Chapter 57: Laser Treatment of Asian Skin

INTRODUCTION

Ethnic skin is often classified by the Fitzpatrick Skin Type classification with a scale that ranges from type I (ivory white skin) to type VI (dark brown skin) Table 57-1. Asian skin color is often characterized as types III to V. This reflects the person’s complexion and tolerance to sunlight, which is determined by the melanin content and melanosome dispersion. It is well established that there are no racial differences in the number of melanocytes.¹ Melanosomes in keratinocytes of light skin as in Caucasians are distributed as membrane-bound clusters, whereas the melanosomes in keratinocytes of dark skin as in African individuals tend to be distributed individually.² A study analyzed the melanosomes extracted from the epidermis in subjects of different skin types from various ethnicities. Epidermal melanin content is significantly greater in chronically photoexposed skin than it is in corresponding photoprotected skin (up to twofold). Analysis of melanosome size revealed a significant and progressive variation in size with ethnicity: African skin having the largest melanosomes followed in turn by Indian, Mexican, Chinese, and European.³ Skin pigmentation is strongly influenced by both the amount and composition of the melanin in the epidermis. Variation in melanosome size may also play a significant role.

The function of melanin in the skin is to absorb and scatter rays of ultraviolet (UV) light. The larger, individually dispersed melanosomes have a higher melanin content and are able to absorb more UV light energy than the aggregated, smaller melanosomes with less melanin content found in fair-skinned white subjects.⁴ This means that the degree of protection corresponds to the degree of pigmentation. This sun protection offers significant prevention of photoaging, which is the cosmetic advantage of skin types IV to VI. The downside is that skin of color has a tendency to develop hyperpigmentation or hypopigmentation. Indeed, pigment disorders are one of the most frequent concerns in skin types IV to VI.⁵ Although melanin protects skin from UV radiation, all skin types with prolonged sun exposure develop clinical abnormalities, consisting of textural changes and hyperpigmentation.⁶

Each culture has different standards of what it considers to be beautiful. Therefore, a clear understanding and awareness of the patient’s perception of beauty is essential. In Asian culture, flawless fair skin free of scars and pigment is thought to ...