Hair cosmetics, styling, and processing

Background, definitions, and history

The desire for healthy hair is evolutionary, as the cosmetic appearance of hair is a primary indicator of youth (level of evidence: 5). Hair is considered the healthiest when it lacks damage, whether self-inflicted or environmental. In 2016, the US beauty industry had an estimated revenue of 62.46 billion US dollars (level of evidence: 5). The leading worldwide cosmetic manufacturer in 2019 was L’Oreal, with worldwide headquarters located in France; the company made approximately 33.4 billion US dollars that year (level of evidence: 5). In 2018, the global haircare industry was valued at 87.9 billion US dollars. In addition to improving hair appearance in the general population, hair cosmetics, styling, and processing have a role in altering the appearance of the hair and scalp in a way that those with hair loss value. For example, patients with androgenetic alopecia (AGA) may turn to the beauty industry for products to minimize and conceal hair loss. Therefore, a firm knowledge base of hair cosmetics is essential for the assessment and treatment of these patients. In this chapter, we will review the fundamentals of healthy scalp and hair follicle maintenance, styling techniques, and hair processing options. Furthermore, we will emphasize their utility in the treatment of patients with AGA.

Indications and patient selection

Within the United States in 2021, routine hair and scalp hygiene and styling products were readily available and routinely used in the general population. However, a thorough understanding of hair cosmetics, styling, and processing requires individuals to also understand the concept of weathering. Weathering is a hair shaft process that results in hair damage from root to tip and includes decreased shine, elasticity, and, ultimately, breakage (level of evidence: 5) ( Pearl 5.1 ). ^, There are two types of weathering: natural and accelerated. In the process of natural weathering, the cuticle is worn away over time from hair brushing, combing, or other physical haircare maintenance techniques. Accelerated weathering includes damage to the hair’s cuticle and cortex proteins ( Fig. 5.1 ). ^, Those with long hair often demonstrate more severe weathering caused by repetitive injury of the hair shaft over time (level of evidence: 5). Processes that weaken hair fiber integrity and contribute to accelerated weathering include heat styling and chemical processing such as bleaching and permanent waving (level of evidence: 5). ^, Processes such as straightening, bleaching, and perming alter the protein structures of hair, causing irreversible damage (level of evidence: 5). ^, Other environmental factors in weathering include prolonged exposure to sunlight, resulting in loss of tensile strength, color changes, embrittlement, and split ends (level of evidence: 5). Sunlight exposure causes proteins and lipids to undergo degradation via a reaction between aromatic amino acid species and ultraviolet light, which produces reactive oxygen species such as hydrogen peroxide, hydroperoxides, and singlet oxygen. Overall, weathering of the hair fiber is expected over time in those with and without hair and scalp disease.

In addition to the general population seeking hair cosmetics for hygiene and to managing weathering, those with hair and scalp disease may also turn to the beauty industry for solutions. Patients with excessive sweat, oil, dirt, or hair product use may find regular hair and scalp hygiene especially helpful for follicular aesthetic appearance and prevention of the development of scalp diseases such as dandruff, seborrheic dermatitis, or folliculitis. Those with hair or scalp disease such as psoriasis, atopic dermatitis, dermatomyositis, or tinea may find that perfecting a hair and scalp hygiene routine along with personalized styling is important for overall disease management. Furthermore, cosmetic products are the foundation of treatment for those with hair breakage such as trichorrhexis nodosa and trichoptilosis ( Figs. 5.2 and 5.3 ).

Those with AGA may find unique cosmetic benefits in styling and camouflaging to disguise hair thinning. In AGA, hair follicles are miniaturized, which contributes to the overall appearance of lower hair density in affected scalp regions. Additionally, it has been proposed that the disease process, which results in reduced follicular fiber diameter, allows for increased vulnerability to fracture and increased weathering of hair fibers (level of evidence: 5). ^, Those with early and mild androgenetic alopecia may find that the at-home beauty industry offers sufficient cosmetic and styling options. Those with more progressed AGA will likely need the help of dermatologists and professional stylists to camouflage hair loss as part of a comprehensive management plan.

Of note, patients with a history of contact dermatitis may find the hair and scalp cosmetics industry difficult to navigate given the numerous ingredients found in products. Routine patch testing or patch testing within a tertiary care center may be required to finesse product selection (level of evidence: 5). When managing patients with alopecia, physicians must recognize that hair cosmetics, processing, and styling options are unique to each patient as product choices can be affected by hair and scalp disease, hair type, and social determinants of health.

Expected outcomes

Immediate desired changes in cosmetic appearance can be achieved with topical camouflaging agents, hair dyes, conditioning, volumizers, and heat styling tools in those with early AGA. Within days to weeks of initiating regular cleansing and shampooing of the scalp, a noticeable aesthetic difference in scale and scalp erythema may be noted in those with concomitant seborrheic dermatitis (level of evidence: 2b). Over years, combining medical hair growth treatment options with hair cosmetics, styling, and processing as part of a comprehensive plan can result in an improved appearance. As the hair grows over time, scalp and hair shaft health may improve, including increased shine, length, and strength, along with decreases in hair-shaft disease (e.g., bubble hair, trichorrhexis nodosa, trichoptilosis, trichoschisis). Without addressing the AGA disease process, the disease may continue to progress, and these techniques may slowly prove to be less useful. Patients may have the expectation that, with medical treatment, their hair will grow more rapidly, and results will be immediate. However, the rate of hair growth varies among individuals and can differ from scalp location and age (level of evidence: 2b) ( Pearl 5.2 ). Adjusting patient expectations with regard to expected results and timelines is fundamental to cosmetic hair counseling success. ^,