Clinical and histopathological characteristics in patients with scarring folliculitis type of acne inversa

Hidradenitis suppurativa: Detangling phenotypes and identifying common denominators

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with a severe impact on patients' quality of life through its recurrent and painful nature, as well as its comorbidity burden. The shift in the pathogenic paradigm from a condition of the apocrine glands to an autoinflammatory disease associated with follicular destruction has rendered its understanding difficult, as there are still large gaps in pinpointing the underlying mechanisms, which cannot currently explain the existing clinical variation and as a result, translate into suboptimal therapy. Multifactorial involvement is hypothesized, with an implication of genetic mutations, microbiome dysbiosis, cytokine upregulation and environmental factors. Clinical observation is fundamental for diagnosis, however, the marked heterogeneity in presentation leads to delays in detection and challenges in treatment selection, showcasing clear limits in defining the link between genetic aspects of HS, the role of epigenetic factors and its pathogenic pathways. There have been attempts to formulate phenotypes that could aid in prognostication and management, however, current classification schemata show significant overlap and no validation through longitudinal studies. In this context, nomenclature poses a great challenge due to the lack of global agreement in the definition of lesions, which should be addressed by future research to enable simplified recognition and allow for more precise severity scoring. This could be complemented by the addition of extra dermatologic findings or paraclinical assessment in constructing phenotypes. The development of valid, predictive and reliable classifications of HS may lead to an improvement in comprehending its pathophysiology, favouring a more personalized approach in management. This could be achieved through consensus in the characterization of clinical features and data gathering, as well as validation attempts for described phenotypes. Ultimately, the genotype-endotype-phenotype correlation in HS requires targeted, systematic inquiries and should be addressed more largely to broaden the perspective on this debilitating entity.

Drug Survival of Oral Retinoids in Hidradenitis Suppurativa: A Real-Life Cohort Study

INTRODUCTION

Cohort studies on the use of retinoids for hidradenitis suppurativa (HS) have yielded contradicting results. As the clinical presentation of HS is heterogeneous, with different predilection sites and hallmark features, it can be hypothesized that HS phenotypes are associated with the effectiveness of specific retinoid treatments.

OBJECTIVES

The aim of this study was to evaluate the drug survival of oral retinoids in the treatment of HS and to establish predictors for longer treatment duration.

METHODS

A retrospective, dual-center study was conducted in the Netherlands in adult HS patients treated with oral retinoids between 2011 and 2021. Drug survival analyses were performed through Kaplan-Meier survival curves. Additionally, Cox regression models were used to determine predictors for a longer drug survival.

RESULTS

In total, 102 patients were included. Overall drug survival of (low-dose) isotretinoin (n = 66) at 12 and 24 months was 44.2% and 15.5%, respectively. Termination of treatment was mostly due to ineffectiveness (26%). Presence of widespread comedones (p = 0.03) and the use of concomitant systemic medication (p = 0.04) were associated with a prolonged treatment duration. For acitretin (n = 36), the overall drug survival was 42.0% at 12 months and 37.4% at 24 months, and was also predominantly determined by ineffectiveness (28%). Interestingly, the scarring folliculitis phenotype (p < 0.05) was associated with prolonged drug survival time for acitretin treatment relative to the regular phenotype.

CONCLUSION

Comparable drug survival rates at 12 months for isotretinoin and acitretin were found. HS patients with widespread comedones and the scarring folliculitis phenotype could benefit from treatment with isotretinoin or acitretin, respectively.

Effects of NCSTN Mutation on Hair Follicle Components in Mice

BACKGROUND AND OBJECTIVES

Hidradenitis suppurativa (HS)/acne inversa is an intractable skin disease that is characterized by destructive lesions - primarily on the flexural areas. Although its etiology is unknown, genetics is considered to be a factor of its pathology - mutations in γ-secretase genes have been identified in certain familial HS patients, and follicular occlusion is widely accepted as the primary cause of HS. But, no relationship between these mutations and the components of hair follicles has been reported. Thus, we examined changes in these components in mice with a mutation in NCSTN (a γ-secretase gene).

METHODS

We generated C57BL/6 mice with an NCSTN mutation and examined their expression of hair cortex cytokeratin and trichohyalin by Western blot and immunohistochemistry, in addition to nicastrin, the product of NCSTN, and NICD compared with wild-type mice. The structure of hair follicles was analyzed by hematoxylin-eosin staining and transmission electron microscopy.

RESULTS

In mice with an NCSTN mutation, HS-like skin lesions appeared after age 6 months, the pathological manifestations of which were consistent with the features of human HS. The structure of hair follicles was abnormal in mice with an NCSTN mutation versus wild-type mice, and hair cortex cytokeratin, trichohyalin, nicastrin, and NICD were downregulated in these mice.

CONCLUSIONS

This NCSTN mutant mouse model could be an improved model to study early lesion development aspects of human HS pathogenesis and could perhaps be a better alternative for evaluating early-acting and preventive therapeutics for HS experimentally before clinical trials in HS patients. NCSTN mutations disrupt the development of hair follicles, leading to abnormal hair follicle structures, perhaps resulting in the onset of HS.

Botulinum toxin type A for the management of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory skin disease that centers around the hair follicle and occurs as a result of follicular occlusion. HS primarily presents as painful, inflamed lesions that begin during puberty and occur most commonly in areas with numerous apocrine glands. The etiology and pathogenesis of HS involve internal and external factors, including genetic susceptibility, inflammation and immunity, microorganisms, obesity, and smoking. Management of HS is difficult, and the current aim of treatment is to control the frequency and duration of disease flare-ups and improve the quality of life. Medical treatments include antibiotics, retinoids, biologics, immunosuppressive agents, and antiandrogen agents. Adjuvant treatment includes surgery, laser, and light therapy. However, the efficacy of these treatment modalities varies from person to person. In recent years, related reports have shown that injection of botulinum toxin type A has a positive effect in the management of HS. This article reviews the pathogenesis, clinical manifestations, diagnosis, and traditional treatment methods for the management of HS and investigates the use of botulinum toxin type A as a treatment option for this disease.

Dietary and metabolic factors in the pathogenesis of hidradenitis suppurativa: a systematic review

Hidradenitis suppurativa (HS) is a systemic recalcitrant inflammatory condition characterized by debilitating lesions with high morbidity. Its known association with obesity and smoking indicate correlation with other environmental factors, such as diet, suggesting a larger role for lifestyle modifications in disease treatment. This study seeks to assess the contribution of weight loss and dietary intake in HS management. A primary literature search was conducted using PubMed, Web of Science, and CINAHL in November 2018 to include association and intervention studies on the influence of diet and weight on HS. Twenty-five articles were included. Meta-analysis of nine case-control studies across Asia, Europe, and the United States showed that HS patients are four times more likely to be obese compared to the general population; random effects pooled odds ratio 4.022 (2.667-6.065), P < 0.001. Five articles assessed weight-loss interventions and revealed mixed findings. The remaining articles included three association studies on micronutrient levels, eight dietary intervention studies, and one article analyzing both micronutrient association and dietary intervention. Included articles in this systematic review reveal that low serum zinc and vitamin D levels are associated with increased lesion count in HS. Supplementation of zinc, vitamin D, vitamin B12, or exclusion of dairy or brewer's yeast can be effective in partial or complete lesion resolution. Reviewed data show that weight loss from bariatric surgery may lead to HS improvement but often results in more severe malnutrition that worsens or even leads to new onset HS post bariatric surgery. Future reporting is needed to conclusively determine the role of diet in HS.