Sebum production plays an important role in skin hydration by producing glycerol, which is necessary for an intact skin barrier. In addition, sebum supplies lipids to the surface of the epidermis that may aid in preventing transepidermal water loss (TEWL) (see Chapter 11). Excess sebum production produces oily skin, and in many cases, contributes to acne. With continuing advances in understanding the physiology and molecular biochemistry of sebaceous glands (SGs) and lipid metabolism, dermatologists may soon be able to elucidate the underlying aspects of sebum secretion and oily skin. This chapter will focus on the various known causes of oily skin and their implications, a new classification approach for determining the oily skin type, and the available treatments for oily skin as well as the efficacy of these treatments.
COSMETIC IMPLICATIONS OF OILY SKIN
Oily skin is a common complaint,1–7 especially in the adolescent age group.2 Those with moderate to severe oily skin complain of having to wash their face several times a day, looking shiny a few hours after washing, frequent streaking of facial foundation, and an inability to find a sunscreen that does not worsen perceived skin oiliness. These features of oily skin are disturbing to women and men alike and are perceived to be a serious cosmetic problem leading to a negative self-perception and possibly affecting social interactions. Clinically, oily skin presents as lipid-laden secretions resulting in a shiny appearance mostly over the T-zone area (forehead, nose, and chin)4 (Fig. 10-1). SGs become large leading to a condition known as sebaceous hyperplasia, which is characterized by 0.5 to 1.5 mm umbilicated papules found in the T-zone area of the face (Fig. 10-2). In addition, many patients with oily skin complain of large pores.8
Oily skin often appears shiny in the T-zone area in photographs.
Sebaceous hyperplasias are enlarged oil glands that look like a small papule with a central umbilication. They can be confused with basal cell carcinoma.
SGs are uni- or multilobular entities usually associated with hair follicles that, with hair follicles, form a structure known as the pilosebaceous unit. The number of SGs remains approximately the same throughout life, whereas their size tends to increase with age. SGs vary in size and are located throughout the body except the palms and soles. The highest concentration of SGs is found on the face and scalp, but few are found on the lips. (This is important because the lips have lower vitamin E levels than the rest of the face because of the lack of sebum.) Although they are most frequently associated with hair follicles, SGs are found in some non-hair-bearing ...