Thomas Fitzpatrick proposed a classification of skin type based on the efficacy of melanogenesis in response to ultraviolet exposure. This classification is based on personal history of sunburning and/or suntanning following 45-60 min of exposure to midday sun.
Fitzpatrick classification of skin type
I Always burns never tans
II Burns easily,tans with difficulty
III Rarely burns,tans easily
IV Never burns,tans
The Fitzpatrick classification is good predictor of melanogenesis in response to ultraviolet exposure;however,other stimuli of melanocytic function have not been correlated to this classification.For example,other important stimuli are inflammation,hemosiderin and free-radical formation.Various hormones have also been associated with stimulation of melanocytic function.
The effects of light on skin including laser light begins with absorption of incident light by chromophores.Melanin,hemoglobin,oxyhemoglobin and water are the dominant natural chromophores in the skin.The major determinant of differences in skin color between white and nonwhite is the amount of epidermal melanin.
Race as a determinate of skin color can be broadly broken down into five categories.There are obvious significant differences in skin color and thus melanocyte/melanosome/epidermal cell interaction even within geographic groups.Lancer proposed a "Lancer ethnicity scale" to take race into consideration when treating patients with laser resurfacing.
Lancer ethnicity scale (LES)
Geography Fitzpatrick skin type LES skin type
African V 5
Arabian III 4
Asian IV 4
North american II 3
Latin/Central/South American IV 4
Europe
-Ashkenazi Jewish II 3
-Northern european I 1-2
-Soutern european III 3-4
-Mediterranean III 3-4
-Nordic I-II 1
-Central eastern european III 2
-Celtic I 1
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