Role of scalp health in achieving optimal hair growth and retention. (12th October 2021)

• Record Type: Journal Article
• Authors: Tosti, Antonella; Schwartz, James R.
• Is Part Of: International journal of cosmetic science. Volume 43(2021)Supplement 1
• Page Start: S1
• Page End: S8
• Publication Date: 2021-10-12
• Subjects: growth -- hair -- oxidative stress -- retention -- scalp; Cosmetics -- Periodicals; 668.5505
• DOI: 10.1111/ics.12708
• Languages: English
• ISSNs: 0142-5463

Abstract

Abstract: We have conducted a thorough review of the literature to assess the evidence for supporting a cause‐and‐effect linkage between scalp condition and resultant hair condition. Over 20 epidemiological studies have been published covering a wide range of abnormal scalp conditions in which consequent impacts to the hair have been documented. A treatment study was conducted to demonstrate not only that impaired scalp condition led to impaired hair quality but that the impacts to hair are reversible upon normalization of the scalp condition. A proposed explanation involves the impact of scalp oxidative stress, which is part of the etiology of these scalp conditions as well as normal aging, in interfering with the normal keratinization of the pre‐emergent hair cuticle. This perturbed cuticle impedes normal fiber anchorage and emerges more brittle and fragile than normal cuticle leading to accelerated physical degradation, mirroring the effects of chronological aging of the hair fiber. The consequences of the rapid cuticle degradation result in hair that is more vulnerable to mechanical insults and compromised overall quality. Abstract : This manuscript is one component of a five‐part Supplement establishing both mechanisms and treatments for inhibiting non‐genetic forms of premature hair loss. In this case, we review the published data supporting a cause‐and‐effect relationship between scalp condition and the normal growth and retention of scalp hair. Over the last 50 years, there is a wide range of mostly epidemiological studies on common scalp conditions indicating the perturbed scalp condition resulted in either or both altered hair surface properties and premature loss. A seminal treatment study confirmed the cause‐and‐effect relationship by following the impact to hair properties as scalp condition improved. Taken together, this leads to the very important insight that achieving normal hair growth and retention is dependent upon having a foundational scalp skin condition that is not stressed. The nature of the scalp stresses may be tied specifically to the many sources of oxidative stress. This review brings together a wide range of data to assemble a picture that that the conditions of the scalp impact the pre‐emergent hair fiber in a way that is propagated to the post‐emergent fiber impacting both overall hair condition and its retention. This review reinforces that good scalp is required to maximize benefits to the growing hair. Résumé: Nous avons mené un examen approfondi de la littérature médicale pour évaluer les preuves étayant un lien de cause à effet entre l'état du cuir chevelu et celui des cheveux. Plus de 20 études épidémiologiques ont été publiées, couvrant un large éventail d'affections du cuir chevelu pour lesquelles des impacts conséquents sur les cheveux ont été documentés. Une étude de traitement a été menée pour démontrer non seulement qu'une altération du cuir chevelu entraînait une altération de la qualité des cheveux, mais aussi que les impacts sur les cheveux étaient réversibles après normalisation de l'état du cuir chevelu. Une explication proposée inclut l'impact du stress oxydatif sur le cuir chevelu, qui fait partie de l'étiologie de ces affections du cuir chevelu ainsi que du vieillissement normal, en interférant avec la kératinisation normale de la cuticule du cheveu à son point d'émergence. Cette cuticule perturbée gêne l'ancrage normal des fibres et fait émerger des cuticules plus fragiles et friables que la normale, entraînant une dégradation physique accélérée, reflet des effets du vieillissement chronologique des fibres capillaires. La dégradation rapide de la cuticule rend les cheveux plus vulnérables aux agressions mécaniques et compromet leur qualité globale.