posted by ISHRS on August 1, 2007

What are the characteristics of scalp hair that contribute to a person’s unique appearance?
The characteristics commonly noted are:
Color-blond, red, brown, black and varying shades of each.
Caliber (diameter of hair shaft)-fine, medium, or thick in cross-section.
Geometric property-straight, wavy, curly, frizzy.
These commonly noted hair characteristics are often associated with other features that contribute to unique appearance. For example:
Light blond straight hair and fair skin in a person of Scandinavian heritage.
Dark, wavy hair and olive skin in a person of Mediterranean heritage.
Black straight hair and light brown skin in a person of East Asian heritage.
Black tightly curled hair and dark brown or black skin in a person of African heritage.
Hair characteristics are important in establishing a unique identity for each individual person. Genetic heritage is reflected to variable degrees by hair characteristics; the genetics of inheritance for characteristics such as hair color are not fully understood. Hair color can also change in tone and shade throughout a person’s lifetime, most markedly changing from “color” to “gray” as the person ages and pigment is lost from the hair shafts.
Hair characteristics are essential considerations in the planning and undertaking of hair transplantation. For the physician hair restoration specialist, hair characteristics are not isolated phenomena, however. They are inter-related with other features of a person’s individuality such as skin color, color contrast between hair and scalp skin, hair density (number of hairs per square centimeter of scalp skin), elasticity of scalp skin, and size and shape of the patient’s head as a determinant in planning for placement of transplanted hair grafts (See Surgical Hair Restoration).
The unique characteristics of each patient-including hair characteristics-are assessed separately and in their inter-relationship with one another when hair transplantation is planned by the physician hair restoration specialist in consultation with the patient. A patient’s expressed wishes regarding time, extent, cost and anticipated outcome of hair transplantation are factored into planning of the procedure.
Hair Characteristics and the Appearance of a Sparse or Full Head of Hair
Hair characteristics contribute to the appearance of “fullness” of scalp hair, whether or not there has been any hair loss. Perceived bulk or “fullness” is not necessarily a matter of have “more” hair. For example, a fair-skinned person of Caucasian ancestry with straight light blond hair may appear to have sparser scalp hair than a light brown-skinned person of East Asian (Chinese, Japanese Korean) ancestry who has straight black hair. However, a count of scalp hairs per square centimeter of scalp (hair density) reveals that the person of East Asian ancestry has fewer hairs per square centimeter of scalp than the person of Caucasian ancestry. This is no surprise; hair density has a genetic basis and is an inherited trait.
What, then, accounts for the appearance of greater fullness in the scalp hair of the person of East Asian ancestry? The answer is-hair caliber, another inherited trait. The straight, black hair of the East Asian person is thicker in cross-section than the straight blond hair of the Caucasian person. The thicker diameter of the straight black hair increases hair bulk and the appearance of greater hair density. When hair loss occurs in the person of East Asian ancestry, the illusion of greater hair density may be lost.
Hair restoration in areas of hair loss must take account of the inter-related characteristics of the patient’s hair.
The characteristics of curl and wave also contribute to an appearance of hair bulk or fullness. When densely curled or “frizzy” hair is transplanted to areas of hair loss, an appearance of fullness may be created with fewer grafts than would be required to achieve an appearance of fullness with straight, fine hair.
Contrast between the color of transplanted hair and the color of underlying scalp skin can substantially influence the appearance of fullness or sparseness. In black-skinned patients, for example, there may be little contrast between the color of hair and the color of scalp skin. This contributes to the appearance of greater hair density because scalp skin does not vividly “show through” the curls of transplanted hair.
Hair Characteristics and the Esthetics of Hair Transplantation
Hair transplantation is a science-based medical and surgical procedure that the patient undergoes to achieve an outcome of esthetic improvement. The hair transplant physician must, therefore, be a master of surgical esthetics as well as surgical technique.
Esthetic improvement by today’s standards of hair transplantation is not merely hair restoration, but hair restoration with a “natural” appearance. That is, the area of hair restoration should look, as much as possible, as the area might look if no hair had been lost.
Hair characteristics are among the most important considerations in achieving the goal of natural appearance in hair transplantation. Hair at different sites on the patient’s head has characteristics useful for specific purposes in transplantation. Hair caliber (diameter of the hair shaft) is one of the most important characteristics. Hairs of heavier caliber found at the back of the scalp may be harvested and used to achieve fullness and bulk in mid-scalp areas of hair loss. Hairs of finer caliber, such as those found near the temples, may be harvested and used as grafts to create the all-important hairline. Where the hairline should be placed can be a challenging esthetic decision that calls for the skill and experience of the physician hair restoration specialist-a decision that is based on elements such as extent of hair loss, shape of the patient’s head, the likelihood of further hair loss in the future that will require additional hair restoration, and the patient’s wishes regarding outcome.