1.1. Introduction
Since the advent of chemical hair relaxers in the 1940s, the trend among women of African descent to achieve long, straight, socially desirable hairstyles has fluctuated, but nonetheless remained very popular. In studies discussing hair relaxer use among African-American women, prevalence of those who endorsed having ever using relaxers ranged from 71% in a group of 1693 African-American women from Detroit
[1], to 95% in the Black Women’s Health Study, a prospective cohort of 59,000 self-identified Black American women
[2]. Reasons cited for the use of relaxers include increased hair manageability
[3], decreased work of combing
[4], and improved self-esteem
[5].
Hair relaxing or “perming” has generally been viewed as a way for Black women to assimilate into Eurocentric standards of beauty and professionalism. In fact, relaxer use is highest in the Southern states, a region where, historically, resistance to de-segregation and discrimination against Black individuals was very widespread
[6]. Many women here may have felt increased social pressures to blend in and de-emphasize their African traits. A trend toward more natural or “Afrocentric” hairstyles briefly re-appeared in the late 1960s and 1970s, during the historic Black Power movement, when women who wore their natural hair texture were seen as a making a radical political statement
[7]. This movement was short lived, however, and popular movies and television shows throughout the decades have continued to perpetuate the idea that Black hair is more beautiful when chemically altered by predominantly casting Black women with long, flowing, straight hair
[8]. Additionally, in many professional contexts, having Afro-textured hair is associated with negative stereotypes and lower expectations, with Eurocentric hairstyles more frequently adopted in the workplace in order to facilitate social acceptance
[5].
Despite these social pressures, the use of relaxers has been on a general decline over the past decade, as the wearing of natural hair has become more acceptable, and many have begun to realize the harmful side effects that frequent chemical exposure may cause
[6]. In fact, consumer studies have demonstrated that between 2008 and 2012, the market for hair relaxers declined by twenty percent
[9]. There have been small pockets of resistance to the modern natural hair movement, with Black women who tried to “go natural,” only to find the process confusing and extremely time consuming
[10]. Understandably, since many women have worn relaxed hair for the majority of their lives, they may find natural curly hair difficult to manage as they are not used to the hairstyling process and perhaps the additional time and products needed to be able to style and maintain their curls
[7]. Still, there is a general trend toward less hair relaxer use, and more natural or “protective” hairstyles, as will be discussed in the subsequent pages.
1.2. Associated Risks
Permanent straightening of Afro-textured hair can only be accomplished through the breaking and rearranging of disulfide bonds in the hair shaft
[11]. The original method of hair relaxing, also called lanthionization, involved ingredients such as sodium hydroxide or potassium hydroxide mixed with potato starch
[11]. Modern curl relaxers can be divided into lye and no-lye formulations, with lye relaxers most common in professional hair salons, and no-lye more popular for at-home use
[12]. Lye-based relaxers are found to penetrate the hair shaft more quickly, resulting in rapid straightening and reduced susceptibility to scalp dryness and irritation than the no-lye relaxers
[11]. The most frequently cited risks associated with the use of hair relaxers included hair damage, skin irritation, carcinogen exposure, endocrine-disrupting chemical exposure, hair loss, and lack of exercise-friendly hairstyle options.
The chemicals used during lanthionization are extremely alkaline. Not only does this pose a risk for chemical skin burns, but when left on the hair too long, relaxers begin to digest the hair itself
[13]. Additionally, relaxer use results in a decreased sulfur content of the hair, which can lead to weakening, increased fragility, hair breakage, and thinning
[14]. In a study of 715 African-American women aged 18 and over, 90% of women experiencing hair breakage reported using chemical treatments. Of the women who did not report breakage, they endorsed having a less involved grooming process with fewer products, fewer appliances, and longer intervals between straightening treatments, if used at all
[15].
The potentially carcinogenic nature of hair relaxers is still being researched, but there have been several studies demonstrating an association between regular use of hair relaxers and tumorigenesis. Numerous chemicals present in hair relaxer formulations have been found to be carcinogenic in animal studies
[9] and are hypothesized to increase cancer risk via exposure to hormonally active or endocrine-disrupting chemicals through dermal absorption
[2]. Use of relaxers and hair oils have been associated with early menarche, a risk factor for breast cancer
[2], and duration of relaxer use was positively associated with risk of uterine leiomyomata, also known as fibroids, another hormone-dependent disease process
[16]. In a large case study of 2998 women with breast cancer, overall duration of relaxer use > 10 years and use of relaxers before age 12 was significantly associated with larger tumor size
[17]. Another study found little evidence to support an association of overall hair relaxer use with risk of breast cancer but did find an association of heavy use of lye-based relaxers with increased risk of ER+ breast cancer
[2].
When women with chemically relaxed hair complain of “hair loss,” they are most often describing hair breakage resulting from overprocessed and brittle hair strands
[11]. There is, however, substantial debate as to the role chemical hair relaxers play in the disease processes of hair loss disorders such as Central Centrifugal Cicatricial Alopecia (CCCA), the most common type of scarring alopecia in this population
[18]. This type of alopecia, formerly known as “hot comb alopecia,” begins at the crown and vertex, and progresses centrifugally, leaving behind a shiny smooth scalp with follicular dropout
[18]. Although the relationship between chemical relaxers and CCCA is uncertain, several case studies have been published linking the two together.
A study on 1018 patients presenting to an alopecia clinic demonstrated that patients with cicatricial alopecia were significantly more likely to report any previous chemical hair straightening than patients with non-cicatricial alopecia, and that patients with CCCA reported a significantly higher cumulative exposure to chemical straightening than controls
[19]. In a prospective study by Uhlenhake et al.
[18], biopsies were examined from subjects at random without clinical evidence of alopecia, but who reported use of either chemical relaxants or thermal straighteners within the past month. Interestingly, peri-infundibular lymphocytic inflammation and concentric infundibular fibrosis, some of the histopathologic findings characteristic of, but not necessarily unique to CCCA, were found in all biopsies
[18]. These data suggest that there may be a histological prelude to the clinical signs of CCCA and lends plausibility to the association between relaxer use and scarring alopecia. It is also important to note that some studies found no association between relaxer use and CCCA
[20], or a weak, but statistically insignificant association
[21], further suggesting that more studies are needed to elucidate the true relationship between the two.
Another less commonly discussed relationship, but one that has profound health implications, is the exercise-prohibitive nature of chemically relaxed hairstyles. An estimated 80% of African-American women are overweight or obese, so the avoidance of exercise due to one’s hairstyle could be a notable public health challenge
[22]. In a study on 61 women of self-reported African, Afro-Caribbean, or African-American race, 18% of women stated that they exercised less than they would like because of their hair, for fear of “sweating out” hairstyles, and due to the time needed to restyle hair
[23]. Another study, this time on 1558 self-identified African-American women from Detroit, MI, found that in adulthood, women who used chemical relaxers at least two times per year were 10% less likely to report intense physical activity compared to their counterparts reporting rarely/never use
[24], suggesting this may be implicated as a contributor to the poor cardiometabolic health outcomes among Black/African-American women.
1.3. Recommendations
Several recommendations have been proposed in response to the research conducted on chemically relaxed hair to ensure the process is carried out in the safest and least damaging way possible. It is important for dermatologists and other health care providers to be knowledgeable of these recommendations in order to best advise their patients. First off, relaxers are best applied by experienced professionals with training in the appropriate application method and processing time
[25]. The condition of the client’s hair and scalp should be evaluated prior to application, and if the scalp is in any way compromised, relaxer use should be avoided, even if a base is used
[14]. Thin and/or porous hair process faster and, therefore, relaxer should be left on for as little time necessary to achieve the desired results
[14]. Careful application to the new growth only and deep conditioning treatments can help prevent breakage
[26]. Advice for how frequently to relax hair varied from every six to eight weeks
[5] to eight to 12 weeks
[27], with the general theme being that if treatments are applied too frequently, the risk of hair damage and breakage is increased. Following hair relaxation, high-tension styles
[28], as well as excessive combing or styling
[11] should be avoided to prevent traction alopecia (TA) and excessive breakage, respectively. TA will be discussed more in depth in the section titled “Traction Hairstyles” below.