Sebum Output as a Factor Contributing to the Size of Facial Pores

M. Roh; M. Han; D. Kim; K. Chung


The British Journal of Dermatology. 2006;155(5):890-894. 

In This Article

Summary and Introduction


Background: Many endogenous and exogenous factors are known to cause enlarged pilosebaceous pores. Such factors include sex, genetic predisposition, ageing, chronic ultraviolet light exposure, comedogenic xenobiotics, acne and seborrhoea. This study was an attempt to determine the factors related to enlarged pores.
Objectives: To assess the relationship of sebum output, age, sex, hormonal factors and severity of acne with pore size.
Methods: A prospective, randomized, controlled study was designed. A total of 60 volunteers, 30 males and 30 females, were recruited for this study. Magnified images of pores were taken using a dermoscopic video camera and measured using an image analysis program. The sebum output level was measured with a Sebumeter®.
Results: Using multiple linear regression analysis, increased pore size was significantly associated with increased sebum output level, sex and age. Among the variables, sebum output level correlated most with the pore size followed by male sex. In comparing male and female participants, males had higher correlation between the sebum output level and the pore size (male: r = 0·47, female: r = 0·38). Thus, additional factors seem to influence pore size in females. Pore size was significantly increased during the ovulation phase (P = 0·008), but severity of acne was not significantly associated with the pore size.
Conclusions: Enlarged pore sizes are associated with increased sebum output level, age and male sex. In female patients, additional hormonal factors, such as those of the menstrual cycle, affect the pore size.


The phrase 'skin pore' usually applies to the visible topographic features at the skin surface corresponding to enlarged openings of pilosebaceous follicles.[1,2] They appear as empty funnel-shaped structures or as cornified cylindrical plugs corresponding to comedones. Visible empty funnel-shaped pores are physiologically present in all individuals. Horny impacted pores are normally seen in the facial skin, especially on the nose and cheeks, but the appearance of pores differs among individuals. Many exogenous and endogenous factors such as sex, genetic predisposition, ageing, chronic ultraviolet light exposure, comedogenic xenobiotics, acne and seborrhoea are known to be responsible for enlarged pores.[3] Oily skin results from large quantities of sebum produced by the sebaceous glands, filling the follicular reservoir and leaking onto the body surface. On the face, greasy skin is shiny and may be accompanied by large pores, follicular plugs, sebaceous filaments and comedones. Various factors are known to influence sebum secretion and there is a consensus that sebum secretion rate declines with age.[4] It has been determined that after reaching maximum rates at around 20 years of age, sebum secretion steadily declines, in both men and women, over the entire succeeding life span. Generally there is no clear evidence that men produce larger amounts of sebum although men tend to have higher values.[5] Hormonal factors also contribute to the difference in sebum secretion. Androgen exerts a major effect on sebocyte proliferation and sebum secretion[6,7] and the level of receptors for 5α-reductase type 1 is significantly higher in sebaceous glands than in other skin structures.[8,9] Oestrogen counteracts the effect of androgen but with a much weaker potency. Environmental factors such as season, relative humidity and temperature are also known to influence sebum secretion.[10]

The attributes of oily skin are of significant cosmetic concern because some women complain of difficulty in applying make-up, as the skin surface is greasy and is often roughened because of enlarged pores and keratotic plugs. Various treatment modalities to reduce the size of the pores, such as intense pulsed light, retinoic acid cream, oral isotretinoin, isotretinoin iontophoresis and glycolic acid peeling have been used without much success.

The purpose of this study was to determine the factors related to enlarged pores. We assessed the relationship of sebum output, age, sex, hormonal factors and severity of acne with pore size.


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