Skin type, hair color, and freckles are predictors of decreased minimal erythema ultraviolet radiation dose.
In a group of 190 white healthy subjects the skin type classification method was found valuable for differentiating subgroups with various degrees of sun sensitivity (except for 33% with borderline or unclassifiable skin type). Sun-sensitive skin types I and II were significantly more common among persons with light hair color or freckles, or both (p less than 0.001). In each skin type category the proportion of subjects with a minimal erythema dose (MED) lower than the median MED of the entire group (%LMED) decreased significantly with increasing skin type number, and distinguished between skin types I through III better than did their mean MED values. Independent predictors of %LMED were skin type and hair color. The contribution of freckles to %LMED was skin type dependent. Age, sex, or eye color had no independent effect on %LMED. The association of skin types I and II, red or blond hair, and freckles with decreased MED may reflect genetically controlled predominance of pheomelanin (a photosensitizing molecule) in the skin of subjects with these phenotypes.
Azizi
E
E
Department of Dermatology, Chaim Sheba Medical Center, Tel Hashomer, Israel.
Lusky
A
A
Kushelevsky
A P
AP
Schewach-Millet
M
M
D000328:Adult; D004307:Dose-Response Relationship, Radiation; D004890:Erythema / Q000209:etiology*; D005260:Female; D006200:Hair Color; D006801:Humans; D008297:Male; D008548:Melanosis; D010641:Phenotype; D012880:Skin Pigmentation; D014466:Ultraviolet Rays / Q000009:adverse effects*