Alopecia in epidermolysis bullosa

Folliculitis decalvans and dystrophic epidermolysis bullosa: a significant association

This work reports 30 cases of folliculitis decalvans (FD) in patients with dystrophic epidermolysis bullosa (DEB) among a cohort of 125 DEB patients seen between 2010 and 2021 in 2 French expert centers for the management of inherited epidermolysis bullosa. Such an association between two rare diseases cannot be fortuitous and implies a physiopathological link that we discuss in this paper. This association is a new significant fact to add to the reflexion on FD causes, suggesting that skin abnormality of DEB could act as a factor of a specific skin barrier alteration which could favor FD. Scarring alopecia with tufted folliculitis and pustules on inflamed skin at the vertex of a woman with dominant dystrophic epidermolysis bullosa.

Current topics in Epidermolysis bullosa: Pathophysiology and therapeutic challenges

Epidermolysis bullosa (EB) is a group of inherited skin and mucosal fragility disorders resulting from mutations in genes encoding basement membrane zone (BMZ) components or proteins that maintain the integrity of BMZ and adjacent keratinocytes. More than 30 years have passed since the first causative gene for EB was identified, and over 40 genes are now known to be responsible for the protean collection of mechanobullous diseases included under the umbrella term of EB. Through the elucidation of disease mechanisms using human skin samples, animal models, and cultured cells, we have now reached the stage of developing more effective therapeutics for EB. This review will initially focus on what is known about blister wound healing in EB, since recent and emerging basic science data are very relevant to clinical translation and therapeutic strategies for patients. We then place these studies in the context of the latest information on gene therapy, read-through therapy, and cell therapy that provide optimism for improved clinical management of people living with EB.

Hair follicle stem cell progeny heal blisters while pausing skin development

Injury in adult tissue generally reactivates developmental programs to foster regeneration, but it is not known whether this paradigm applies to growing tissue. Here, by employing blisters, we show that epidermal wounds heal at the expense of skin development. The regenerated epidermis suppresses the expression of tissue morphogenesis genes accompanied by delayed hair follicle (HF) growth. Lineage tracing experiments, cell proliferation dynamics, and mathematical modeling reveal that the progeny of HF junctional zone stem cells, which undergo a morphological transformation, repair the blisters while not promoting HF development. In contrast, the contribution of interfollicular stem cell progeny to blister healing is small. These findings demonstrate that HF development can be sacrificed for the sake of epidermal wound regeneration. Our study elucidates the key cellular mechanism of wound healing in skin blistering diseases.

Alopecia as a systemic disease

Alopecia is a skin condition of great social and psychologic impact. Primary alopecia originates from the hair follicles and usually does not have systemic manifestations; however, secondary alopecia can affect the hair follicles in the setting of systemic diseases, medications, and external trauma. Connective tissue diseases, granulomatous diseases, bullous diseases, infections, and tumors are some of the systemic diseases that will be covered in this review. Trichoscopy is a useful noninvasive tool that can help with the diagnosis in the office and can guide the selection of the optimal site for the scalp biopsy. Histopathology is the ultimate tool for the diagnosis in most cases of secondary alopecia and can be performed on vertical and horizontal sections. In most cases, treating the underlying condition is the single most important strategy, but topical treatments for the alopecia are also applied.

Alopecia in Autoimmune Blistering Diseases: A Systematic Review of Pathogenesis and Clinical Features of Disease

Background

Autoimmune blistering diseases (AIBD) are characterised by the body's production of autoantibodies against structural proteins in the epidermis and/or the basement membrane on cutaneous and mucosal surfaces. Alopecia is a complication of AIBD that has generally been overlooked in patients with severe blistering diseases because it is regarded as a cosmetic issue. Yet recent research into quality of life tools has found that stigmatisation by appearance plays a significant role in blistering diseases.

Aim

To review the current literature detailing the pathogenesis and clinical presentations of alopecia in AIBD patients.

Method

We searched Medline, PubMed and EMBASE electronic databases up to September 2018, for empirical human and animal studies.

Results

Only 36 human studies including 223 patients (190 pemphigus, 25 pemphigoid, 5 epidermolysis bullosa acquisita, 2 dermatitis herpetiformis and 1 linear IgA disease) detailed demographic and clinical manifestations of alopecia. A range of hair evaluation methods was demonstrated to reach alopecia diagnosis. Furthermore, with no universal validated scoring system for alopecia severity, alopecia patterns have been summarised.

Conclusion

Previous randomised trials have not highlighted alopecia as an important outcome of AIBD, so epidemiological evaluation of the available literature has been helpful in summarising trends between existing studies and demonstrating inconsistencies.

Pathogenesis and clinical features of alopecia in epidermolysis bullosa: A systematic review

BACKGROUND

Epidermolysis bullosa (EB) is a group of rare genetic skin diseases characterized by the gene mutations encoding adhesion proteins within the skin. These adhesion proteins are also present in normal hair follicles. Anecdotally, there have been reports of scalp alopecia as a complication of EB and there are scattered cases in the literature, but alopecia has generally been overlooked in severe blistering diseases because it is regarded as a cosmetic issue. Therefore, there is no consensus about the natural history and clinical manifestations of alopecia in EB to allow potential intervention.

OBJECTIVES

To review the current literature detailing the pathogenesis and clinical presentations of alopecia in EB patients.

METHODS

Relevant human studies were searched in Medline, PubMed, and EMBASE electronic databases up to October 2018.

RESULTS

Only 15 reports detailed 29 EB patients with demographic and clinical manifestations of alopecia. Vertical biopsy sections were the most common method of alopecia diagnosis, and the most common pattern was patchy scalp alopecia (45%) followed by diffuse alopecia (41%). The most robust finding was nonspecific scarring alopecia in all dystrophic EB (DEB) patients and nonspecific nonscarring alopecia in most patients with EB simplex (EBS).

CONCLUSIONS

Hair abnormalities observed in EB are of variable severity despite there being no universal validated alopecia scoring system, with alopecia occurring secondary to blistering, or in areas prone to trauma.

The integrin adhesome: from genes and proteins to human disease

The adhesive interactions of cells with their environment through the integrin family of transmembrane receptors have key roles in regulating multiple aspects of cellular physiology, including cell proliferation, viability, differentiation and migration. Consequently, failure to establish functional cell adhesions, and thus the assembly of associated cytoplasmic scaffolding and signalling networks, can have severe pathological effects. The roles of specific constituents of integrin-mediated adhesions, which are collectively known as the 'integrin adhesome', in diverse pathological states are becoming clear. Indeed, the prominence of mutations in specific adhesome molecules in various human diseases is now appreciated, and experimental as well as in silico approaches provide insights into the molecular mechanisms underlying these pathological conditions.

Inherited epidermolysis bullosa: clinical and therapeutic aspects

Inherited epidermolysis bullosa (EB) is a heterogeneous group of genetic disorders that present with skin and, in some cases, mucosal fragility, predisposing patients to the development of blisters and/or erosions after minimal trauma or friction. Children with a recurrent history of these kinds of lesions or neonates that present them in the absence of another reasonable explanation should be investigated. Diagnosis must be based on clinical and histopathological findings. To date, management of inherited EB basically consists in avoiding traumas that trigger lesions, as well as preventing infection and facilitating healing of the wounds with the systematic use of bandages.

Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period

OBJECTIVE

To evaluate morphometric-stereological changes in the epididymal caput, sperm quality, and fertility parameters in rats treated with finasteride and after a 30-day post-treatment recovery period.

DESIGN

Experimental study in a research laboratory.

SETTING

Reproductive biology research laboratory.

ANIMAL(S)

Male and female Sprague Dawley rats.

INTERVENTION(S)

Treatment with finasteride (5 mg/kg/day) for 56 days followed by 30 days without treatment.

MAIN OUTCOME MEASURE(S)

Serum hormone analyses, morphometric-stereological and ultrastructural evaluation of the epididymal caput, sperm transit time, natural mating, in utero insemination, sperm membrane integrity, and fertility parameters.

RESULT(S)

Serum dihydrotestosterone levels in the finasteride group decreased by ~40% compared with that of control rats. Ultrastructural analysis revealed significant reductions in several morphometric-stereological parameters of the epididymal caput. All parameters recovered significantly in the post-treatment period. There was no alteration in daily sperm production in the finasteride group. However, significant reductions in sperm transit time, motility, sperm membrane integrity, and fertility parameters were observed in rats treated with finasteride.

CONCLUSION(S)

Treatment with finasteride caused morphometric-stereological and functional changes in the epididymis and in sperm function that led to a reduction in fertility parameters. A 30-day post-treatment recovery period was insufficient to restore normal sperm motility, sperm transit time, and some fertility parameters.