Regional and seasonal variations in facial sebum secretions: a proposal for the definition of combination skin type.
OBJECTIVE
Facial sebum secretions are known to change under various circumstances. Facial skin types have been categorized as oily, normal, dry, and combination types. However, these have been evaluated subjectively by individuals to date, and no objective accepted standard measurement method exists. The combination skin type is most common, but its definition is vaguer than the definitions of the other skin types.


METHODS
We measured facial sebum secretions with Sebumeter. Sebum secretions were measured at five sites of the face seasonally for a year, in the same volunteers. Using the data obtained we developed a set of rules to define the combination skin type.


RESULTS
Regional differences in sebum secretion were confirmed. Sebum secretions on forehead, nose, and chin were higher than on both cheeks. Summer was found to be the highest sebum-secreting season, and seasonal variations were found in the T- and U-zones. A mismatch of skin type in the T- and U-zones in more than two seasons appears to be close to subjective ratings of what is described as the 'combination' skin type.


CONCLUSIONS
We showed that the face shows definitive regional and seasonal variations in sebum secretion. To define the combination skin type, seasonal variations in sebum secretion should be considered in addition to regional variations.
Youn
Sang Woong
SW
Department of Dermatology, Seoul National University College of Medicine, Gumi-dong, Bundang-Gu, Seongnam, Kyounggi-do, Seoul, Korea. swyoun@snu.ac.kr
Na
Jung Im
JI
Choi
Sun Young
SY
Huh
Chang Hun
CH
Park
Kyoung Chan
KC
D005145:Face; D005260:Female; D006801:Humans; D012016:Reference Values; D012621:Seasons; D012629:Sebum / Q000378:metabolism*; D012879:Skin Physiological Phenomena; D011795:Surveys and Questionnaires