Incubatory environment of the scalp impacts pre‐emergent hair to affect post‐emergent hair cuticle integrity

Abstract

SummaryObjectives: To determine whether the oxidative stress transmitted to newly grown hair from an unhealthy scalp has physical consequences to the cuticular condition and function.Methods: A uniquely designed 24-week clinical study included 8 weeks of pretreatment with a cosmetic shampoo and 16 weeks of treatment with either a potentiated zinc pyrithione (ZPT) antidandruff shampoo or a placebo cosmetic shampoo.This clinical design allowed the growth and acquisition of hair samples under conditions of varying but known scalp health as a result of treating a dandruff/seborrheic dermatitis (D/SD) population. Two complementary methods were used to characterize the integrity of the cuticular surface. Hair surface hydrophobicity was assessed by quantifying water wetting force using a Wilhelmy balance method. Surface structure and porosity were assessed using dynamic vapor sorption (DVS) to gravimetrically quantify water sorption.Results: Chemical oxidative stress to pre-emergent hair has been shown to have negative consequences to hair surface structure. Compared to a placebo shampoo control, use of a potentiated ZPT shampoo improved scalp health and significantly improved the following attributes associated with healthy hair: hair surface hydrophobicity (surface energy) and cuticular moisture barrier effectiveness (dynamic vapor sorption).Conclusions: Pre-emergent hair can be negatively impacted by the oxidative stress that occurs with an unhealthy scalp, possibly due to metabolic activity of resident microbes. Manifestations of the oxidative stress include altered cuticle surface properties that are responsible for its protective function; these effects are similar in type to those observed by bleaching post-emergent hair. These alterations have the potential to make the hair, once emerged from the scalp, more susceptible to the cumulative physical and chemical insults responsible for hair feel and look, fiber integrity, and overall retention. K E Y W O R D Sdandruff, hair quality, HODE, oxidative stress, seborrheic dermatitis Retired (NR-F).

<p>Assessment of macrophage migration inhibitory factor in patients with verruca vulgaris</p>

“…On the other hand, El Hamd et al23 found that serum levels of MIF were significantly lower in patients with cutaneous warts compared to their healthy controls which could be explained by shift of MIF to the wart sites, a result which needs further research.…”

A comment on the science of hair aging

“…The protective benefits of the hair to the scalp, such as UVR screening, moisture retention, and mechanical shielding, are apparent, while the role of the scalp as an incubatory environment for the pre-emergent hair fiber is often disregarded. [41] However, there is a wealth of observational data on specific dermatological conditions of the scalp, such as dandruff and seborrheic dermatitis,[42434445464748] atopic dermatitis,[4449] and psoriasis,[50515253545556575859] providing the evidence for the role of the scalp condition in supporting the production of healthy hair. Again, oxidative stress is prevalent in all of these skin conditions,[60616263646566676869707172] just as in normal skin aging and related to the specific microbiome of the scalp and to the environmental exposures.…”

Scalp condition impacts hair growth and retention via oxidative stress

“…The protective benefits of the hair to the scalp, such as ultraviolet radiation (UVR) screening, moisture retention, and mechanical shielding, are obvious, while the role of the scalp as an incubatory environment for the preemergent hair fiber is often overlooked. [3]…”