Darier's disease exhibits a unique cutaneous microbial dysbiosis associated with inflammation and body malodour

Darier disease: Current insights and challenges in pathogenesis and management

Darier disease is a rare autosomal dominant genodermatosis caused by mutations in the ATP2A2 gene encoding for sarcoendoplasmic reticulum Ca2+ ATPase isoform 2. The skin disease is characterized by a chronic relapsing course with recurrent reddish-brown keratotic papules and plaques located mainly in seborrhoeic areas. Due to chronic inflammation and epidermal barrier defects of the skin, patients often develop severe bacterial and viral superinfections. Therapeutic options are limited, mainly symptomatic and in most cases unsatisfactory in the long term. Patients are advised to avoid aggravating factors such as high temperature, high humidity, UV radiation and mechanical irritation. To prevent superinfection, antiseptics and periodic use of topical corticosteroids are fundamental in treatment. In case of bacterial and viral superinfection, systemic anti-infective therapy is often necessary. Currently, the most effective treatment option for extensive and persistent skin lesions is systemic retinoids, which are thought to mainly target the epidermal compartment (e.g. by reducing hyperkeratosis). One hallmark of Darier disease patients is chronic skin inflammation. We and others have previously reported Th17 cells in the dermal infiltrate of inflamed Darier disease skin. Counteracting inflammation by blocking the IL-23/IL-17 axis improved skin manifestations in a small cohort of previously therapy-resistant patients over 1 year. Furthermore, several other topical treatment options for mild disease as well as various ablative therapies and surgical excision have been proposed to be effective in some patients with hypertrophic skin lesions. This article aims to outline the pathogenesis, clinical features, diagnosis/differential diagnosis and available treatment modalities of Darier disease.

Skin microbiome dynamics in patients with polymorphic light eruption in response to ultraviolet radiation

BACKGROUND

Polymorphic light eruption (PLE) is the most frequent photodermatosis in Europe, with an estimated prevalence of 10-20%, particularly in temperate climates. Itching or burning lesions appear only in sun-exposed areas, predominantly on the chest, arms and forearms, within a few hours following exposure. The cause of the disease remains unknown, yet studies have suggested that microbial elements in the skin may play a role in its pathogenesis.

OBJECTIVES

To investigate the skin microbiome of a cohort of patients with PLE upon exposure to ultraviolet radiation (UVR), to assess its role in the onset of PLE lesions.

METHODS

Forty-one skin swabs were collected from 11 patients with PLE at baseline and after 3 days of exposure to UVR, and from healthy control participants. The collected swabs were analysed for their microbial composition using a 16S amplicon sequencing approach.

RESULTS

PLE skin showed a dysbalanced microbiome at baseline, with significantly reduced microbial diversity and noticeable colonization by bacterial pathogens, including Staphylococcus aureus. Upon UVR exposure, the PLE microbiome exhibited further loss of diversity and a reduction in beneficial skin commensals. In line with this, we found that UVR exerted strong antimicrobial effects in vitro against representative skin residents.

CONCLUSIONS

UVR can lead to profound changes in the skin microbiome, allowing the proliferation of dysbiotic members that can release a variety of elements able to trigger PLE lesions. This is the first study to investigate the cutaneous microbiome changes in patients with PLE upon UVR exposure, offering new insights into disease pathogenesis that has so far been unexplored.

Pruritus and Neuropsychiatric Symptoms Among Patients with Darier Disease-An Overlooked and Interconnected Challenge

(1) Background: Darier disease (DD) is a rare autosomal dominant disorder caused by mutations in ATP2A2, a gene that encodes the sarco(endo)plasmic reticulum calcium-ATPase 2 enzyme, which disrupts calcium homeostasis in keratinocytes. Pruritus, a frequently overlooked symptom in DD, can lead to physical and emotional complications, especially in patients with DD who are genetically predisposed to psychiatric comorbidities. (2) Methods: This study aimed to analyze pruritus and other related symptoms in patients with DD and explore their correlation with neuropsychiatric conditions, psychological challenges, disease severity, and body surface area (BSA) involvement through a retrospective review of a tertiary center. (3) Results: Data from 76 patients (equal gender distribution, mean age 44 years) revealed a prevalence of pruritus of 90.8%, surpassing symptoms such as pain (34.3%) and malodor (43.4%). Burning sensations due to DD lesions were significantly correlated with the diagnosis of comorbid neuropsychiatric conditions (p = 0.047) and psychiatric medication use (p = 0.019). While pruritus correlated with disease severity and %BSA involvement, the findings were not statistically significant. Patients reporting pruritus had a significantly higher Dermatology Life Quality Index symptom score (2.4 ± 1.0), which is defined as the presence of itch, soreness, pain, or stinging, than those who did not (1.5 ± 0.6), indicating accurate symptom reporting. (4) Conclusions: In conclusion, a striking majority of patients with DD experience pruritus, with higher prevalence among those with neuropsychiatric challenges, severe Darier disease, and greater %BSA skin involvement. Clinicians should recognize pruritus as a key therapeutic target and adopt comprehensive treatment approaches that both address the neuropsychiatric comorbidities and the added psychological burden of pruritus in patients with DD.

Pumping the Breaks on Acantholytic Skin Disorders: Targeting Calcium Pumps, Desmosomes, and Downstream Signaling in Darier, Hailey-Hailey, and Grover Disease

Acantholytic skin disorders, by definition, compromise intercellular adhesion between epidermal keratinocytes. The root cause of blistering in these diseases traces back to direct disruption of adhesive cell-cell junctions, exemplified by autoantibody-mediated attack on desmosomes in pemphigus. However, genetic acantholytic disorders originate from more indirect mechanisms. Darier disease and Hailey-Hailey disease arise from mutations in the endoplasmic reticulum calcium pump, SERCA2, and the Golgi calcium/manganese pump, SPCA1, respectively. Though the disease-causing mutations have been known for nearly 25 years, the mechanistic linkage between dysregulation of intracellular ion stores and weakening of cell-cell junctions at the plasma membrane remains puzzling. The molecular underpinnings of a related idiopathic disorder, Grover disease, are even less understood. Due to an incomplete understanding of acantholytic pathology at the molecular level, these disorders lack proven, targeted treatment options, leaving patients with the significant physical and psychological burdens of chronic skin blistering, infections, and pain. This article aims to review what is known at the molecular, cellular, and clinical levels regarding these under-studied disorders and to highlight knowledge gaps and promising ongoing research. Armed with this knowledge, our goal is to aid investigators in defining essential questions about disease pathogenesis and to accelerate progress toward novel therapeutic strategies.

Microbial imbalance in Darier disease: Dominance of various staphylococcal species and absence of Cutibacteria

Darier disease (DD) is a rare autosomal dominant genodermatosis characterized by erythematous papules and plaques mainly involving sebaceous areas, such as the face, chest and back. Skin microbiome plays an essential role in maintaining skin homeostasis. A disturbed skin microbiome may contribute to the exacerbation of DD. We investigated the bacterial composition of two predilectional sites in DD patients and healthy individuals. We also measured the microbiome composition of deeper skin layers, where diversity was significantly reduced compared to the superficial layer of the skin from the same area. The microbiome of DD patients at lesional sites differed from that of non-lesional skin areas; moreover, non-lesional sites were different from those of the controls. Lesional areas were dominated by Staphylococcus species, such as S. aureus, S. epidermidis, S. hominis, S. sciuri, and S. equorum. However, levels of Cutibacterium acnes (formerly Propionibacterium acnes) and C. acnes subspecies defendens were significantly lower in lesional sites than in non-lesional sites. A significant decrease was measured in the levels of these two bacteria between non-lesional and control samples. Our findings may indicate that alterations in the skin microbiome could contribute to the inflammation of skin lesions in DD.

Dantrolene corrects cellular disease features of Darier disease and may be a novel treatment

Darier disease (DD) is a rare severe acantholytic skin disease caused by mutations in the ATP2A2 gene that encodes for the sarco/endoplasmic reticulum calcium ATPase isoform 2 (SERCA2). SERCA2 maintains endoplasmic reticulum calcium homeostasis by pumping calcium into the ER, critical for regulating cellular calcium dynamics and cellular function. To date, there is no treatment that specifically targets the disease mechanisms in DD. Dantrolene sodium (Dl) is a ryanodine receptor antagonist that inhibits calcium release from ER to increase ER calcium levels and is currently used for non-dermatological indications. In this study, we first identified dysregulated genes and molecular pathways in DD patient skin, demonstrating downregulation of cell adhesion and calcium homeostasis pathways, as well as upregulation of ER stress and apoptosis. We then show in various in vitro models of DD and SERCA2 inhibition that Dl aided in the retention of ER calcium and promoted cell adhesion. In addition, Dl treatment reduced ER stress and suppressed apoptosis. Our findings suggest that Dl specifically targets pathogenic mechanisms of DD and may be a potential treatment.

Favorable Response to Type 2 Inhibitors in Patients With Darier Disease

This case report describes 2 female patients who both presented with severe and recalcitrant Darier disease who were treated with type 2 inflammation inhibitors.

Unmet Needs in Darier's Disease from a Patient's Perspective: Lessons Learnt from the German Registry

The MDHHgermany registry was initiated to characterize the "real-life" situation of affected individuals with Darier's disease (DD; Morbus Darier, MD) and Hailey-Hailey disease (HH), including their treatment and healthcare. To gain deeper insights into medical care of patients with DD, various aspects such as demographics, subjective symptoms, patient satisfaction with medical care, past and current therapies were explored. Patients with diagnosed DD were included. Subjective symptoms such as itch, pain and burning sensation were assessed. Individual therapy goals were recorded and patients assessed previous/current therapies along with satisfaction of medical care and treatment. A total of 55 patients were recruited; 47 patients were eligible for the analysis. Pruritus was rated the most bothersome symptom. Some 42.6% had not received systemic treatment so far or systemic therapies were rated ineffective (32.6%). Most commonly oral retinoids were prescribed, followed by corticosteroids. Patient satisfaction with medical care and treatment proved to be mediocre. This "real-life" data show an alarming unmet need regarding patients' satisfaction with medical care and treatment, evidenced by the reported lack of disease control. Further studies and interventions are needed to improve the spectrum of available therapies. MDHHgermany provides a foundational platform for future clinical trials, epidemiological studies, and pathophysiological analyses.

Patients' perspective, quality of life and treatment goals in Hailey-Hailey disease: Lessons learned from the German National Registry

BACKGROUND

Hailey-Hailey disease (HHD) remains a difficult-to-treat dermatosis and little is known about the patient's perception of the disease activity, the treatment success and its impact on quality-of-life (QoL).

OBJECTIVE

To obtain better understanding of HHD patients' needs regarding their medical condition, financial burden, QoL, subjective well-being and treatment thereof as well as satisfaction to evaluate common treatments' 'real-life' relevance.

METHODS

With initiation of the national registry for Darier's disease (DD; Morbus Darier, MD) and Hailey-Hailey disease (HH) MDHHgermany, patients with HHD diagnosis were included starting June 2020. To assess subjective symptoms, patients filled out questionnaires such as the DLQI (dermatological life quality index), numeric rating scale (NRS) for itch, pain and burning sensation, as well as the SWLS (satisfaction with life scale) questionnaire to quantify overall satisfaction in life. Additionally, data on therapies were collected along with the patients' satisfaction of those and their medical care. Furthermore, patients assessed financial aspects and work ability.

RESULTS

One hundred and two patients were recruited from dermatology clinics, office-based dermatologists and self-help platforms across Germany between June 2020 and February 2023, 90 were eligible and analysed (mean: 49.91 years, 73.33% females, 26.67% males). 39.77% stated according to the DLQI their life is severely/very severely affected. Satisfaction with life was mediocre. Burning sensation was most pronounced among subjective symptoms (NRS 5.85 ± 2.80). Systemic treatments were rated as ineffective according to 56.92%, 25.56% had never received one. Most prescribed systemic treatments were corticosteroids (73.8%), followed by low-dose naltrexone (LDN) (26.2%), retinoids (15.4%) and antibiotics (13.8%). Satisfaction with medical care was generally low.

CONCLUSION

Our 'real-life' data state a major disease burden and impact on the QoL for affected individuals, as well as limited disease control due to inadequate therapies. MDHHgermany can provide insights into improvement of healthcare support with this debilitating disease and improve QoL. In the long term, it aims to provide basis for further clinical trials, epidemiological studies and immunological investigations.