Skin cosmeceuticals represent an interesting realm between dermatologic drugs and cosmetics. Traditional drugs are products designed to treat skin disease available only by prescription. On the other hand, cosmetics are used to scent, adorn, and color the skin without the intent of altering its structure or function. New understandings of skin physiology, novel raw materials, clever formulations, and increased consumer awareness of skin aging have resulted in a poorly defined category of dermatologics known as cosmeceuticals. Cosmeceuticals are of particular interest in the ethnic population, since skin ashiness, facial skin shine, antiaging photoprotection, and irregular pigmentation are of key importance. Improvement in all of these appearance related areas could only be achieved through an understanding of the ingredients combined to deliver an identified skin benefit. This chapter focuses on the use of cosmeceuticals in ethnic skin.
COSMECEUTICAL TREATMENT ALTERNATIVES
Cosmeceutical treatment alternatives for ethnic skin can be divided into the basic hygiene activities of cleansing and moisturizing and skin health activities consisting of photoprotection and skin lightening. The unique melanin distribution of ethnic skin creates formulation challenges for optimal skin functioning, since inflammation of any sort results in undesirable darkening of the skin color, known as postinflammatory hyperpigmentation. While mild skin irritation may be tolerable in minimally pigmented skin, since the resulting erythema is short lived and not accompanied by hyperpigmentation, any product-induced inflammation in ethnic skin may cause prolonged pigmentary change. Thus, cleansers designed to produce mild exfoliation and improve skin surface texture in Caucasian skin, may produce postinflammatory hyperpigmentation in African America skin. Similarly, antiaging moisturizers with hydroxy acids designed to induce edema and minimize facial fine lines in Caucasian skin may also produce pigmentary changes in African American skin. It is for this reason that the reader must understand unique ethnic skin needs in terms of cleansing and moisturizing while addressing important skin issues in terms of photoprotection and skin lightening.
Cleansing of the skin is important, both for optimal appearance and good hygiene. The cleansing of ethnic skin presents some unique challenges because of the adverse effects of over or under cleansing the skin. To understand how cleansing affects skin appearance, it is important to understand how the human eye assesses skin beauty. Visible light reaches the skin surface and is either reflected back to the eye from the stratum corneum or enters the skin and is then reflected back to the eye from collagen fibers, blood vessels, and melanosomes. In ethnic skin, the desquamating corneocytes contain pigment. This brown skin scale appears gray when viewed, as a result of the air interface behind the scale and gives rise to the term “ashy,” which is used to describe the appearance of dry skin in darker complected population. The term likens the skin scale to the gray appearance of ashes after combustible material has been consumed by fire. Ashy skin is equated with dry ...