Ethnic differences in hair

Key points

Understanding the differences in hair structure and haircare practices in African Americans compared with white, Hispanic, and Asian patients is essential when evaluating and treating hair concerns in this population.
Structural characteristics of Afro-textured hair include a retroverted hair bulb, an S-shaped follicle, and an elliptical-shaped hair shaft.
Hairstyles such as tight buns and ponytails, braids, dreadlocks, and weaves increase the risk of developing traction alopecia, which is present in approximately one-third of women of African descent.
Both scarring and nonscarring alopecias can affect the skin of non-white patients. However, some types of hair loss appear to be more common in men and women of African descent, including traction alopecia, acquired trichorrhexis nodosa, seborrheic dermatitis, alopecia areata, central centrifugal cicatricial alopecia, folliculitis decalvans, acne keloidalis nuchae, and dissecting cellulitis.
Various treatment options exist for alopecia in patients with skin of color, and the choice of treatment depends on the underlying diagnosis.
Effective treatment options for androgenetic alopecia include topical minoxidil and low-level laser light therapy in men and women and oral 5α-reductase inhibitors in men.

Introduction

Non-white patients, specifically those of African descent, have unique hair characteristics and haircare practices. Understanding the differences seen in the hair of African Americans compared with white, Hispanic, and Asian patients is essential when evaluating and treating hair concerns in this population. Hair is classified into three types: African, Asian, and Caucasian ( Fig. 2.1 ). Each of these differ in structure, growth rate, and density. This chapter will focus on Afro-textured hair.

Fig. 2.1, Structure of Hair Follicles by Ethnicity.

The structural characteristics of Afro-textured hair include a retroverted hair bulb that resembles the shape of a golf club, an S-shaped follicle, and an elliptical-shaped hair shaft (level of evidence: 2b). The retroverted hair bulb is responsible for the curly configuration of Afro-textured hair (level of evidence: 2b). One theory is that the curly nature of the hair prevents even distribution of sebum along the hair shaft, leaving the scalp oily and hair shaft prone to dryness (level of evidence: 5). Additionally, Afro-textured hair is lower in density and has a slower growth rate compared with Caucasian hair (level of evidence: 5), regardless of scalp region or gender (level of evidence: 2b). It is important for dermatologists to understand the unique features of Afro-textured hair in addition to cultural haircare practices and hairstyles, as this may facilitate compliance with treatment and help discern practices that may negatively affect scalp disease.

Cultural differences in persons with skin of color

Societal beauty standards have often valued the European aesthetic, which can negatively affect Black women’s perception of their own body image (level of evidence: 2b). In a research study conducted by Awad et al., a cohort of black women were surveyed on body image concerns. Researchers found that hair was the most important body image domain. Participants reported that their hair influenced their self-confidence. Additionally, the pressure to adhere to societal and personal beauty standards led to significant sacrifices of time and money. Recognition of these factors can help dermatologists understand why patients may be hesitant to change haircare practices or styles, even if recommended as part of a hair-loss treatment regimen.

Exercise also affects haircare practices. A study completed by Ahn et al. found that women of African descent modified their hairstyles to accommodate physical activity. This included wearing braids, a ponytail or bun, or the use of a scarf or hair wrap (level of evidence: 2b). Additionally, 18% of these women exercised less often to avoid sweating out hairstyles.

When evaluating a patient with hair loss, the place to begin is with a thorough hair-loss history. In the case of patients with Afro-textured hair, asking the right questions is paramount ( Pearl 2.1 ). Onset and type of symptoms and the affected location of the scalp are important for all patients with hair loss, but for those with Afro-textured hair, a number of specific haircare questions must be included: use of chemical relaxers, traction-related hair styles (hair weaves, braids, locks) (level of evidence: 5), ^, frequency of hair washing, use of heat for straightening, and other product use. Moreover, clinicians should approach these encounters with empathy and acknowledge the significant psychosocial implications that may accompany hair loss (level of evidence: 5).

PEARL 2.1:

Obtaining a hair history and completing a thorough examination of the scalp are essential in diagnosing alopecia in patients with Afro-textured hair.

Common forms of hair loss that affect patients with skin of color

Although we will focus on androgenetic alopecia (AGA), several other forms of hair loss are important to discuss, as they may be in the differential diagnosis of AGA or complicating the treatment of AGA ( Pearl 2.2 ).

PEARL 2.2:

It is important to successfully treat inflammatory scalp disease prior to beginning any topical treatments for pattern hair loss, because the presence of inflammation can complicate treatment.

Nonscarring alopecias

Nonscarring alopecias are common and can be associated with hairstyles and haircare practices. With prompt diagnosis and treatment, hair regrowth is attainable. In this section, we present several nonscarring alopecias that may be seen in patients with Afro-textured hair.

Androgenetic alopecia or pattern hair loss

Androgenetic alopecia (AGA), also known as female or male pattern hair loss (FPHL/MPHL), is a common nonscarring alopecia with a characteristic pattern distribution. The population frequency and severity increase with age in both men and women. Patients typically experience slow, progressive hair loss, and associated symptoms may include pruritus and trichodynia (level of evidence: 5). The prevalence of pattern hair loss is highest in Caucasian males and females compared with Asians (level of evidence: 2b). There is currently no data on the prevalence of pattern hair loss in men and women of African descent.

FPHL presents as a reduction in scalp hair density, primarily in the vertex and frontal scalp. This is caused by follicular miniaturization and an increase in vellus follicles (level of evidence: 2b). The vellus hair follicles have a reduced anagen cycle, leading to short, fine hair shafts (level of evidence: 5). As the hairs become thinner, the central part appears wider on the frontal scalp compared with the occipital scalp (level of evidence: 5). Women may present with diffuse thinning in the vertex scalp, thinning that is more prominent in the frontal scalp, resulting in a “Christmas tree pattern” (level of evidence: 5), or bitemporal thinning. Although bitemporal hair loss is common in FPHL, it can also be seen in traction alopecia, telogen effluvium (TE), alopecia areata (AA), frontal fibrosing alopecia (FFA), central centrifugal cicatricial alopecia (CCCA), and seborrheic dermatitis (level of evidence: 5). In FPHL, the frontal hairline is typically spared ( Pearl 2.3 ). The etiology is likely caused by an interplay of genetics, hormones, and environmental factors. Although some women with FPHL have excessive androgen production, others have normal levels of androgens, leaving the exact role of androgens in FPHL poorly understood.

PEARL 2.3:

Bitemporal hair loss can be a manifestation of pattern hair loss, traction alopecia, telogen effluvium, alopecia areata, frontal fibrosing alopecia, central centrifugal cicatricial alopecia, or seborrheic dermatitis.

MPHL presents as hair loss in the temporal, midfrontal, or vertex scalp. Dihydrotestosterone binds to androgen receptors in hair follicles, which leads to suppression of hair growth by miniaturization of hair follicles (level of evidence: 5). The severity and areas of involvement are variable. Different regional patterns of hair loss are caused by differences in follicle sensitivity to dihydrotestosterone.

The differential diagnosis of pattern hair loss is extensive and includes CCCA, FFA, folliculitis decalvans (FD), and, rarely, dissecting cellulitis (DC). The presence of inflammation or scarring is not consistent with pattern hair loss and should prompt consideration of another cause of alopecia. Underlying medical conditions such as eating disorders leading to malnutrition, iron deficiency, or thyroid dysfunction should also be explored, as they may result in diffuse hair loss that may appear more pronounced on the vertex scalp caused by mild underlying pattern hair loss (level of evidence: 5). The goal of treatment is to prevent progression of hair loss and reverse the miniaturization process. Treatment options that have proven to be effective in randomized controlled trials include topical minoxidil and low-level laser light therapy in men and women, and oral 5α-reductase inhibitors in men (level of evidence: 1b). Other off-label treatment options for women include oral 5α-reductase inhibitors, as well as antiandrogen therapies such as spironolactone, cyproterone acetate (outside the United States), and flutamide (level of evidence: 5). In the twenty-first century, low-dose, oral minoxidil has been gaining favor for the treatment of pattern hair loss in both men and women. Scalp hair restoration may be performed for men and women with severe cases (level of evidence: 5).

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