy will affect these follicles, until they are active.
As a consequence, we can never guarantee a “100% removal” simply because the dormant follicles may begin growing at any time after the treatment.
Epidermal Complications
There are a number of potential complications which can occur during photothermal treatments in the epidermis:
Indication
Precaution
Post treatment
Recovery
Hyperpigmentation
Hypopigmentation
Pre-cooling of epidermis
None
3-9 months
Crusting
Pre-cooling of epidermis
Post cooling, infection prevention
1-2 weeks
Blistering
Pre-cooling of epidermis
Post cooling, infection prevention
1-4 weeks
Pre-cooling of None (bleaching epidermis cream)
3-9 months
Table 14 – Epidermal Complications following light treatment of the skin
Note – The risks increase with darker skin types!
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