Acne inversa: evaluating antimicrobial peptides and proteins

Topical and Systemic Retinoids in the Management of Hidradenitis Suppurativa: A Comprehensive Literature Review

Hidradenitis suppurativa (HS) is a debilitating chronic skin disorder characterized by painful inflammatory nodules, abscesses and sinus tracts involving intertriginous areas and has an adverse impact on patient quality of life. Over the past decade, the therapeutic options of HS have increased significantly to comprise multiple modalities, including topical medication, systemic therapies (mainly antibiotics, retinoids, and biologics), surgical approaches, and lifestyle modifications. Biologics alone or in combination with surgery remain the treatment of choice for moderate to severe disease. However, non-biologic therapies (including retinoids) may be used as monotherapy for mild disease and in combination with biologics and surgical treatment in moderate to severe disease. Retinoids, specifically isotretinoin, acitretin, and alitretinoin, are historically used in the management of HS, supported by anecdotal evidence and with variable treatment response. Although the current American and European guidelines offer different recommendations on the use of retinoids in HS, retinoids remain a valuable ally in HS management. This review provides a comprehensive analysis of the current scientific literature on retinoid therapy (topical and systemic) in HS, highlighting disparities in mechanisms of action, efficacy, and safety to clarify their role in HS treatment.

Increased cancer incidence among patients with hidradenitis suppurativa - a Danish nationwide register study 1977-2017

BACKGROUND

The chronic, inflammatory skin disease hidradenitis suppurativa (HS) (prevalence: 0.5%-1%, diagnostic delay: 7-10 years) primarily arises in younger adults and frequently coincides with autoimmune comorbidities and unhealthy life-styles (smoking and obesity). These factors are known to increase cancer risk, but despite this, information on cancer occurrence among HS patients is scarce.

MATERIALS AND METHODS

A nationwide retrospective register-based study assessing relative risk of cancer - overall and by anatomical site - following HS diagnosis expressed as standardized incidence ratios (SIRs), which is ratios between observed cases among all Danes diagnosed with HS since 1977 and expected cases based on cancer incidence rates of the entire Danish population during the same period.

RESULTS

Participants consisted of a cohort of 13,919 Danes with HS, who during an average of 14.2 years of follow-up developed a total of 1,193 incident cancers, corresponding to a 40% increased risk (SIR = 1.4, 95% CI: 1.3 to 1.4, p < 0.001). Increased risks were observed for cancers of the respiratory system, oral cavity and pharynx, digestive organs and peritoneum, urinary tract, and the lymphatic tissues.

INTERPRETATION

These findings underline an unmet need for health monitoring, lifestyle interventions and cancer screening if and when relevant.

The genetic aspects of hidradenitis suppurativa

Genetic aspects have a substantial role in hidradenitis suppurativa (HS) pathogenesis. A positive family history of HS occurs in about one-third of HS cases and is significantly higher in patients with early onset of the disease. Recent twin studies have shown a high heritability in HS, fortifying the importance of genetic factors in disease pathogenesis. Based on existing knowledge on the genomics of HS, the disease can be categorized as familial HS, sporadic, syndromic HS, and "HS plus" associated with other syndromes. In familial HS, autosomal dominant transmission is proposed, and monogenic inheritance is rare. This monogenic trait is related to mutations of γ-secretase component genes and Notch signaling or defects in inflammasome function. With newly discovered gene mutations, such as those related to innate and adaptive immunity, skin microbiome, inflammasome, epidermal homeostasis, and keratinization pathway, we can define HS as a polygenic, multifactorial, autoinflammatory disease. To fully elucidate the genetic aspects of HS, we need extensive, long-term global collaborations.

IL-17A is a pertinent therapeutic target for moderate-to-severe hidradenitis suppurativa: Combined results from a pre-clinical and phase II proof-of-concept study

Hidradenitis Suppurativa (HS) is a chronic, recurrent, inflammatory, follicular skin disease whose pathology is complex and not fully understood. The objective of this study was to elucidate the role of IL-17A in moderate-to-severe HS. Transcriptomic and histological analyses were conducted on ex vivo HS (n = 19; lesional and non-lesional) and healthy control (n = 8) skin biopsies. Further, a Phase II exploratory, randomized, double-blind, placebo-controlled study was carried out in moderate-to-severe HS patients. Patients were treated with either CJM112 300 mg (n = 33), a fully human anti-IL-17A IgG1/κ monoclonal antibody, or placebo (n = 33). The main outcome of the translational analyses was to identify IL-17A-producing cells and indications of IL-17A activity in HS lesional skin. The primary objective of the clinical study was to determine the efficacy of CJM112 in moderate-to-severe HS patients by HS-Physician Global Assessment (HS-PGA) responder rate at Week 16. Transcriptomic and histopathologic analyses revealed the presence of heterogeneous cell types in HS lesional skin; IL-17A gene signatures were increased in HS lesional vs non-lesional or healthy skin. High expression of IL-17A was localized to T cells, neutrophils, and mast cells, confirming the transcriptional data. Clinically, the proportion of Week 16 HS-PGA responders was significantly higher (p = 0.03) in the CJM112 group vs placebo (32.3% vs 12.5%). This study elucidated the role of the IL-17A pathway in HS pathogenesis and clinically validated the IL-17A pathway in moderate-to-severe HS patients in a proof-of-concept study using the anti-IL-17A-specific antibody CJM112.

Innate immunity and microbial dysbiosis in hidradenitis suppurativa – vicious cycle of chronic inflammation

Hidradenitis Suppurativa (HS) is a chronic multifactorial inflammatory skin disease with incompletely understood mechanisms of disease pathology. HS is characterized by aberrant activation of the innate immune system, resulting in activation of pathways that aim to protect against pathogenic microorganisms, and also contribute to failure to resolve inflammation. Imbalance in innate immunity is evident in deregulation of host antimicrobial peptides (AMPs) and the complement system associated with the microbiome dysbiosis. The pathology is further complicated by ability of pathogens associated with HS to overcome host immune response. Potential roles of major AMPs, cathelicidin, defensins, dermcidin, S100 proteins, RNAse 7 and complement proteins are discussed. Dysregulated expression pattern of innate immunity components in conjunction with bacterial component of the disease warrants consideration of novel treatment approaches targeting both host immunity and pathogenic microbiome in HS.

Dissecting cellulitis of the scalp associated with peripheral and axial spondyloarthritis: report of a case and review of the literature

Dissecting cellulitis of the scalp (DCS) is a rare, primary neutrophilic cicatricial alopecia of unknown etiology. The disease follows a chronic, relapsing, and remitting course which may ultimately lead to scar formation and alopecia. The association of seronegative peripheral and/or axial spondyloarthritis in patients with hidradenitis suppurativa (HS) and acne conglobata (AC) is well established. However, the occurrence of spondyloarthropathy in patients with either isolated or combined DCS is relatively rare and therefore underrecognized by clinicians. We report a patient with DCS with inflammatory peripheral arthritis and asymptomatic radiographic sacroiliitis. Using PubMed, Ovid, and Google scholar, we searched for case reports of inflammatory arthritis in HS, AC, and DCS in the English literature from 1982 to present. We identified 12 patients with DCS who had associated spondyloarthropathy with adequate clinical details for a systematic analysis. We outline key clinical features, radiographic findings, and treatment utilized for these patients. Seronegative axial and peripheral spondyloarthritis may occur in the setting of isolated DCS as well with concomitant HS and AC. The inflammatory arthritis often develops during acute flares of the cutaneous disease. Choosing optimal drug therapy may be challenging. Current options include anti-TNF-α medications, which have been reported to be effective for both the cutaneous lesions and the associated spondyloarthritis. The complex pathophysiology of the conditions that comprise the follicular occlusion triad warrants further research into the potential role of additional biologic agents.

Autoantibodies Present in Hidradenitis Suppurativa Correlate with Disease Severity and Promote the Release of Proinflammatory Cytokines in Macrophages

Hidradenitis suppurativa (HS), also known as acne inversa, is a debilitating inflammatory skin disorder that is characterized by nodules that lead to the development of connected tunnels and scars as it progresses from Hurley stages I to III. HS has been associated with several autoimmune diseases, including inflammatory bowel disease and spondyloarthritis. We previously reported dysregulation of humoral immune responses in HS, characterized by elevated serum total IgG, B-cell activation, and antibodies recognizing citrullinated proteins. In this study, we characterized IgG autoreactivity in HS sera and lesional skin compared with those in normal healthy controls using an array-based high-throughput autoantibody screening. The Cy3-labeled anti-human assay showed the presence of autoantibodies against nuclear antigens, cytokines, cytoplasmic proteins, extracellular matrix proteins, neutrophil proteins, and citrullinated antigens. Most of these autoantibodies were significantly elevated in stages II‒III in HS sera and stage III in HS skin lesions compared with those of healthy controls. Furthermore, immune complexes containing both native and citrullinated versions of antigens can activate M1 and M2 macrophages to release proinflammatory cytokines such as TNF-α, IL-8, IL-6, and IL-12. Taken together, the identification of specific IgG autoantibodies that recognize circulating and tissue antigens in HS suggests an autoimmune mechanism and uncovers putative therapeutic targets.

Primary alterations during the development of hidradenitis suppurativa

Background

Hidradenitis suppurativa (HS) is a chronic, inflammatory disease of the apocrine gland‐rich (AGR) skin region. The initial steps of disease development are not fully understood, despite intense investigations into immune alterations in lesional HS skin.

Objectives

We aimed to systematically investigate the inflammatory molecules involved in three stages of HS pathogenesis, including healthy AGR, non‐lesional HS and lesional HS skin, with the parallel application of multiple mRNA and protein‐based methods.

Methods

Immune cell counts (T cells, dendritic cells, macrophages), Th1/Th17‐related molecules (IL‐12B, TBX21, IFNG, TNFA, IL‐17, IL10, IL‐23A, TGFB1, RORC, CCL20), keratinocyte‐related sensors (TLR2,4), mediators (S100A7, S100A8, S100A9, DEFB4B, LCN2, CAMP, CCL2) and pro‐inflammatory molecules (IL1B, IL6, TNFA, IL‐23A) were investigated in the three groups by RNASeq, RT‐qPCR, immunohistochemistry and immunofluorescence.

Results

Epidermal changes were already detectable in non‐lesional HS skin; the epidermal occurrence of antimicrobial peptides (AMPs), IL‐1β, TNF‐α and IL‐23 was highly upregulated compared with healthy AGR skin. In lesional HS epidermis, TNF‐α and IL‐1β expression remained at high levels while AMPs and IL‐23 increased even more compared with non‐lesional skin. In the dermis of non‐lesional HS skin, signs of inflammation were barely detectable (vs. AGR), while in the lesional dermis, the number of inflammatory cells and Th1/Th17‐related mediators were significantly elevated.

Conclusions

Our findings that non‐lesional HS epidermal keratinocytes produce not only AMPs and IL‐1β but also high levels of TNF‐α and IL‐23 confirm the driver role of keratinocytes in HS pathogenesis and highlight the possible role of keratinocytes in the transformation of non‐inflammatory Th17 cells (of healthy AGR skin) into inflammatory cells (of HS) via the production of these mediators. The fact that epidermal TNF‐α and IL‐23 appear also in non‐lesional HS seems to prove these cytokines as excellent therapeutic targets.

Decreased Serum Level of Interleukin-22 Correlates with Hepcidin in Patients with Hidradenitis Suppurativa

Current understanding of the underlying pathophysiology of hidradenitis suppurativa (HS) links the disease with proinflammatory activation and autoimmune processes. This study investigated serum levels of interleukin (IL)-22, a cytokine critically involved in epithelial homeostasis, in the context of the broad clinical spectrum of patients with HS. The study also assessed the relationship between serum IL-22 and pro-inflammatory activation (as evidenced by serum level of IL-6) and serum hepcidin (central regulator of systemic iron homeostasis). Serum concentrations of IL-22 were assessed in 74 patients with HS and 15 healthy subjects. Compared with healthy controls, patients with HS demonstrated decreased levels of serum IL-22 (median; interquartile range (IQR): 12.4 pg/ml (9.8; 23.5) vs 34.8 pg/ml (24.8; 39.8), p < 0.001 vs controls). Disease severity (assessed both with Hurley staging and Hidradenitis Suppurativa Severity Index) did not differentiate IL-22 levels (p > 0.1 in both comparisons). Serum levels of IL-22 and IL-6 did not correlate with each other (R=-0.17, p = ns). In a subgroup of 24 patients with HS with pro-inflammatory activation, the mean level of IL-22 was similar to that of the remaining patients (median (IQR): 9.8 pg/ml (8.5; 15.0) vs 12.0 pg/ml (9.4; 16.3), p = ns). Patients with HS demonstrated a decreased level of hepcidin (mean: 31.3 ± 25.9 pg/ml), which correlated with the levels of IL-22 (R=0.36, p <0.05). Patients with HS demonstrated significantly decreased levels of serum IL-22, which was neither correlated with pro-inflammatory status nor associated with disease severity, but correlated modestly with serum hepcidin.

Antimicrobial peptides in hidradenitis suppurativa: a systematic review

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease of the hair follicle defined by recurrent nodules, tunnels and scarring involving the intertriginous regions. HS is associated with microbial dysbiosis and immune dysregulation. In HS, an increasing number of studies have investigated antimicrobial peptides (AMPs).

OBJECTIVES

To provide an overview of the literature on AMPs in HS, and to discuss the potential role of AMPs in the pathogenesis of HS.

METHODS

PubMed, Embase and the Cochrane Library were searched. The titles, abstracts and full texts of all articles were manually screened. Additionally, the reference lists of the included articles were screened and hand searched for relevant studies.

RESULTS

The final literature sample comprised 18 retrospective and prospective studies (no reviews or commentaries) published between 2009 and 2020.

CONCLUSIONS

This review demonstrates the multitude of AMPs in HS. Although the methodology of the studies varied, the included studies indicate a consistent overexpression of human β-defensin (hBD)-2, S100A7, S100A8 and S100A9 at both the mRNA and protein levels, and a decreased expression of hBD-1. Overall, the studies point to a dysregulation of AMPs in both lesional and nonlesional HS skin.

Insights into the Pathogenesis of HS and Therapeutical Approaches

Hidradenitis suppurativa (HS) is a debilitating, chronic, (auto)inflammatory disease primarily affecting apocrine gland-rich areas of the body. Although pathogenic mechanisms responsible for HS have not yet been fully elucidated, it is a multifactorial process whose main target is the terminal follicle. The role of the inflammatory process (and consequently of cytokine milieu) and of several other factors (genetics, lifestyle, hormonal status, microbiome, innate and adaptive immune systems) involved in HS pathogenesis has been investigated (and often defined) over the years with a view to transferring research results from bench to bedside and describing a unique and universally accepted pathogenetic model. This review will update readers on recent advances in our understanding of HS pathogenesis and novel (potential) medical therapies for patients with moderate-to-severe HS.

Hidradenitis suppurativa: A folliculotropic disease of innate immune barrier dysfunction?

The innate immune system of human skin consists of a multi-layered barrier consisting of cells and soluble effector molecules charged with maintaining homeostasis and responding to insults and infections. It has become increasingly clear that these barrier layers become compromised in skin diseases, especially in disorders of an (auto)inflammatory nature. In the case of hidradenitis suppurativa, great strides have been made in recent years in characterizing the underlying breakdown in homeostatic innate immunity, including an increasing understanding of the central role of the hair follicle in this process. This breakdown appears to occur at multiple levels: the pilosebaceous unit, associated epithelium, the cutaneous microbiome, alteration of immune cell function and local molecular events such as complement activation. This review seeks to summarize, contextualize and analyse critically our current understanding of how these innate immune barriers become dysregulated in the early stage(s) of hidradenitis suppurativa, and to speculate on where potential hidradenitis suppurativa research could be most fruitful.

Yin and Yang: A disrupted skin microbiome and an aberrant host immune response in hidradenitis suppurativa

The skin microbiome plays an important role in maintaining skin homeostasis by controlling inflammation, providing immune education and maintaining host defense. However, in many inflammatory skin disorders the skin microbiome is disrupted. This dysbiotic community may contribute to disease initiation or exacerbation through the induction of aberrant immune responses in the absence of infection. Hidradenitis suppurativa (HS) is a complex, multifaceted disease involving the skin, innate and adaptive immunity, microbiota and environmental stimuli. Herein, we discuss the current state of HS skin microbiome research and how microbiome components may activate pattern recognition receptor (PRR) pathways, metabolite sensing pathways and antigenic receptors to drive antimicrobial peptide, cytokine, miRNA and adaptive immune cell responses in HS. We highlight the major open questions that remain to be addressed and how antibiotic therapies for HS likely influence both microbial burden and inflammation. Ultimately, we hypothesize that the two-way communication between the skin microbiome and host immune response in HS skin generates a chronic positive feed-forward loop that perpetuates chronic inflammation, tissue destruction and disease exacerbation.

Assessment of Overall and Specific Cancer Risks in Patients With Hidradenitis Suppurativa

Importance

Large population-based studies investigating the risks of overall and specific cancers among patients with hidradenitis suppurativa (HS) are limited.

Objective

To assess the overall and specific cancer risks in patients with HS compared with the risks in patients without HS in the Republic of Korea.

Design, Setting, and Participants

A nationwide population-based cohort study, using the Korean Health Insurance Review and Assessment Service database was conducted over a 2-year period from January 1, 2007, to December 31, 2008. Individuals in the control group who were never diagnosed with HS or cancer during the washout period were randomly extracted and matched by age, sex, index year, and insurance type at a case-control ratio of 1:8, and patients with newly diagnosed HS between January 1, 2009, and December 31, 2017, were included. Follow-up data on incident cancer from January 1, 2009, to December 31, 2018, were included.

Main Outcomes and Measures

The overall and specific cancer incidence rates were calculated per 100 000 person-years in patients with HS and in the matched control cohort. The risk for cancers was assessed by multivariable Cox regression models in patients with HS compared with the matched control cohort.

Results

In total, 22 468 patients with HS and 179 734 matched controls were included in the study. The mean (SD) age was 33.63 (17.61) years and 63.7% of the participants in both groups were male. The adjusted hazard ratio (aHR) of overall cancer in patients with HS was 1.28 (95% CI, 1.15-1.42). Patients with HS had significantly higher risk for Hodgkin lymphoma (aHR, 5.08; 95% CI, 1.21-21.36), oral cavity and pharyngeal cancer (aHR, 3.10; 95% CI, 1.60-6.02), central nervous system cancer (aHR, 2.40; 95% CI, 1.22-4.70), nonmelanoma skin cancer (HR, 2.06; 95% CI, 1.12-3.79), prostate cancer (aHR, 2.05; 95% CI, 1.30-3.24), and colorectal cancer (aHR, 1.45; 95% CI, 1.09-1.93).

Conclusions and Relevance

In this study, HS appeared to be associated with a significantly increased risk of overall cancer as well as several specific cancers.

Serum Concentration and Skin Expression of S100A7 (Psoriasin) in Patients Suffering from Hidradenitis Suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. An important role of innate immune dysregulation in the pathogenesis of HS has been highlighted. S100A7 (psoriasin) is an innate, antimicrobial protein that exerts proinflammatory and chemotactic action.

OBJECTIVES

The objective of the study was to investigate serum concentrations of S100A7 in individuals with HS as compared to healthy controls. Further, we evaluated the expression of S100A7 in lesional HS skin as compared to perilesional (clinically uninvolved) HS skin and normal skin.

METHODS

Serum concentrations of S100A7 were evaluated with a commercially available ELISA kit. The expression of S100A7 in the skin was assessed using qRT-PCR and immunofluorescence staining.

RESULTS

We found increased expression of S100A7 in lesional HS skin as compared to perilesional HS skin (p = 0.0017). The expression of S100A7 in lesional HS skin was positively associated with serum C-reactive protein concentration and the severity of disease according to Hurley staging. The serum concentration of S100A7 in individuals with HS was decreased as compared to healthy controls and patients with psoriasis.

CONCLUSIONS

Upregulated in lesional HS skin, S100A7 may enhance the inflammatory process and contribute to the HS pathogenesis.

Cytokine Pathways and Investigational Target Therapies in Hidradenitis Suppurativa

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease affecting areas with a high density of apocrine glands and characterized by subcutaneous nodules that may evolve into fistulas with pus secretion. Methods: The aim of this review is to investigate all current knowledge on cytokine regulation in the pathogenesis of HS. A systematic literature research using the words “cytokine”, “interleukin”, “pathway”, and “hidradenitis suppurativa” was performed in PubMed/Medline and Scopus/Embase databases. A search of the clinicaltrials.gov website for interventional recruiting and completed trials including the term “hidradenitis suppurativa” was also performed up to August 2020. We will discuss the pathogenetic role of various cytokines in HS and potential therapeutic targets for this debilitating disease. Results: The pathophysiology underlying this complex condition has not been clearly defined. An upregulation of various cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1, IL-17, IL-23, and other molecules seems to be related to this inflammatory condition. Various cells, such as lymphocytes T Helper 1 and 17 and keratinocytes seem to be involved in the genesis of this condition. Conclusions: Several future studies and clinical trials are necessary in order to have new knowledge about HS and to properly treat this complex condition.

Metabolic, pharmacokinetic, and toxicological issues of biologic therapies currently used in the treatment of hidradenitis suppurativa

INTRODUCTION

Hidradenitis suppurativa is a chronic, relapsing, debilitating inflammatory dermatologic disease of the terminal hair follicles at intertriginous sites clinically characterized by painful inflammatory nodules, abscesses, draining sinus tracts, and dermal fibrosis. The management of hidradenitis suppurativa is a challenge and usually consists of both medical and surgical approaches, which must often be combined for best outcome. The introduction of biological therapies, specifically TNFα-inhibitors such as adalimumab, has profoundly changed the therapeutic armamentarium of the disease.

AREAS COVERED

The PubMed database was searched using combinations of the following keywords: hidradentis suppurativa, biologic therapy, TNF-α inhibitors, adalimumab, etanercept, infliximab, certolizumab pegol, golimumab, adverse effects, pharmacodynamics, pharmacology, adverse events, pharmacokinetics, drug interaction. This article reviews and updates the chemistry, pharmacokinetics, mechanism of action, adverse effects, drug interactions of on-label and off-label use of TNF-α inhibitors in HS.

EXPERT OPINION

Biologic agents, particularly adalimumab, exhibit clinical efficacy in patients with hidradenitis suppurativa. Careful patient selection and close monitoring during treatment are mandatory to provide safe and effective use of the TNF-α inhibitor. Familiarity with biologic agents is crucial because these agents could become a consolidated treatment option in the clinician's therapeutic approaches.

Identification of Hidradenitis Suppurativa-Related mRNA Expression Patterns Through Analysis of Gene Expression Omnibus

Background:

Hidradenitis suppurativa (HS) is a chronic, follicular, and inflammatory skin disease with multifactorial pathogenesis, and its definite molecule mechanism is still not fully elucidated.

Objective:

The purpose of this research was to identify crucial differentially expressed genes (DEGs) and biological processes and pathways involved in HS through bioinformatics analysis.

Methods:

A total of 30 tissues from patients with HS, 17 lesional and 13 healthy, were obtained from the GSE72702 data set of the Gene Expression Omnibus database. The DEGs were sorted by GEO2R and analyzed by Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis. MCODE analysis was visualized using Cytoscape.

Results:

Of the 723 identified DEGs, 364 were upregulated and 359 were downregulated. Upregulated DEGs were significantly enriched in immune response, inflammatory response, tumor necrosis factor signaling pathway, and so on and downregulated DEGs were enriched in the positive regulation of the peroxisome proliferators-activated receptor pathways, the regulation of lipolysis in adipocytes, and so on. The most significant DEGs group of 35 genes were screened.

Conclusion:

The internal biological information in HS can be revealed by bioinformatic methods, providing direction for further research and potential therapeutic targets.

Comparative Overall Comorbidity Burden Among Patients With Hidradenitis Suppurativa

Importance

The overall comorbidity burden among patients with hidradenitis suppurativa (HS) has not been systematically evaluated.

Objectives

To investigate the standardized overall comorbidity burden among patients with HS and to compare it with the comorbidity burden in patients with psoriasis and a control group.

Design, Setting, and Participants

A cross-sectional analysis was conducted of 5306 patients with HS, 14 037 patients with psoriasis, and 1 733 810 controls identified using electronic health records data from October 1, 2013, through October 1, 2018.

Main Outcome and Measure

The primary outcome was the mean Charlson Comorbidity Index (CCI) score.

Results

Each matched cohort had 3818 patients (2789 women and 1029 men; mean [SD] age, 45.7 [15.0]). Before matching, the overall mean (SD) CCI score was highest among the psoriasis cohort (2.33 [3.13]), followed by the HS cohort (1.80 [2.79]) and control cohort (1.26 [2.35]). In matched analyses, the overall mean (SD) CCI score was highest among the HS cohort (1.95 [2.96]), followed by the psoriasis cohort (1.47 [2.43]; P < .001) and control cohort (0.95 [1.99]; P < .001) patients. A total of 516 patients with HS (13.5%) had an overall mean CCI score of 5 or greater. Mean CCI score was highest for patients with HS across all sex, race, and age groups. The most common comorbidities among patients with HS were chronic pulmonary disease (1540 [40.3%]), diabetes with chronic complications (365 [9.6%]), diabetes without chronic complications (927 [24.3%]), and mild liver disease (455 [11.9%]). Patients with HS with a CCI score of 5 or greater had 4.97 (95% CI, 1.49-16.63) times the adjusted risk of 5-year mortality compared with patients with HS with a CCI score of zero.

Conclusions and Relevance

Patients with HS have a higher overall comorbidity burden compared with patients with psoriasis and a control group. A significant proportion of patients with HS have CCI scores of 5 or greater, which are associated with increased mortality. This degree of comorbidity burden may warrant multidisciplinary implementation of routine screening measures.

Hidradenitis suppurativa: infection, autoimmunity, or both?

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease mainly affecting areas rich in apocrine glands. Clinically, is characterized by painful subcutaneous nodules and if left untreated to pus secretion, abscess and fistula formation. Its frequency is estimated to be 0.5-4% of the general population, affecting women more often. Pathogenesis of HS is still not clearly defined. It seems to be a combination of genetic factors with alterations in the skin microbiome. Furthermore, at tissue (i.e. skin) as well as at serum level, several inflammatory cytokines are upregulated. The most important of the latter are tumor necrosis factor (TNF), interleukin (IL)-1, IL-17, and IL-23. Adding another level of complexity, it has been suggested that keratinocytes might be intrinsically activated, contributing also to the observed inflammation. Interestingly, it has been noted that frequency of HS is increased in some autoimmune rheumatic diseases, such as spondyloarthropathies (SpA). Of note, both HS and SpA have relatively strong association with metabolic diseases and obesity implying that there are indeed some common underlying pathophysiological pathways. Although no specific microbe has been identified, alterations in the microbiome of the skin of these patients have been reported. Of note, microbes with a capability for biofilm formation are abundant. Treatment of HS among others, include antibiotics as well as biologic drugs targeting TNF and other cytokines and used for autoimmune rheumatic diseases. Herein, we review the current evidence on links between HS and autoimmune diseases and infectious diseases with a focus on epidemiology and pathophysiology.

Biologic Treatment for Hidradenitis Suppurativa

Patients with hidradenitis suppurativa (HS) are often undertreated and there are limited efficacious therapies available for treating this population. Biologics are an emerging therapeutic modality used in the management of many inflammatory conditions including HS. Implementation of biologics is typically reserved for moderate-to-severe cases or in those cases that are refractory to treatment. Though many biologics have been trialed for use in HS, only one biologic, adalimumab, is currently US FDA (Food and Drug Administration) approved for the treatment of moderate-to-severe HS. Limitations in the use of biologics for HS include the many scoring systems utilized in research studies and the relatively few well-designed, adequately powered clinical trials.

Hidradenitis Suppurativa: Comprehensive Review of Predisposing Genetic Mutations and Changes

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder. A genetic component in the pathogenesis is highly likely considering that ~30% to 40% of patients with HS report a family history of the disease. The genetic mutations related to HS that have been reported to date suggest HS can be inherited as a monogenic trait because of a defect in either the Notch signaling pathway or inflammasome function, or as a polygenic disorder resulting from defects in genes regulating epidermal proliferation, ceramide production, or in immune system function. This review provides a summary of genetic mutations reported in patients diagnosed with HS and discusses the mechanisms by which these genes are involved in its pathogenesis.

Consensus on the treatment of hidradenitis suppurativa - Brazilian Society of Dermatology

Hidradenitis suppurativa is a chronic immune mediated disease of universal distribution that causes great damage to the quality of life of the affected individual, whose prevalence is estimated at 0.41% in the Brazilian population. The objective of this work was update on physiopathogenesis, diagnosis and classification of hidradenitis suppurativa and to establish therapeutic recommendations in the Brazilian reality. It was organized as a work group composed of eight dermatologists from several institutions of the country with experience in the treatment of hidradenitis suppurativa and carried out review on the topic. Recommendations were elaborated and voted by modified Delphi system and statistical analysis of the results was performed. The Brazilian consensus on the clinical approach of hidradenitis suppurativa had the support of the Brazilian Society of Dermatology.

Association of Hidradenitis Suppurativa With T Helper 1/T Helper 17 Phenotypes: A Semantic Map Analysis

Importance

In spite of progress in understanding the mechanisms underlying hidradenitis suppurativa (HS) as an inflammatory skin disease, there is still a demand for an overview on immunopathogenesis of HS.

Objective

To demonstrate the importance of the type 1/type 17 immune response in lesional HS skin by drawing a semantic connectivity map.

Design, Setting, and Participants

Single-center case series of 24 patients with HS. Association of HS with T helper 1/T helper 17 (TH1/TH17) phenotype was assessed using semantic map analysis.

Main Outcomes and Measures

Association of HS with TH1/TH17 phenotype.

Results

The analysis was performed on 24 lesional HS biopsy samples from untreated patients with HS (16 [67%] female; median age, 36.5 years [range, 21-51 years]) with a mean (SD) Hurley stage of 2.29 (0.62) and 9 punch biopsy samples from healthy controls (6 [67%] female; median age, 43 years [range, 23-66 years]). The map shows a clustering of all TH1/TH17-associated cytokines (interleukin 17 [IL-17], interferon γ, IL-12, IL-23, IL-32, IL-1β, tumor necrosis factor) around overall lesional inflammation. Tumor necrosis factor, IL-12, and IL-17 are even directly connected via interferon γ. In contrast, IL-13, a TH2-associated cytokine, was inversely correlated with the presence of TH1/TH17-associated cytokines, further highlighting the importance of the TH1/TH17 cytokines in HS pathogenesis.

Conclusions and Relevance

These findings suggest that HS may be a TH1/TH17-driven inflammatory skin disease.

The skin transcriptome in hidradenitis suppurativa uncovers an antimicrobial and sweat gland gene signature which has distinct overlap with wounded skin

Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory skin disease resulting in non-healing wounds affecting body areas of high hair follicle and sweat gland density. The pathogenesis of HS is not well understood but appears to involve dysbiosis-driven aberrant activation of the innate immune system leading to excessive inflammation. Marked dysregulation of antimicrobial peptides and proteins (AMPs) in HS is observed, which may contribute to this sustained inflammation. Here, we analyzed HS skin transcriptomes from previously published studies and integrated these findings through a comparative analysis with a published wound healing data set and with immunofluorescence and qPCR analysis from new HS patient samples. Among the top differently expressed genes between lesional and non-lesional HS skin were members of the S100 family as well as dermcidin, the latter known as a sweat gland-associated AMP and one of the most downregulated genes in HS lesions. Interestingly, many genes associated with sweat gland function, such as secretoglobins and aquaporin 5, were decreased in HS lesional skin and we discovered that these genes demonstrated opposite expression profiles in healing skin. Conversely, HS lesional and wounded skin shared a common gene signature including genes encoding for S100 proteins, defensins, and genes encoding antiviral proteins. Overall, our results suggest that the pathogenesis of HS may be driven by changes in AMP expression and altered sweat gland function, and may share a similar pathology with chronic wounds.

An Integrated Approach to Unravel Hidradenitis Suppurativa Etiopathogenesis

Hidradenitis suppurativa/acne inversa (HS) is a chronic inflammatory disease involving hair follicles that presents with painful nodules, abscesses, fistulae, and hypertrophic scars, typically occurring in apocrine gland bearing skin. Establishing a diagnosis of HS may take up to 7 years after disease onset. HS severely impairs the quality of life of patients and its high frequency causes significant costs for health care system. HS patients have an increased risk of developing associated diseases, such as inflammatory bowel diseases and spondyloarthropathies, thereby suggesting a common pathophysiological mechanism. Familial cases, which are around 35% of HS patients, have allowed the identification of susceptibility genes. HS is perceived as a complex disease where environmental factors trigger chronic inflammation in the skin of genetically predisposed individuals. Despite the efforts made to understand HS etiopathogenesis, the exact mechanisms at the basis of the disease need to be still unraveled. In this review, we considered all OMICs studies performed on HS and observed that OMICs contribution in the context of HS appeared as not clear enough and/or rich of useful clinical information. Indeed, most studies focused only on one aspect—genome, transcriptome, or proteome—of the disease, enrolling small numbers of patients. This is quite limiting for the genetic studies, from different geographical areas and looking at a few aspects of HS pathogenesis without any integration of the findings obtained or a comparison among different studies. A strong need for an integrated approach using OMICs tools is required to discover novel actors involved in HS etiopathogenesis. Moreover, we suggest the constitution of consortia to enroll a higher number of patients to be analyzed following common and consensus OMICs strategies. Comparison and integration with the findings present in the OMICs repositories are mandatory. In a theoretic pipeline, the Skin-OMICs profile obtained from each HS patient should be compared and integrated with repositories and literature data by using appropriate InterOMICs approach. The final goal is not only to improve the knowledge of HS etiopathogenesis but also to provide novel tools to the clinicians with the eventual aim of offering a tailored treatment for HS patients.

The anti-inflammatory potency of biologics targeting tumour necrosis factor-α, interleukin (IL)-17A, IL-12/23 and CD20 in hidradenitis suppurativa: an ex vivo study

Background

Biologics targeting inflammatory mediators can achieve clinical improvements in hidradenitis suppurativa (HS). However, their clinical efficacy shows great interpatient variability in daily practice.

Objectives

To investigate the anti‐inflammatory potency of a selection of currently available biologics and prednisolone for the treatment of HS in an ex vivo skin culture system using lesional HS biopsies.

Methods

Lesional skin samples from 10 patients with HS and skin samples from five healthy controls were cultured ex vivo and exposed to prednisolone or biologics targeting tumour necrosis factor (TNF)‐α, interleukin (IL)‐17A, IL‐12/23p40 or CD20 (adalimumab, infliximab, secukinumab, ustekinumab and rituximab, respectively). Real‐time quantitative polymerase chain reaction and cytokine bead arrays were used to measure the inhibitory effect of the biologics on cytokines and antimicrobial peptides (AMPs).

Results

The relative mRNA expression of all tested cytokines and AMPs was significantly downregulated by all anti‐inflammatory agents (P < 0·001). The protein production of the proinflammatory cytokines TNF‐α, interferon γ, IL‐1β, IL‐6 and IL‐17A was significantly inhibited by adalimumab, infliximab, ustekinumab, prednisolone (all P < 0·001) and rituximab (P = 0·0071), but not by secukinumab (P = 0·0663). On both mRNA and protein levels, adalimumab, infliximab and prednisolone reduced the levels of a broader mix of individual cytokines than secukinumab, ustekinumab and rituximab. Moreover, a significant inhibitory effect on mRNA expression levels of inflammatory markers in healthy control skin was observed only for TNF‐α inhibitors (P < 0·001) and prednisolone (P = 0·0015).

Conclusions

This ex vivo study suggests that TNF‐α inhibitors and prednisolone are the most powerful inhibitors of proinflammatory cytokines and AMPs in HS lesional skin, which concurs with our clinical experience in patients with HS.

What's already known about this topic?

A key element of hidradenitis suppurativa (HS) is an aberrant immune response characterized by the overexpression of several proinflammatory cytokines and antimicrobial peptides in lesional skin.

Biologics targeting inflammatory cytokines have the potential to improve HS disease activity.

There is still need for efficacious drugs in the treatment of HS.

What does this study add?

We sought to quantify the anti‐inflammatory effects of currently available biologics in an ex vivo disease model.

Adalimumab, infliximab, secukinumab, ustekinumab and rituximab in addition to prednisolone significantly inhibited a selected panel of proinflammatory cytokines and antimicrobial peptides in ex vivo HS lesional skin.

Adalimumab, infliximab and prednisolone reduced the levels of a broader mix of individual cytokines than secukinumab, ustekinumab and rituximab.

What is the translational message?

The significant inhibition of important proinflammatory cytokines by tumour necrosis factor‐α inhibitors in HS correlates with their clinical efficacy.

Our ex vivo skin culture system represents an adequate model for studies in search of novel candidate drugs for the treatment of HS and to personalize the treatment in specific patients.

Linked Comment: https://doi.org/10.1111/bjd.18173.

https://www.bjdonline.com/article/

Rates of antibiotic resistance/sensitivity in bacterial cultures of hidradenitis suppurativa patients

BACKGROUND

Antibiotic (AB) treatment is one of the first steps in the management of hidradenitis suppurativa (HS). Bacteria, in HS patients, may play a double role, as triggering factors of inflammatory reactions and/or agents of infection.

OBJECTIVES

The aims of this study are as follows: (i) to assess prevalence and AB resistance of bacterial growths in HS patients (ii) assessment of the clinical relevance of obtained data in guiding the selection of the most effective AB therapy.

METHODS

Purulent material from 137 skin lesions of HS patients was collected with swabs. Bacterial flora and AB sensitivity were determined using microbiological cultures for aerobic and anaerobic bacteria.

RESULTS

A total of 114 samples resulted positive for bacteria. Sample was collected from the axillae, groin and perianal areas. A total of 163 single bacterial growths were observed; 55% were Gram-positive and 44% were Gram-negative. Among them, 18.4% were anaerobic. The most frequent bacterial families included enterobacteriaceae (30.7%), Staphylococcus (25.2%) and Streptococcus (14.1%). The most frequent genus or species were proteus spp. (13.5%) and Escherichia coli (9.8%). The prevalence of AB resistance observed was clindamycin 65.7%, rifampicin 69.3%, penicillin 70.0%, ciprofloxacin 74%, tetracycline 84.7% and erythromycin 89.0%. A limitation of the study is represented the short culture period adopted which may have impaired the isolation of anaerobes.

CONCLUSIONS

Bacterial growth in HS patients has shown a high level of resistance to ABs, including rifampicin, clindamycin and tetracyclines, cited as an empiric choice in HS therapeutic guidelines. A targeted and specific AB therapy, driven by microbiological evaluations with prolonged culture periods, seems more appropriate than empiric, generic, non-specific, therapeutic approaches. Current knowledge regarding HS bacterial AB resistance should be considered in the update of current therapeutic guidelines for HS.

Elevated levels of the antimicrobial peptide LL-37 in hidradenitis suppurativa are associated with a Th1/Th17 immune response

Hidradenitis suppurativa (HS) is an inflammatory skin disease with poorly understood immunopathogenic mechanisms. LL-37 is an antimicrobial peptide, which is transcribed from the CAMP (cathelicidin antimicrobial peptide) gene. Previous reports showed upregulated levels of CAMP and LL-37 in HS lesions, and therefore, the aim of this study was to compare levels of LL-37 in HS to other inflammatory skin diseases and to establish immunomodulatory functions of LL-37 in HS. We confirm an upregulation of the LL-37 peptide in lesional HS skin with comparable levels as in psoriasis patients and are able to positively correlate the presence of LL-37 in HS with the presence of T cells, macrophages, neutrophils, IFN-γ, IL-17, IL-23, TNF-α, IL-32 and IL-1β. Mechanistically, LL-37 boosts the proliferation of unspecifically activated CD4⁺ T cells via an increased calcium signalling independent of antigen-presenting cells. Targeting LL-37 may therefore represent a new therapeutic option for the treatment of this recalcitrant disease, but it has to be kept in mind that LL-37 also has an antimicrobial function.

Inherent differences in keratinocyte function in hidradenitis suppurativa: Evidence for the role of IL-22 in disease pathogenesis

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory disease of apocrine gland-bearing skin which affects approximately 1-4% of the population. Defective keratinocyte function has been postulated to play a role in HS pathogenesis. Using an in vitro scratch assay, differences between normal, HS, and chronic wound (CW) keratinocytes were evaluated. Normal keratinocytes exhibited faster scratch closure than HS or CW, with normal samples showing 93.8% closure at 96 hours compared to 80.8% in HS (p = 0.016) and 71.5% in CW (p = 0.0012). The keratinocyte viability was similar in normal and HS (91.12 ± 6.03% and 86.55 ± 3.28%, respectively, p = 0.1583), but reduced in CW (72.34 ± 13.12%, p = 0.0138). Furthermore, apoptosis measured by annexin V/propidium iodide, was higher in CW keratinocytes (32.10 ± 7.29% double negative cells compared to 68.67 ± 10.37% in normal and 55.10 ± 9.46% in HS, p = 0.0075). Normal keratinocytes exhibited a significantly higher level of IL-1α (352.83 ± 42.79 pg/ml) compared to HS (169.96 ± 61.62 pg/ml) and CW (128.23 ± 96.61 pg/ml, p = 0.004). HS keratinocytes exhibited significantly lower amounts of IL-22 (8.01 pg/ml) compared to normal (30.24 ± 10.09 pg/ml) and CW (22.20 ± 4.33 pg/ml, p = 0.0008), suggesting that defects in IL-22 signaling may play a role in HS pathogenesis. These findings support intrinsic differences in keratinocyte function in HS which cannot be attributed to reduced keratinocyte viability or increased apoptosis.

Association of Resilience With Depression and Health-Related Quality of Life for Patients With Hidradenitis Suppurativa

Importance

Hidradenitis suppurativa (HS) places a significant burden on the health-related quality of life (HRQOL) of patients, many of whom have depression. Resilience can play a role in mitigating the negative stressors, such as the symptoms of HS, on patients' mental health.

Objective

To investigate the correlation among resilience, depression, and HRQOL for patients with HS.

Design, Setting, and Participants

This cross-sectional survey study of 154 patients from 2 referral centers in the United States and in Denmark was conducted from June 1, 2016, to March 31, 2017. Patients were considered eligible if they were 18 years or older and had a visit for HS at 1 of the 2 referral centers in the past 2 years (from January 1, 2014, through December 31, 2016). Patients were excluded if they declined to participate, could not read or write in English or Danish, or had a cognitive disability that would preclude their understanding of the survey questions.

Main Outcomes and Measures

The survey instrument included 4 questionnaires: (1) a sociodemographic and clinical characteristics questionnaire, (2) the Brief Resilient Coping Scale, (3) the Hospital Anxiety and Depression Scale, and (4) the Dermatology Life Quality Index. The main outcome of interest was the HRQOL as measured by the Dermatology Life Quality Index.

Results

All 154 patients submitted a completed survey. The mean (SD) age of the participants was 40.93 (13.5) years; most participants were women (130 [84.4%]), and most participants self-identified as white (139 [90.2%]). The rate of depression among the patients in this study was comparable to those reported in previous studies; 55 patients (35.7%) were classified as having depression, and 32 patients (20.8%) had borderline depressive symptoms. Patient-rated HS severity and the depression score each independently estimated 27% and 10% of variation in HRQOL, respectively. The interaction term for resilience and depression was significant, indicating that resilience moderates depression. Analysis of the mediation effects of resilience was not significant, indicating that resilience did not mediate the association between depressive symptoms and HRQOL. The resilience score was significantly associated with depressive symptoms (regression coefficient a = -0.21; P < .001), and the depressive symptoms score (c = 0.637; P < .001) was significantly associated with lower HRQOL (c' = 0.644; P < .001). However, both the direct association (b = 0.033; P = .86) and the indirect association (a × b = 0.007; P = .87) of resilience with HRQOL were not significant.

Conclusions and Relevance

Patients with higher resilience levels experienced a smaller decrease in HRQOL as depressive symptoms increased. Because the findings suggest that resilience can be taught, there is an opportunity to develop a resiliency training program and investigate its role in stress levels and depressive symptoms, as well as in HRQOL and disease activity.

Interleukin-32 is highly expressed in lesions of hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. Its immunopathogenic mechanisms are still poorly understood. Previous studies demonstrated that the proinflammatory cytokine interleukin (IL)-32 is implicated in the pathogenesis of other inflammatory diseases.

OBJECTIVES

To investigate the tissue expression and systemic levels of IL-32, as well as its cellular sources, in patients with HS in comparison with healthy donors and patients with two other inflammatory skin diseases: psoriasis and atopic dermatitis (AD).

METHODS

Tissue samples were obtained from healthy skin and lesional HS, psoriatic and AD skin to analyse the expression of IL-32 by immunohistochemistry and semiquantitative real-time polymerase chain reaction. The cellular source of the cytokine was determined by double immunofluorescence staining. Serum from the four donor groups was used to measure systemic levels of IL-32 by enzyme-linked immunosorbent assay.

RESULTS

IL-32 was upregulated in patients with HS in both lesional skin and serum when compared with healthy donors and patients with AD or psoriasis. In HS, IL-32 was found to be expressed by natural killer cells, T cells, macrophages and dendritic cells in highly infiltrated areas of the dermis. High IL32 mRNA levels in lesional HS skin coincided with high amounts of T cells and macrophages. Additionally, IL32 mRNA levels in lesional HS skin correlate positively with interferon-γ and IL-17A and negatively with IL-13.

CONCLUSIONS

Our findings suggest that IL-32 is overexpressed in HS. Targeting IL-32 may therefore represent a new therapeutic option for the treatment of this recalcitrant disease.

Increased expression of the interleukin-36 cytokines in lesions of hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a recalcitrant chronic skin disease with poorly understood immunopathogenic mechanisms. Previous studies reported that the interleukin-36 (IL-36) cytokines [IL-36α, IL-36β, IL-36γ and IL-36 receptor antagonists (IL-36RA)] are important players in the pathogenesis of psoriasis (PS).

OBJECTIVE

We aim to determine whether the IL-36 cytokines are upregulated in patients with HS. For this purpose, we analysed local expression and systemic levels of the IL-36 cytokines in patients with HS and compared the results to healthy donors and patients with PS.

METHODS

Skin biopsies from healthy donors and HS and PS patients were analysed for expression of the IL-36 cytokines by immunohistochemistry and semiquantitative real-time PCR. The enzyme-linked immunosorbent assay (ELISA) was used to measure systemic levels of the IL-36 cytokines in the serum of the three donor groups.

RESULTS

The agonists IL-36α, IL-36β and IL-36γ were found to be upregulated in HS both systemically and lesionally, while the IL-36RA was not differently regulated in comparison to healthy donors.

CONCLUSION

Our findings suggest that the agonistic IL-36 isoforms are upregulated in HS. The relevance of the enhanced production of IL-36 cytokines in HS pathogenesis remains to be determined.

Review of Current Immunologic Therapies for Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory disease of apocrine gland-bearing skin which affects approximately 1–4% of the population. The disease is more common in women and patients of African American descent and approximately one-third of patients report a family history. Obesity and smoking are known risk factors, but associations with other immune disorders, especially inflammatory bowel disease, are also recognized. The pathogenesis of HS is poorly understood and host innate or adaptive immune response, defective keratinocyte function, and the microbial environment in the hair follicle and apocrine gland have all been postulated to play a role in disease activity. While surgical interventions can be helpful to reduce disease burden, there is a high recurrence rate. Increasingly, data supports targeted immune therapy for HS, and longitudinal studies suggest benefit from these agents, both when used alone and as an adjunct to surgical treatments. The purpose of this review is to outline the current data supporting use of targeted immune therapy in HS management.

Hidradenitis suppurativa: from pathogenesis to diagnosis and treatment

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease primarily affecting apocrine gland-rich areas of the body and presenting with painful nodules, abscesses, sinus tracts, and scarring. HS is a multifactorial disease in which genetic and environmental factors play a key role. The primary defect in HS pathophysiology involves follicular occlusion of the folliculopilosebaceous unit, followed by follicular rupture, and immune responses (perifollicular lympho-histiocytic inflammation), finally leading to the development of clinical HS lesions. HS has a destructive impact on the patient’s quality of life, being a very challenging disease. Available treatments are limited, mostly off-label and with high variability in the reported efficacy. Fortunately, a monoclonal antibody against tumor necrosis factor alpha has been recently approved for treatment of moderate to severe HS, offering patients a promising new option. This review focuses on the main features of HS, including epidemiology, clinical aspects, pathogenesis, severity classifications, comorbidities, and currently available treatments.

Medical and Surgical Treatment of Hidradenitis Suppurativa: A Review

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease presenting with painful nodules, abscesses, sinus tracts, and scarring primarily affecting apocrine gland-rich intertriginous areas. HS prevalence ranges from 0.05 to 1%. The central pathogenic event in HS is believed to be the occlusion of the upper part of the folliculopilosebaceous unit, leading to the rupture of the sebofollicular canal with the consequent development of perifollicular lymphohistiocytic inflammation. The HS treatment choices are influenced by disease severity and its individual subjective impact, involving both medical and surgical interventions. However, given the chronic nature of HS, its destructive impact on social, working, and daily life of patients, its management is often frustrating for both the patient and physician. Hence, prompt and effective management strategies are urgently needed and a multidisciplinary approach is advocated. Therefore, in this article, we highlighted the main features of HS (clinical aspects, epidemiology, pathogenesis, diagnostic criteria, classifications, comorbidities, and treatments), so that awareness of this disease might be heightened in primary care physicians and surgeons, who may be the first health care providers to see patients with this disease owing to its characteristic clinical presentation (inflammatory nodules, abscesses, sinus tract, etc.).

Interferon-gamma (IFN-γ) is Elevated in Wound Exudate from Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic recurrent inflammatory disease of apocrine glands which affects 1-4% of young adults. The purpose of this study was to investigate inflammatory cytokines in effluent from HS lesions and to identify potential local drivers of inflammation in HS. Wound fluid specimens from HS patients (n = 8) and age-matched chronic wound patients (n = 8) were selected for analysis. The hidradenitis suppurativa score (HSS) was used to determine the extent of HS activity. Cytokine analysis was conducted using Meso Scale Discovery cytokine and proinflammatory panels. Interferon-gamma (IFN-γ) was significantly elevated in the HS effluent compared to chronic wounds (1418 ± 1501 pg/ml compared to 102.5 ± 138 pg/ml, p = 0.027). HS effluent also had significantly higher levels of tumor necrosis factor-β (TNF-β) (9.24 ± 7.22 pg/ml compared to 1.65 ± 2.14 pg/ml, p = 0.03). There was no significant difference in any other cytokines. There was no significant difference in demographics in the HS compared to chronic wound cohorts. Mean HSS in the HS cohort was 68.88 (SD ± 41.45). In this proof-of-concept pilot study, IFN-γ was significantly elevated in HS effluent. TNF-β/LT-α levels were also elevated in HS, although the levels were more modest. Further studies should focus on molecular drivers of tissue injury in HS and the relationship between HS effluent cytokine profile and disease activity.

Inflammation induced changes in the expression levels of components of the microRNA maturation machinery Drosha, Dicer, Drosha co-factor DGRC8 and Exportin-5 in inflammatory lesions of hidradenitis suppurativa patients

BACKGROUND

The inflammatory pathogenesis behind the debilitating chronic inflammatory skin disorder hidradenitis suppurativa (HS) is poorly understood. Deregulation of microRNAs (miRNAs) may contribute to the pathogenesis and chronic inflammation in autoimmune and inflammatory diseases. However, there are no data on the expression or function of miRNAs in HS.

OBJECTIVE

To evaluate expression of the miRNA key regulators Drosha, Drosha co-factor DGRC8, Dicer and Exportin-5 in the inflammatory microenvironment of HS.

METHODS

Specimens were harvested from lesional HS skin (n=18), adjacent healthy-appearing HS skin (n=7), lesional psoriatic skin (n=10), and healthy subjects (n=10). To evaluate the quantitative real-time RT-PCR data of Drosha and Dicer a subset of skin samples were studied by immunohistochemistry.

RESULTS

Drosha and DGRC8 were significantly downregulated in healthy-appearing perilesional skin from HS patients compared to healthy controls. There were no significant differences in Drosha, DGRC8 and Exportin-5 expression between lesional HS and lesional psoriatic skin. Notably, Dicer expression levels were not dysregulated in psoriatic skin.

LIMITATIONS

Small sample size and descriptive study design.

CONCLUSIONS

The miRNA key regulators were significantly dysregulated in HS lesions compared to healthy skin. Drosha and DGRC8 are altered in the initial, subclinical inflammatory process in healthy-appearing perilesional skin of HS patients prior to the first visible clinical manifestations. Dicer and Exportin-5 may contribute to the later inflammatory process with visible HS lesions.

Bacteriology of hidradenitis suppurativa/acne inversa: A review

Given that follicular papules and pustules, as well as nodules and abscesses, are the clinical hallmarks of hidradenitis suppurativa (HS), an infectious, bacterial pathway has been suspected in the pathogenesis of this chronic, inflammatory condition. Elucidating the behavior and role of bacterial species in HS and their interaction with cutaneous innate immunity will provide more insight into the pathophysiology of this condition. This review of prospective investigations suggests a synergistic relationship between impaired innate immunity and microbial factors in the etiology of HS.