Mosaic hair color changes in alopecia areata

White hair in alopecia areata: Clinical forms and proposed physiopathologic mechanisms

Alopecia areata (AA) is a common form of nonscarring hair loss. It is believed to be a consequence of an immune-mediated stimulus, probably involving autoreactive T cells against antigens present in the hair follicle. The exact antigen is still unknown; however, some authors have proposed that melanogenesis-associated molecules might trigger autoimmunity. Although transient white hair regrowth is a common and well-known situation in AA, there are other types of white hair phenomena in this context, including permanent white hair regrowth, sparing of white hair in a patchy pattern, or sparing in a diffuse pattern, giving the appearance of the so-called overnight graying phenomena or canitis subita. In this review, we aim to describe the different clinical aspects of white hair in AA, as well as the proposed pathophysiologic mechanisms involved in this phenomena.

Hair repigmentation and regrowth in a dupilumab-treated paediatric patient with alopecia areata and atopic dermatitis: a case report

Alopecia areata (AA) is a chronic inflammatory disease mainly involving Th1 immunoreaction, but Th2 is also involved. A 9-year-old girl presented to our clinic with severe alopecia for 2 months and pruritus-related rashes for 8 years. She was diagnosed with AA and atopic dermatitis (AD), and the Severity of Alopecia Tool (SALT) score was 98. She used a 0.05% halometasone cream (occlusive dressing) topically applied overnight (6 days weekly) for 10 months. After 2 months of treatment, she had regrowth of both black and white hair. However, relapse occurred and she gradually lost all black terminal hair, but white terminal hair remained, with a SALT score of 70. Continuous topical occlusion resulted in white hair regrowth with a SALT score of 20 at the end of month 10. Dupilumab was initially prescribed as a 600-mg subcutaneous injection and maintained at 300 mg every 4 weeks thereafter. Hair repigmentation (10% of whole hair density) started, with black hair shaft appearing at the proximal end in parietal-occipital and occipital areas after three injections at week 12 of dupilumab therapy, with a SALT score of 10. After seven injections at week 28, the percentage of black hair shaft reached up to 90, and she regained her black hair and the pigmented section of hair shaft continued to grow longer at the rate of normal hair growth. Nevertheless, 4 months after termination of dupilumab therapy, the black terminal hair began to fall off, and white vellus hair gradually regrew on the scalp, with a SALT score of 80. Dupilumab induces hair regrowth and repigmentation of white terminal hair without disturbing the anagen phase of hair follicles. Therefore, melanocytes in AA may be a potential target of Th2-related factors. Persistent regrowth of white hair may be used as a signal of Th2 dominance in AA management.

Hair Follicle Melanocytes Initiate Autoimmunity in Alopecia Areata: a Trigger Point

Alopecia areata (AA) is characterized by common non-scarring alopecia due to autoimmune disorders. To date, the specific pathogenesis underlying AA remains unknown. Thus, AA treatment in the dermatological clinic is still a challenge. Numerous clinical observations and experimental studies have established that melanocytes may be the trigger point that causes hair follicles to be attacked by the immune system. A possible mechanism is that the impaired melanocytes, under oxidative stress, cannot be repaired in time and causes apoptosis. Melanocyte-associated autoantigens are released and presented, inducing CD8⁺ T cell attacks. Thereafter, amplification of the immune responses further spreads to the entire hair follicle (HF). The immune privilege of HF subsequently collapses, leading to AA. Herein, we present a narrative review on the roles of melanocytes in AA pathogenesis, aiming to provide a better understanding of this disease from the melanocyte's perspective.

Quantitative mapping of human hair greying and reversal in relation to life stress

Background:

Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.

Methods:

Here, we develop an approach to profile hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions.

Results:

Using this method, we show white/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, thereby quantitatively defining the reversibility of greying in humans. Molecularly, grey hairs upregulate proteins related to energy metabolism, mitochondria, and antioxidant defenses. Combining HPP profiling and proteomics on single hairs, we also report hair greying and reversal that can occur in parallel with psychological stressors. To generalize these observations, we develop a computational simulation, which suggests a threshold-based mechanism for the temporary reversibility of greying.

Conclusions:

Overall, this new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology.

Funding:

This work was supported by the Wharton Fund and NIH grants GM119793, MH119336, and AG066828 (MP).

Hair greying is a visible sign of aging that affects everyone. The loss of hair color is due to the loss of melanin, a pigment found in the skin, eyes and hair. Research in mice suggests stress may accelerate hair greying, but there is no definitive research on this in humans. This is because there are no research tools to precisely map stress and hair color over time. But, just like tree rings hold information about past decades, and rocks hold information about past centuries, hairs hold information about past months and years.

Hair growth is an active process that happens under the skin inside hair follicles. It demands lots of energy, supplied by structures inside cells called mitochondria. While hairs are growing, cells receive chemical and electrical signals from inside the body, including stress hormones. It is possible that these exposures change proteins and other molecules laid down in the growing hair shaft. As the hair grows out of the scalp, it hardens, preserving these molecules into a stable form. This preservation is visible as patterns of pigmentation. Examining single-hairs and matching the patterns to life events could allow researchers to look back in time through a person’s biological history.

Rosenberg et al. report a new way to digitize and measure small changes in color along single human hairs. This method revealed that some white hairs naturally regain their color, something that had not been reported in a cohort of healthy individuals before. Aligning the hair pigmentation patterns with recent reports of stress in the hair donors’ lives showed striking associations. When one donor reported an increase in stress, a hair lost its pigment. When the donor reported a reduction in stress, the same hair regained its pigment. Rosenberg et al. mapped hundreds of proteins inside the hairs to show that white hairs contained more proteins linked to mitochondria and energy use. This suggests that metabolism and mitochondria may play a role in hair greying. To explore these observations in more detail Rosenberg et al. developed a mathematical model that simulates the greying of a whole head of hair over a lifetime, an experiment impossible to do with living people. The model suggested that there might be a threshold for temporary greying; if hairs are about to go grey anyway, a stressful event might trigger that change earlier. And when the stressful event ends, if a hair is just above the threshold, then it could revert back to dark.

The new method for measuring small changes in hair coloring opens up the possibility of using hair pigmentation patterns like tree rings. This could track the influence of past life events on human biology. In the future, monitoring hair pigmentation patterns could provide a way to trace the effectiveness of treatments aimed at reducing stress or slowing the aging process. Understanding how ‘old’ white hairs regain their ‘young’ pigmented state could also reveal new information about the malleability of human aging more generally.

Alopecia Areata: a Comprehensive Review of Pathogenesis and Management

Alopecia areata is a common hair loss condition that is characterized by acute onset of non-scarring hair loss in usually sharply defined areas ranging from small patches to extensive or less frequently diffuse involvement. Depending on its acuity and extent, hair loss is an important cause of anxiety and disability. The current understanding is that the condition represents an organ-specific autoimmune disease of the hair follicle with a genetic background. Genome-wide association studies provide evidence for the involvement of both innate and acquired immunity in the pathogenesis, and mechanistic studies in mouse models of alopecia areata have specifically implicated an IFN-γ-driven immune response, including IFNγ, IFNγ-induced chemokines and cytotoxic CD8 T cells as the main drivers of disease pathogenesis. A meta-analysis of published trials on treatment of alopecia areata states that only few treatments have been well evaluated in randomized trials. Nevertheless, depending on patient age, affected surface area and disease duration, an empiric treatment algorithm can be designed with corticosteroids and topical immunotherapy remaining the mainstay of therapy. The obviously limited success of evidence-based therapies points to a more important complexity of hair loss. At the same time, the complexity of pathogenesis offers opportunities for the development of novel targeted therapies. New treatment opportunities based on the results of genome-wide association studies that implicate T cell and natural killer cell activation pathways are paving the way to new approaches in future clinical trials. Currently, there are ongoing studies with the CTLA4-Ig fusion protein abatacept, anti-IL15Rβ monoclonal antibodies and the Janus kinase inhibitors tofacitinib, ruxolitinib and baricitinib. Ultimately, the options available for adapting to the disease rather than treating it in an effort to cure may also be taken into consideration in selected cases of long-standing or recurrent small spot disease.

Etiopathogenesis of alopecia areata: Why do our patients get it?

Alopecia areata (AA) is a nonscarring, inflammatory skin disease that results in patchy hair loss. AA is unpredictable in its onset, severity, and duration making it potentially very stressful for affected individuals. Currently, the treatment options for AA are limited and the efficacy of these treatments varies from patient to patient. The exact etiology of AA is unknown. This article provides some insights into the etiopathogenesis of AA and why some people develop it. The current knowledge on the pathogenesis of AA is summarized and some of the recent hypotheses and studies on AA are presented to allow for a fuller understanding of the possible biological mechanisms of AA.

Migratory poliosis: A forme fruste of alopecia areata?

We describe a 19-year-old African-American man with a 14-year history of migratory poliosis. We suggest that this phenomenon may represent a forme fruste of alopecia areata.