First things first – the melanin concentration (skin colour) is not related to the Fitzpatrick Scale…
The ‘Fitzpatrick Skin Scale’ was designed by a Californian dermatologist, Dr Thomas B. Fitzpatrick in 1975. He was routinely treating patients with potential skin cancers and wanted a way of classifying their potential for developing cancer and subsequent treatments. Dr Fitzpatrick developed his scale to assist in choosing the correct dose of UVA energy for PUVA treatments.
His scale assigns a number depending on the skin’s response to ultra-violet light – the main cause of skin cancer. It is NOT a skin colour scale!!
Unfortunately, the medical laser industry ‘hijacked’ his scale in the early 1980s when it was beginning to make an impact in medicine.
As a consequence, it has been mis-used ever since!
The reality is that we are all born with our ‘skin type’. I am a Fitzpatrick Type 2 – I ‘sometimes burn, tans minimally’ when exposed to UV light. If I am lucky enough to go on holiday in a sunny country (Covid-permitting) I will develop a decent tan after a few days of hot, red skin.
At that point my skin colour has changed significantly, BUT I AM STILL A TYPE 2!!!
Your skin ‘type’ (according to the Fitzpatrick Scale) does not change when your colour does. It is not unusual for clients/patients to return for treatments with a different skin colour. In fact, it is perfectly normal – but their skin type remains the same, at all times.
What makes this situation even more strange, is that most laser/IPL treatments don’t even deliver UV light energy, thereby rendering the Fitzpatrick number completely redundant.
Skin Colour Scale
It would be much more useful if there was a readily accessible skin colour scale, rather than a ‘reaction to UV light’ scale. In the past such a scale existed – this was the ‘von Luschan Chromatic Scale’. This scale was developed to identify racial skin colours and used 36 opaque glass slides to ‘measure’ the skin colour. Unfortunately, this method was not very accurate with too many discrepancies and it was abandoned in the middle of the 20th century.
Melanin Concentration = Skin Colour
What is needed is a device which can measure the concentration of melanin (skin colour), at any particular site, on any particular day, just prior to laser/IPL treatment. My colleague, PA Torstensson, designed such a device a few years ago using two laser diodes to make such measurements.
The concentration of melanin is the real issue here. Melanin absorbs light across the full visible spectrum resulting in heat generation. Obviously, the higher the melanin concentration, the more heat is generated in the basal layer, and, hence, the more likelihood of epidermal damage.
Another important issue is that the skin colour usually varies across a client/patient’s body – this means we must use different parameters if treating different body areas. Of course, their Fitzpatrick number is the same across the body…
The bottom line is that you must always base your laser/IPL treatments on the skin colour on the day your client/patient is being treated! If their skin is darker, use a lower fluence with more epidermal cooling.
Their Fitzpatrick Skin Type is irrelevant!!
Ciao for now,