New insights into the diagnosis of hidradenitis suppurativa: Clinical presentations and phenotypes

Hidradenitis Suppurativa from a Multi-Omic Scope

Hidradenitis suppurativa (HS) is recognized as a systemic immune-mediated disease (IMID), sharing genetic and environmental risk factors with other IMIDs such as inflammatory bowel disease and psoriasis. Over time, correlating clinical findings with genetic, proteomic, and metabolomic results has been challenging due to diverse sampling methods, analysis techniques, and the use of variable clinical phenotype descriptions across studies. This review aims to summarize the results from various omics fields to explore the etiopathology of HS. Genetic studies highlight defects in Notch and γ-secretase signaling and inflammasome function. Syndromic HS involves specific mutations in autoinflammatory syndromes such as pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) and pyoderma gangrenosum, acne, and HS (PASH). Proteomic analyses reveal key inflammatory pathways indicating activation of both innate and adaptive immunity. Additionally, microbiome studies show an increased presence of anaerobes like Prevotella in HS lesions and a decreased presence of commensals such as Staphylococcus epidermidis. Gut microbiota dysbiosis, particularly involving Ruminococcus gnavus and Clostridium ramosum, is associated with HS. Moreover, metabolomic profiling indicates dysregulated tryptophan catabolism and lipid metabolism, with increased 5-lipoxygenase-derived metabolites and odd-chain fatty acids suggesting bacterial involvement. In summary, despite advances, robust associations between genetics, proteomics, microbiome, and metabolomics in HS are still lacking. Integrating these datasets could identify new clinical phenotypes, genetic predispositions, microbial signatures, and therapeutic targets, enhancing personalized treatment strategies and biomarker discovery for HS classification, prognosis, and treatment response.

Factors Associated with Severe Hidradenitis Suppurativa, Using Hurley Staging and Metascore

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease for which certain risk factors are well known: obesity and smoking (in particular). However, the factors associated with more severe conditions, and therefore potential aggravators of the disease, remain a matter of debate. Our study aims to determine the clinical factors associated with severe HS using several severity scores.

METHODS

The data were obtained via the ERHS questionnaire from patients exclusively recruited at Erasme Hospital in Brussels. The severity of HS was firstly estimated by the Hurley score, and secondly by a metascore, a system combining the iHS4, HS-PGA, SAHS, and DLQI. Univariable and multivariable analyses were performed.

RESULTS

Six hundred and forty-seven patients were included in the Hurley analysis, and 456 patients in the metascore analysis. In multivariable analysis, men have a more severe metascore than women (odds ratio [OR] = 1.89, p = 0.022), smoking was associated with a more severe disease according to metascore, especially in mild cases (OR = 0.76, p = 0.043), and an elevated body mass index was associated with having Hurley stage III disease compared to Hurley I or II disease (OR = 1.09, p = 0.001). A significant association is also shown between blood pressure and Hurley stage (OR = 0.97, p = 0.025). Self-reports of nonsteroidal anti-inflammatory drugs aggravating the disease is also a factor associated with greater severity according to the metascore (OR = 0.12, p = 0.008). Finally, several locations of HS lesions were associated with greater severity, in particular the armpits according to the metascore (OR = 0.29, p < 0.001), and the perianal area according to the Hurley score (OR = 0.15, p < 0.001).

CONCLUSION

HS seems to be more severe in men; smoking seems to aggravate mild cases of HS, while increased body mass index plays a major role in the transition from Hurley II to Hurley III.

Comprehensive Catalog of Variants Potentially Associated with Hidradenitis Suppurativa, Including Newly Identified Variants from a Cohort of 100 Patients

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by painful, recurrent abscesses, nodules, and scarring, primarily in skin folds. The exact causes of HS are multifactorial, involving genetic, hormonal, and environmental factors. It is associated with systemic diseases such as metabolic syndrome and inflammatory bowel disease. Genetic studies have identified mutations in the γ-secretase complex that affect Notch signaling pathways critical for skin cell regulation. Despite its high heritability, most reported HS cases do not follow a simple genetic pattern. In this article, we performed whole-exome sequencing (WES) on a cohort of 100 individuals with HS, and we provide a comprehensive review of the variants known to be described or associated with HS. 91 variants were associated with the γ-secretase complex, and 78 variants were associated with other genes involved in the Notch pathway, keratinization, or immune response. Through this new genetic analysis, we have added ten new variants to the existing catalogs. All variants are available in a .vcf file and are provided as a resource for future studies.

Demographic Data, Risk Factors, and Disease Burden of HS Patients in Lithuania at a Reference Center

BACKGROUND

Hidradenitis suppurativa (HS) diagnosis often faces a global delay of 7.2 years due to factors like lack of recognition, stigma, and socioeconomic barriers. Limited effective therapies and frequent exacerbations impact patients' quality of life, posing a significant burden on healthcare systems.

METHODS

HS patients were assessed according to European Hidradenitis Suppurativa Foundation (EHSF) Registry questionnaire guidelines at various stages of the disease and treatment.

RESULTS

The study included 49 patients; 57.14% (n = 28) of them were male. The average age of the subjects was 39.91 ± 13.665 years; the average BMI was 27.84 ± 7.362. A total of 59.18% (n = 29) were active or previous smokers. There were statistically more male smokers than female (p < 0.01). Average disease onset was 25.71 ± 13.743 years; the mean time to diagnosis was 5.2 ± 7.607 years. A total of 70.2% (n = 33) were previously misdiagnosed. Subjects had 6.17 ± 6.98 painful days over the preceding 4 weeks. The average intensity of pain according to the visual analogue scale (VAS) was 5.60 ± 3.36 points. The mean dermatology life quality index (DLQI) at baseline was 8.9 ± 7.436.

CONCLUSIONS

The research revealed delayed diagnoses, especially for females. Smoking was linked to higher Hurley stages, with a prevalence among male smokers, and HS had a substantial impact on patients' quality of life.

Doppler ultrasound protocol for patients with hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that leads to the formation of nodules, abscesses and fistulas, with the formation of scars and fibrosis, causing significant impairment in patient quality of life. The diagnosis is clinical, using scores to classify the severity of the condition; currently the most recommended classification is the International Hidradenitis Suppurativa Severity Scoring System (IHS4). Doppler ultrasound has been used to complement the clinical evaluation of patients with HS. It is possible to observe subclinical lesions that change the staging, the severity of the case, and its treatment, either clinical or surgical. Correct treatment is essential to minimize the consequences of this disease for the patient.

OBJECTIVE

To establish an outpatient protocol for the use of Doppler ultrasound in the care of patients with HS.

METHODS

A narrative review of the literature was carried out on the use of Doppler ultrasound in patients with hidradenitis suppurativa; a referring protocol and technique orientations for imaging assessment in HS were created.

RESULTS

Recommendation to perform ultrasound evaluation of symptomatic areas eight weeks after using antibiotics and four, 12, and 24 weeks after starting immunobiologicals; apply SOS-HS ultrasound severity classification.

STUDY LIMITATIONS

The review did not cover all literature on ultrasound and HS; no systematic review was carried out, but rather a narrative one.

CONCLUSIONS

The correct assessment of patients staging must be carried out using dermatological ultrasound to avoid progression to scars and fibrosis, which compromise patients quality of life.

Essentials of hidradenitis suppurativa: a comprehensive review of diagnostic and treatment perspectives

Hidradenitis suppurativa, or acne inversa, is a chronic inflammatory skin condition with recurrent inflammatory nodules, abscesses, subcutaneous tracts, and scars. This condition may cause severe psychological distress and reduce the quality of life for affected individuals. It is considered to have one of the most damaging effects on quality of life of any skin disorder as a result of the discomfort and foul-smelling discharge from these lesions. Although the pathophysiology of HS is still unclear, multiple factors, including lifestyle, genetic, and hormonal factors, have been associated with it. The pathogenesis of HS is very complex and has wide clinical manifestations; thus, it is quite challenging to manage and often requires the use of combination treatments that must be tailored according to disease severity and other patient-specific factors. Although lifestyle changes, weight loss, quitting smoking, topical treatments, and oral antibiotics are adequate for mild cases, the challenge for healthcare professionals is dealing with moderate-to-severe HS, which often does not respond well to traditional approaches. This literature review, consisting of an overview of the various assessment tools and therapy strategies available for the diagnosis and treatment of HS from published literature, aims to be a guide for practicing clinicians in dealing with the complexities associated with this disease.

Improving hidradenitis suppurativa management: consensus statements from physicians and patients' perspectives

Hidradenitis suppurativa (HS) is a frequent chronic inflammatory skin condition primarily affecting areas rich in apocrine sweat glands, presenting with comedones, papules, nodules, and abscesses, as well as tunnels and hypertrophic scarring. Despite its prevalence and impact on quality of life, the pathogenesis of HS remains incompletely understood. Notably, its diagnosis often suffers from delays and misidentification, therefore an improved education for healthcare providers is mandatory. Moreover, HS is frequently associated with systemic comorbidities and a multidisciplinary approach is suggested for its management. Recognizing these challenges, a group of Italian HS experts and patients convened to develop consensus guidelines via the Nominal Group Technique. Through iterative meetings and remote collaboration, they identified key areas for improvement and formulated consensus statements to guide healthcare providers in delivering optimal care. This collaborative effort highlights the importance of standardized approaches and interdisciplinary collaboration in managing HS effectively.

New insights on hidradenitis suppurativa phenotypes and treatment response: An exploratory automated analysis of the SUNSHINE and SUNRISE trials

BACKGROUND

Defining hidradenitis suppurativa (HS) subtypes was previously limited by small sample sizes and poor interrater reliability; no study has investigated subtype treatment responses. The objective of this analysis was to characterize HS clusters in adult patients with moderate to severe HS and evaluate secukinumab treatment responses between clusters.

METHODS

Clusters were identified via an unsupervised machine learning clustering analysis using baseline data from the randomized, placebo-controlled SUNSHINE (NCT03713619) and SUNRISE (NCT03713632) phase 3 trials. To assess treatment responses, patients received secukinumab every 2 (SECQ2W) or 4 weeks (SECQ4W) or placebo, for 16 weeks, after which, placebo patients randomly switched to SECQ2W/SECQ4W, and SECQ2W/SECQ4W patients maintained their original treatment, until week 52. Baseline outcomes included patient characteristics, disease characteristics and severity, HS-associated comorbidities and previous treatment exposures. Treatment response was assessed via the HS clinical response (HiSCR), abscess and inflammatory nodule (AN) count, flares and NRS30 (skin pain).

RESULTS

Based on baseline data, three clusters were identified from 1084 patients (Cluster 1: 54.1%, Cluster 2: 17.8%, Cluster 3: 28.1%). Cluster 1 was predominantly female (65.4%) and was characterized by milder HS. Cluster 2 had more patients from the Asia Pacific, Middle East and Africa region (58.5%) and was characterized by moderate HS. Cluster 3 had the highest rates of previous exposure to biologics (45.9%) and prior HS-related surgeries (47.5%) and was characterized by severe HS. SECQ2W and SECQ4W demonstrated efficacy versus placebo in all clusters at week 16; SECQ2W and SECQ4W efficacy was maintained to week 52. SECQ2W treatment showed a trend for greater efficacy versus SECQ4W in Cluster 3 through week 52.

CONCLUSIONS

Three HS clusters were identified. Secukinumab demonstrated benefit over placebo in all clusters. However, patients with more severe disease may take longer to respond and more frequent secukinumab dosing may be required for these patients.

TRIAL REGISTRATION

SUNSHINE (NCT03713619) and SUNRISE (NCT03713632).

Setting the Stage for Standardized Reporting of Clinical and Demographic Information in Laboratory-Based Studies of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a complex inflammatory skin condition affecting 0.1-4% of the population that leads to permanent scarring in the axilla, inframammary region, groin, and buttocks. Its complex pathogenesis involves genetics, innate and adaptive immunity, microbiota, and environmental stimuli. Specific populations have a higher incidence of HS, including females and Black individuals and those with associated comorbidities. HS registries and biobanks have set standards for the documentation of clinical data in the context of clinical trials and outcomes research, but collection, documentation, and reporting of these important clinical and demographic variables are uncommon in HS laboratory research studies. Standardization in the laboratory setting is needed because it helps to elucidate the factors that contribute mechanistically to HS symptoms and pathophysiology. The purpose of this article is to begin to set the stage for standardized reporting in the laboratory setting. We discuss how clinical guidelines can inform laboratory research studies, and we highlight what additional information is necessary for the use of samples in the wet laboratory and interpretation of associated mechanistic data. Through standardized data collection and reporting, data harmonization between research studies will transform our understanding of HS and lead to novel discoveries that will positively impact patient care.

Adopting adalimumab combined surgery in the management of moderate to severe hidradenitis suppurativa: Experience from a single medical center in southern Taiwan

Hidradenitis suppurativa (HS) is a chronic inflammatory disorder primarily affecting the intertriginous and anogenital regions. Guidelines recommend various treatments for HS, including biologic agents like adalimumab for moderate to severe cases. Adalimumab is a type of human monoclonal IgG1 antibody designed to target tumor necrosis factor α. Recent studies have shown the effectiveness of adalimumab, either alone or combined with surgery, in managing HS. We retrospectively analyzed the medical chart of HS patients in a southern Taiwan medical center from 2019 to 2022 and investigated clinical features and treatment response. The institutional review board at Chang Gung Medical Foundation granted approval for the study. We primarily focused on moderate to severely affected patients. One hundred and two clinically diagnosed HS patients participated, with a male-to-female ratio of 2:1 and an average age of 31.8 at diagnosis. Among them, 41.2% were in Hurley stage III and 32.4% in stage II. Nineteen patients received excision with pre-surgical adalimumab; their average age at diagnosis was 31.1, with a gender ratio of 5.3:1. Surgery was most common on the buttocks (68%), axillae (21%), and groin (10%). Excision patients were primarily in advanced stages (Hurley III 94.7%, II 5.3%) with high body mass index. Adalimumab and surgery combined yielded a 68.4% improvement rate, while 15.8% remained stable and 15.8% did not respond as expected. In addition, smoking and obesity were prevalent among patients. Adalimumab showed promising results in moderate to severe HS, with significant improvement observed in our cases. The combination of adalimumab and surgery appeared effective in advanced HS patients with larger involved areas and more tunnels. No severe adverse events were reported. However, our study was limited by its retrospective nature and the lack of a control group. Despite these limitations, our study revealed the benefits of integrating adalimumab with suitable surgical procedures in managing patients experiencing moderate to severe HS in real-world scenarios.

Comorbidities, Clinical Presentation, Subtypes, and Treatment of HS Patients in Lithuania

Background: Hidradenitis suppurativa (HS) is a persistent, recurring skin inflammatory condition linked to various comorbidities. Management involves antibiotics, hormone therapy, immune-modulating drugs, surgery, and treatment of comorbidities. The objectives of the study were to assess the comorbidities, clinical presentation subtypes, and applied treatment of patients with HS. Methods: Patients with HS who visited the Centre of Dermatovenereology at Vilnius University Hospital Santaros Klinikos in Lithuania underwent evaluation based on the guidelines of the European Hidradenitis Suppurativa Foundation Registry questionnaire. Results: The study included 49 patients, and 61.22% (n = 30) had comorbidities. A strong positive correlation was found between a family history of inflammatory diseases (69.38% (n = 34)) and the severity of HS according to Hurley stage (r = 0.71 p < 0.05). A statistically significant correlation (r = 0.944, p = 0.02) was found between metabolic comorbidities and Hurley stage. Patients on biologic treatment had a mean IHS4 of 7.38 at the beginning of treatment and 3.22 at follow-up (p < 0.05). For patients not on biologics, the initial IHS4 score was 6.21 and 5.42 at follow-up (p > 0.05). Conclusions: A family history of inflammatory diseases and metabolic comorbidities showed a strong correlation with HS severity. Treatment with biologics showed significant improvement in HS scores compared to systemic antibiotics.

Deregulated Long Non-Coding RNAs (lncRNA) as Promising Biomarkers in Hidradenitis Suppurativa

Background/Objectives: In recent times, epigenetics alterations in Hidradenitis suppurativa (HS) have been explored and exploited translationally to guide investigation of new therapeutic approaches. On the other hand, long noncoding RNAs (LncRNAs), main regulators of the epigenetic status of the human genome, have been scarcely investigated, notwithstanding their potential relevance in broad pathogenesis comprehension. Here, we aim to explore the methylation pattern of lncRNAs in HS. Methods: In this case-control study, 24 HS patients and age-, sex- and BMI-matched controls were analyzed to characterize the methylome of lncRNA genes in peripheral blood cells. Gene ontology analysis (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, protein-protein interaction (PPI) network, and MCODE analysis were performed. Results: A set of fifteen lncRNA genes exhibited significantly differential methylation patterns, with ten of them showing hypomethylation and five displaying hypermethylation at specific CpG sites. The hypomethylated lncRNA genes were DLEU2, MESTIT1, CASC2, TUG1, KCNQ1DN, PSORS1C3, PCA3, DSCR8, RFPL1S, and PVT1, while the hypermethylated ones were HAR1A, FAM66B, SNHG9, HCG9, and HCP5. These lncRNA genes have been linked to various important biological processes, including cell proliferation, apoptosis, inflammation, chronic inflammatory skin diseases, and wound healing. Their altered methylation status suggests potential roles in regulating these processes, and may contribute to HS pathogenesis and healing mechanisms. Conclusions: This study revealed an interesting dysregulation pattern of definite lncRNAs in the methylome which is linked to both the development of HS and its comorbidities. Epigenetically altered lncRNAs genes could represent useful biomarkers, and could help in guiding innovative treatment strategies.

Belgian Patients of the European Registry for Hidradenitis Suppurativa (ERHS-Be): Data, Scores, and Phenotypes since 2015

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease, characterized by painful and recurrent lesions in apocrine gland-bearing skin areas. It is a heterogeneous disease, which makes assessment and data collection difficult. Questionnaires with detailed items, such as the Belgian European Registry for Hidradenitis Suppurativa (ERHS-Be), are useful to study HS and its associated comorbidities. The aim of this registry was to uncover new factors associated with HS and understand HS patients' clinical profiles and efficacy of treatments.

MATERIAL AND METHODS

The ERHS-Be registry is based on questionnaires, with sections for sociodemographic data, medical and HS history, clinical examination, and treatment plan. It allows identification of different clinical phenotypes and automatic calculation of severity scores.

RESULTS

At present, 606 patients are included in the ERHS-Be (67% women, 33% men). The mean age at the first visit is 38.5 years. Tobacco use is present in 72.6% of patients. A family history of HS is noted in 42% of patients. Comorbidities are documented in this cohort: depression is present in 43.8% of patients, arthritis in 27.8%, obesity in 31.5%, hypertension in 10.6%, diabetes mellitus in 6.4%, and dyslipidemia in 12.4%. Moreover, 7.7% of patients suffer from IBD and 27.4% have a pilonidal sinus. History of severe acne is found in 32.1% of patients and psoriasis in 9.3%. Thirteen percent of women in our cohort suffer from polycystic ovarian syndrome. Severity of disease is quantified in 533 patients: for instance, Hurley I, II, and III scores proportions are, respectively, 32.3%, 52.7%, and 15%, while the mean IHS4 score is 5.2. This registry also enables determination of relative phenotype proportions in our cohort, according to different classifications.

CONCLUSION

The ERHS-Be questionnaires allow systematic and larger data collection, including detailed comorbidities, phenotypes, and severity of disease. Analysis of this large database will contribute to a better understanding and management of HS, at a time where new therapeutic options are becoming available.

Differences in hidradenitis suppurativa patterns of cutaneous involvement between sexes: Insights from a cross-sectional study

Hidradenitis suppurativa is a chronic, inflammatory condition of the pilosebaceous unit in which patients manifest multiple, painful cutaneous nodules, abscesses and tunnels. These lesions are described to affect the intertriginous zones, however, the condition exhibits significant phenotypic variability. Such variability is influenced by the patients lifestyle, genetic predisposition and sex. In this cross-sectional study, we investigate sex differences in patterns of hidradenitis suppurativa skin involvement, specifically at site of first involvement and most bothersome cutaneous site of involvement.

[Hidradenitis suppurativa]

Hidradenitis suppurativa (HS) is a chronic and debilitating inflammatory disease derived from the pilosebaceous unit, that affects approximately 1% of the general population. Clinically, it is characterized by inflammatory nodules, abscesses, and tunnels in the intertriginous areas of the body, especially in the axillary, inguinal, and anogenital regions. The etiopathogenesis of HS is not completely understood, although it is considered to be multifactorial, and the result of a complex interaction between genetic, hormonal, environmental, and immunological factors. In this sense, several proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-L-1β, and IL-17, among others, appear to play a crucial role in the pathogenesis of the disease. Currently, HS is recognized as a systemic disease associated with numerous comorbidities, including cardiovascular, immune-mediated, and endocrine-metabolic diseases. The treatment of HS must be carried out with an individualized and patient-oriented approach, considering medical and surgical treatment modalities.

Hidradenitis suppurativa associated telomere-methylome dysregulations in blood

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic debilitating disease with a significant burden of both organic and psychological comorbidities. It has been shown that certain telomere-related genes (TRGs) affect a wide range of diseases, including HS and its associated comorbidities, but their exact role in HS pathogenesis is still unknown.

OBJECTIVES

To determine whether TRG methylomes can be used as biomarkers in HS.

METHODS

Using the Illumina HumanMethylation450 BeadChip array, we examined methylation variations associated with TRGs in HS cases and age-, sex- and ethnicity-matched healthy controls. The study utilized integrated bioinformatics statistical methods, such as a false discovery rate (FDR), the area under the receiver operating characteristic curve (AUC) and principal component analysis.

RESULTS

There were a total of 585 different differentially methylated CpG sites identified in 585 TRGs associated with HS (474 hypomethylated and 111 hypermethylated) (FDR p-value < 0.05). A number of these CpGs have been identified as being involved in increased pain sensitivity including EPAS1, AHR, CSNK1D, DNMT1, IKBKAP, NOS3, PLCB1 and PRDM16 genes; GABRB3 as a potential alcohol addiction marker; DDB1, NSMCE2 and HNRNPA2B1 associated with cancers. Pathway analysis identified 67 statistically significant pathways, including DNA repair, telomere maintenance, mismatch repair and cell cycle control (p < 0.001).

CONCLUSION

The disruption of TRGs leads to the shortening of telomeres, which is associated with HS progression, ageing, cellular senescence and an increased risk of various diseases, including cancer and associated comorbidities, such as metabolic syndrome, cardiovascular disease and inflammatory disorders. Further research is necessary to better understand the underlying mechanisms and establish causal links between TRGs and HS. The present study is the first effort to comprehend potential pathomechanisms of sporadic HS cases concentrating on PBMC methylome since ours.

Gluteal Hidradenitis Suppurativa: Analysis of 83 Patients

BACKGROUND

In 2013, Canoui-Poitrine et al. identified three hidradenitis suppurativa (HS) phenotypes by a latent class (LC) analysis, based on anatomical sites of involvement.

OBJECTIVE

To improve the classification of the gluteal phenotype (LC3) patients given their diverse lesion types and differences in clinical profile.

MATERIAL AND METHODS

We designed a bicentric study gathering all LC3 patients (n=83) from two hospitals. We conducted a two-step cluster analysis among them and also compared their characteristics with the rest of the HS patients (n=661).

RESULTS

Compared with global HS series, LC3 patients were more frequently non-obese men, with smoking habit, an associated arthropathy, and a more frequent history of pilonidal sinus. The analysis of LC3 patients yielded two clusters: cluster 1 (38.3%) included elderly female patients, with later diagnosis of the disease and more sinus tracts; cluster 2 (61.7%) encompassed more men with earlier disease onset and more nodules and folliculitis lesions.

LIMITATIONS

The study's limitations include its retrospective nature, bicentric design, and small sample size.

CONCLUSION

The heterogeneous clinical presentation of HS makes it essential to have a good classification of the patients. Gluteal phenotype could actually be classified into two "subphenotypes" with a different clinical profiles and management.

Gluteal Hidradenitis Suppurativa: Analysis of 83 Patients

BACKGROUND

In 2013, Canoui-Poitrine et al. identified three hidradenitis suppurativa (HS) phenotypes by a latent class (LC) analysis, based on anatomical sites of involvement.

OBJECTIVE

To improve the classification of the gluteal phenotype (LC3) patients given their diverse lesion types and differences in clinical profile.

MATERIAL AND METHODS

We designed a bicentric study gathering all LC3 patients (n=83) from two hospitals. We conducted a two-step cluster analysis among them and also compared their characteristics with the rest of the HS patients (n=661).

RESULTS

Compared with global HS series, LC3 patients were more frequently non-obese men, with smoking habit, an associated arthropathy, and a more frequent history of pilonidal sinus. The analysis of LC3 patients yielded two clusters: cluster 1 (38.3%) included elderly female patients, with later diagnosis of the disease and more sinus tracts; cluster 2 (61.7%) encompassed more men with earlier disease onset and more nodules and folliculitis lesions.

LIMITATIONS

The study's limitations include its retrospective nature, bicentric design, and small sample size.

CONCLUSION

The heterogeneous clinical presentation of HS makes it essential to have a good classification of the patients. Gluteal phenotype could actually be classified into two "subphenotypes" with a different clinical profiles and management.

Hidradenitis suppurativa: new insights into disease mechanisms and an evolving treatment landscape

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic disabling and debilitating inflammatory disease with a high unmet medical need. The prevalence of HS reported in most studies is 1-2%, although it is likely to be under-reported and estimates vary globally owing to variance in data collection methods, ethnicity, geographical location and under-diagnosis. HS is characterized by persistent, painful cutaneous nodules, abscesses and draining tunnels commonly affecting the axillary, anogenital, inguinal and perianal/gluteal areas. Over time, chronic uncontrolled inflammation results in irreversible tissue destruction and scarring. Although the pathophysiology of HS has not been fully elucidated, the tumour necrosis factor (TNF)-α and interleukin (IL)-17 pathways have an important role, involving multiple cytokines. Currently, treatment options include topical medications; systemic therapies, including repeated and/or rotational courses of systemic antibiotics, retinoids and hormonal therapies; and various surgical procedures. The anti-TNF-α antibody adalimumab is currently the only biologic approved by both the US Food and Drug Administration and the European Medicines Agency for HS; however, its efficacy varies, with a clinical response reported in approximately 50% of patients in phase III trials. HS is a rapidly evolving field of discovery, with a diverse range of agents with distinct mechanisms of action currently being explored in clinical trials. Several other promising therapeutic targets have recently emerged, and agents targeting the IL-17 and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways are the most advanced in ongoing or completed phase III clinical trials. Alongside limited therapeutic options, significant challenges remain in terms of diagnosis and disease management, with a need for better treatment outcomes. Other unmet needs include significant diagnostic delays, thus missing the therapeutic 'window of opportunity'; the lack of standardized outcome measures in clinical trials; and the lack of established, well-defined disease phenotypes and biomarkers.

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.

Clinical Features and Response to Treatment in Elderly Subjects Affected by Hidradenitis Suppurativa: A Cohort Study

Hidradenitis suppurativa (HS) is a chronic-relapsing inflammatory skin disease. It usually appears in the second and third decades, but a smaller proportion of patients develop late-onset HS. Geriatric HS, defined as the persistence or the development of HS after the age of 65 years, has been poorly explored. This study aimed to investigate the clinical features, treatment management and response to therapies of HS elderly subjects (≥65 years old). We designed a multicentric observational study, gathering data from seven Italian university hospitals. Demographic and clinical data of HS patients aged over 65 years were collected at baseline, week 12 and week 24. Overall, 57 elderly subjects suffering from HS were enrolled. At baseline, disease severity was predominantly moderate-to-severe, with 45.6% of patients classified as Hurley III. The gluteal phenotype was the most frequently observed; it also appeared to affect patients' quality of life more than other phenotypes. Gluteal involvement was detected in about half (49.1%) of cases and associated with severe stages of the disease. In terms of therapeutic response, Hurley III patients showed the persistency of higher values of mean IHS4, DLQI, itch- and pain-NRS scores compared to Hurley I/II. In conclusion, disease severity in this subpopulation appears high and treatment is often challenging.

What should a surgeon know about hidradenitis suppurativa?

Otherwise known as Verneuil's disease, hidradenitis suppurative (HS) is a severe dermatosis of heterogeneous appearance affecting 1% of the population. Its pathophysiology is multifactorial, involving genetic predisposition, inflammatory disorder and environmental elements. Its diagnosis is based on the association of three clinical characteristics: characteristic lesions, typical localizations, and the chronic and recurrent nature of the lesions. Given its diversified aspects, diagnosis can be difficult to achieve. As its manifestations often include abscesses, it is important for the surgeon to know how to detect this pathology. The development of biologics has improved treatment of this disease, treatment that necessitates a multidisciplinary medical and surgical approach involving dermatologists and proctologists as well as surgeons. The objective of this report is to synthesize what a surgeon will need to know so as effectively treat HS patients.

A loss-of-function NCSTN mutation associated with familial Dowling Degos disease and hidradenitis suppurativa

Dowling Degos disease (DDD) is a rare autosomal dominant genodermatosis characterized by acquired, slowly progressive reticulated pigmented lesions primarily involving flexural skin areas. Mutations in KRT5, POGLUT-1 and POFUT-1 genes have been associated with DDD, and loss-of-function mutations in PSENEN, a subunit of the gamma-secretase complex, were found in patients presenting with DDD or DDD comorbid with hidradenitis suppurativa (HS). A nonsense mutation in NCSTN, another subunit of the gamma-secretase, was already described in a patient suffering from HS and DDD but whether NCSTN could be considered a novel gene for DDD is still debated. Here, we enrolled a four-generation family with HS and DDD. Through Whole Exome Sequencing (WES) we identified a novel nonsense mutation in the NCSTN gene in all the affected family members. To study the impact of this variant, we isolated outer root sheath cells from patients' hair follicles. We showed that this variant leads to a premature stop codon, activates a nonsense-mediated mRNA decay, and causes NCSTN haploinsufficiency in affected individuals. In fact, cells treated with gentamicin, a readthrough agent, had the NCSTN levels corrected. Moreover, we observed that this haploinsufficiency also affects other subunits of the gamma-secretase complex, possibly causing DDD. Our findings clearly support NCSTN as a novel DDD gene and suggest carefully investigating this co-occurrence in HS patients carrying a mutation in the NCSTN gene.

Hidradenitis suppurativa from the typical patient to the new clinical phenotypes

Hidradenitis suppurativa (HS) is a clinically heterogeneous disease with a broad spectrum of clinical features. Attempts to classify HS into distinct clinical phenotypes could lead to a better understanding of the condition and the development of individualized treatment protocols. We summarize some of the existing phenotype classifications and present our experience with 250 patients and their many clinical presentations. We have emphasized the pathophysiologic and clinical overlap between HS and pyoderma gangrenosum. The more severe presentations can include erosive and ulcerative lesions, sometimes associated with vegetative changes leading to diagnostic quandaries. We propose a new phenotype of pyoderma gangrenosum-like HS in which painful ulcerative or vegetative lesions appear in sites affected by HS, their activity coincides with the flareups of classic inflammatory manifestations of HS, and they heal with cribriform or atrophic scars.

Epidemiology of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent skin disease affecting hair follicles in predominantly intertriginous areas, characterized by deep, painful nodules and abscesses, fistulas, sinus tracts, and scarring. The estimated global prevalence of HS is highly variable, as revealed in a growing body of published literature, and ranges from 0.053% to 4.1%. In North American and European patients, HS is three times more common in women than men, whereas in South Korea and Japan, male predominance is found. The disease most frequently manifests itself between the ages of 18 and 29. Numerous published studies have reported the association between smoking, obesity, and HS, although there are limitations in confirming the causal relationship due to the retrospective design of the available studies. Case-control studies have frequently evaluated the association between HS, metabolic syndrome, and other systemic comorbidities. Due to increased mental health problems, a higher risk of suicide in patients with HS has been reported. We provide up-to-date evidence about the epidemiology, genetic and environmental risk factors, comorbidities, and quality of life of patients with HS. The divergence in HS frequency, possibly due to differences in populations and methodologies, remains to be explained in future worldwide studies.

Assessment tools and phenotype classification for hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a heterogeneous chronic relapsing skin disease. Several assessment tools are used to assess disease severity and to classify disease phenotype; however, no consensus exists. This review evaluates the various assessment tools and phenotypes, assessing their validity and reliability. Numerous assessment tools and phenotype classifications have been proposed for identifying various subtypes within the hidradenitis suppurativa disease spectrum. Each has a different purpose, such as use in daily practice or in clinical trial settings. Several assessment tools and phenotype classifications have been validated but not always with satisfactory results and often with studies showing divergent intra-rater reliability results. A consensus is needed for a validated, easy-to-use, and timesaving assessment tool for routine daily practice. For clinical trials, a validated and extensive assessment tool that also measures response to treatment is also needed.

Genetic Variants Associated With Hidradenitis Suppurativa

Importance

Hidradenitis suppurativa (HS) is a common and severely morbid chronic inflammatory skin disease that is reported to be highly heritable. However, the genetic understanding of HS is insufficient, and limited genome-wide association studies (GWASs) have been performed for HS, which have not identified significant risk loci.

Objective

To identify genetic variants associated with HS and to shed light on the underlying genes and genetic mechanisms.

Design, Setting, and Participants

This genetic association study recruited 753 patients with HS in the HS Program for Research and Care Excellence (HS ProCARE) at the University of North Carolina Department of Dermatology from August 2018 to July 2021. A GWAS was performed for 720 patients (after quality control) with controls from the Add Health study and then meta-analyzed with 2 large biobanks, UK Biobank (247 cases) and FinnGen (673 cases). Variants at 3 loci were tested for replication in the BioVU biobank (290 cases). Data analysis was performed from September 2021 to December 2022.

Main Outcomes and Measures

Main outcome measures are loci identified, with association of P < 1 × 10-8 considered significant.

Results

A total of 753 patients were recruited, with 720 included in the analysis. Mean (SD) age at symptom onset was 20.3 (10.57) years and at enrollment was 35.3 (13.52) years; 360 (50.0%) patients were Black, and 575 (79.7%) were female. In a meta-analysis of the 4 studies, 2 HS-associated loci were identified and replicated, with lead variants rs10512572 (P = 2.3 × 10-11) and rs17090189 (P = 2.1 × 10-8) near the SOX9 and KLF5 genes, respectively. Variants at these loci are located in enhancer regulatory elements detected in skin tissue.

Conclusions and Relevance

In this genetic association study, common variants associated with HS located near the SOX9 and KLF5 genes were associated with risk of HS. These or other nearby genes may be associated with genetic risk of disease and the development of clinical features, such as cysts, comedones, and inflammatory tunnels, that are unique to HS. New insights into disease pathogenesis related to these genes may help predict disease progression and novel treatment approaches in the future.

Obesity and hidradenitis suppurativa: targeting meta-inflammation for therapeutic gain

Hidradenitis suppurativa (HS) is a chronic, inflammatory condition of the pilosebaceous unit. The typical patient with HS is characterized as someone with obesity, who smokes and who has nodules, abscesses and/or draining tunnels predominantly distributed in intertriginous skin. It has been established that lifestyle and genetic factors are the main pathophysiological drivers of HS. In this critical review, we explore the interrelatedness of meta-inflammation, obesity and HS and discuss if and how this relationship may be manipulated for a therapeutic end.

Worst area local Hidradenitis suppurativa Activity and Severity Index-Revised (W-HASI-R): a study evaluating construct validity

Current validated hidradenitis suppurativa (HS) severity assessment tools are time-consuming and impractical in fast-paced, ambulatory clinic settings. This study evaluated the construct validity of the most severe or ‘worst’ area local Hidradenitis suppurativa Activity and Severity Index-Revised (W-HASI-R) as a novel target area assessment tool for clinical setting use. W-HASI-R had strong association with the International Hidradenitis Suppurativa Severity Score System and abscess and nodule count, moderate association with Hurley stage and HS physician global assessment and weak, negative association with reverse-scored Dermatology Quality Life Index. The resulting data suggest that W-HASI-R may be an option as an efficient target area assessment tool for fast-paced, ambulatory settings.

Treatment of Acne with Isotretinoin Should Be Avoided in Patients with Hidradenitis Suppurativa "Conglobata Phenotype"

BACKGROUND

Acne conglobata (AC) and nodulocystic acne have long been confused clinically, despite the presentation and the response to treatment being different. AC and hidradenitis suppurativa (HS) resemble each other; a subtype of HS called "conglobata phenotype" has recently been reported in a large Dutch cohort. Acne vulgaris and HS are often associated. Isotretinoin is typically ineffective in treating HS and may even aggravate it, but it is often indispensable in treating acne vulgaris.

OBJECTIVE

The aim of the study was to assess whether isotretinoin may be used safely in adults with both HS and acne vulgaris and when it might be contraindicated.

MATERIALS AND METHODS

Belgian HS patients from the European Registry for Hidradenitis Suppurativa Registry (ERHS) reporting a history of severe acne of the face and/or the back, and who have ever used isotretinoin for their acne, were all selected. Patients whose acne worsened on isotretinoin were compared to patients whose acne did not worsen (improvement or no change).

RESULTS

Among the 82 selected patients, 10 (12.2%) report that their acne was aggravated while taking isotretinoin, while 72 (87.8%) report that their acne was not aggravated on isotretinoin. Of the 10 HS patients whose acne worsened with isotretinoin, 9 (90%) were men (p = 0.04) and 8 (80%) were HS "conglobata phenotype" (p < 0.001). In contrast, 47 (65.3%) of the 72 patients whose acne did not worsen on isotretinoin belonged to the HS "regular phenotype" (p = 0.01). On multivariate analysis, the item most strongly associated with poor response to isotretinoin was the HS "conglobata phenotype," followed by body mass index (BMI) (worse response to isotretinoin if BMI >25 kg/m2). Additionally, of 26 patients who received isotretinoin while their HS had already started, only 6 (23.1%) reported isotretinoin effectiveness on their HS.

CONCLUSION

Subject to confirmation by larger studies, our study suggests that isotretinoin should be avoided in the treatment of acne in HS patients with the HS "conglobata phenotype," as it may worsen the acne, likewise being male or having a BMI above 25 seems to increase this risk of a bad therapeutic outcome. Patients with an HS "regular phenotype" appear to be at a reduced risk of isotretinoin treatment worsening their acne.

New Insight into the Molecular Pathomechanism and Immunomodulatory Treatments of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is an immune-mediated inflammatory disorder characterized by deep-seated nodules, abscesses, sinus tracts and scars localized in the intertriginous areas. It is accompanied by pain, malodourous secretion and a dramatically decreased quality of life. Although the pathogenesis has not been entirely elucidated, the primary event is follicular hyperkeratosis of the pilosebaceous apocrine unit. Since the registration of the tumor necrosis factor-alpha inhibitor Adalimumab in 2015, several cytokines have been implicated in the pathomechanism of HS and the research of novel therapeutic targets has been intensified. We provide an update on the inflammatory cytokines with a central role in HS pathogenesis and the most promising target molecules of future HS management.

Metformin Treatment of Hidradenitis Suppurativa: Effect on Metabolic Parameters, Inflammation, Cardiovascular Risk Biomarkers, and Immune Mediators

Hidradenitis suppurativa (HS) is a common cutaneous and systemic inflammatory disease with a significant impact on mental health and quality of life. It is associated with obesity, insulin resistance, metabolic syndrome, cardiovascular (CV) disease, and increased all-cause mortality. Metformin is used frequently in HS treatment and is effective for some patients. The mechanism of action of metformin in HS is unknown. A case-control study of 40 patients with HS (20 on metformin and 20 controls) was conducted to assess differences in metabolic markers, inflammation (C-reactive protein [CRP], serum adipokines, and CV risk biomarkers), and serum immune mediators. Body mass index (BMI), insulin resistance (77%), and metabolic syndrome (44%) were high overall, but not significantly different between the groups. This highlights the need for co-morbidity screening and management. A significant reduction in fasting insulin and a trend towards a reduction in insulin resistance were identified in the metformin group compared with pre-treatment levels. CV risk biomarkers were significantly favourable in the metformin group (lymphocytes, monocyte-lymphocyte ratio, neutrophil-lymphocyte ratio, and platelet-lymphocyte ratio). CRP was lower in the metformin group but was not statistically significant. Adipokines were dysregulated overall but were not different between the two groups. Serum IFN-γ, IL-8, TNF-α, and CXCL1 trended lower in the metformin group but did not reach significance. These results suggest that metformin improves CV risk biomarkers and insulin resistance in patients with HS. When the results of this study are considered alongside other studies in HS and related conditions, it is likely that metformin also has beneficial effects on metabolic markers and systemic inflammation in HS (CRP, serum adipokines, and immune mediators), warranting further research.

Management of patients with hidradenitis suppurativa having underlying genetic variation: a systematic review and a call for precision medicine

Hidradenitis suppurativa (HS) is a chronic inflammatory condition of the pilosebaceous unit characterized by inflammation and hyperkeratinization. A small but significant proportion of patients with HS have a strong genetic susceptibility to (or a syndromic form of) the disease. Current HS treatment guidelines prioritize patients who manifest classic HS and may therefore not be suitable for the minority of patients harbouring genetically driven forms of disease. In this manuscript, we review the extant literature with regards to therapeutic strategies used for patients with HS having disease-associated genetic variants and syndromic forms of the condition. The findings of this review suggest that patients with HS harbouring underlying genetic variants may not be adequately represented in current European and British HS treatment guidelines. Moreover, these patients may be less responsive to the recommended therapeutic options. We therefore make recommendations for future therapeutic guidelines to incorporate considerations for the management of this patient subset.

Can hidradenitis suppurativa patients classify their lesions by means of a digital lesion identification scheme?

BACKGROUND AND OBJECTIVES

Hidradenitis suppurativa (HS) differs widely with respect to its clinical presentation. Literature imposes different phenotypes potentially implying different treatment modalities. The aim of this study is to develop a validated scheme that enables HS patients to identify their own lesion types.

PATIENTS AND METHODS

The developed schemes for physicians and patients were implemented in a specific software. Upon patient consent, the physician used the software to document the lesions identified. Patients subsequently logged into the patient-version of the software from the convenience of their home and selected the lesions they identified on themselves. Afterwards the correlation between professionals and patients was tested.

RESULTS

For seven lesion types, correlation coefficients were statistically significant. A large/strong correlation between patients and physicians was found for the draining fistulas (0.59) and double-ended comedones (0.50). For five other lesion types, correlation was medium/moderate, namely the inflammatory nodule (0.37), abscess (0.30), accordion like-/ bridged scar (0.45), epidermal cyst (0.33) and pilonidal sinus (0.39).

CONCLUSIONS

HS-patients demonstrate high willingness to share their experiences and data. Therefore, a self-assessment scheme, as the developed LISAI, can be a valuable tool to enrich patient surveys with the identification of lesion types, for instance as a basis for phenotyping.

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.

A cross-sectional study of pediatric hidradenitis suppurativa and the value of the International Hidradenitis Suppurativa Severity Score System (IHS4) as a pediatric clinical trial inclusion criteria

BACKGROUND

Hidradenitis suppurativa (HS) often develops in pediatrics, but few interventional studies include pediatric patients.

OBJECTIVES

This dual analysis of a pediatric HS cohort and typical eligibility criteria in adult trials aims to identify potential patient characteristics and inclusion criteria for future pediatric HS studies.

METHODS

This cross-sectional and descriptive study is based on a prospectively collected data registry from an HS clinic. We also queried 125 HS studies from the Clinicaltrials.gov database and information from 61 interventional systemic HS drug trials was analyzed.

RESULTS

The mean abscess and inflammatory nodule (AN) count in 81 pediatric subjects was 2.3 compared to 5.0 in adults with majority being Hurley stage I (39.5%, 32/81) or II (55.6%, 45/81). Most clinical trials required patients to be Hurley stage II/III with AN count of ≥3.

CONCLUSION

When developing clinical trials for pediatric HS, it is imperative to consider how baseline characteristics impact recruitment and disease assessment. Frequently used eligibility criteria in adult trials may severely limit pediatric recruitment. Although our registry had a large adult sample size, the main limitation of this study was the relatively smaller pediatric sample size.

Hidradenitis Suppurativa: A Perspective on Genetic Factors Involved in the Disease

Hidradenitis Suppurativa (HS) is a chronic inflammatory skin disease of the pilosebaceous unit, clinically consisting of painful nodules, abscesses, and sinus tracts mostly in, but not limited to, intertriginous skin areas. HS can be defined as a complex skin disease with multifactorial etiologies, including—among others—genetic, immunologic, epigenetic, and environmental factors. Based on genetic heterogeneity and complexity, three different forms can be recognized and considered separately as sporadic, familial, and syndromic. To date, several genetic variants associated to disease susceptibility, disease-onset, and/or treatment response have been reported; some of these reside in genes encoding the gamma-secretase subunits whereas others involve autoinflammatory and/or keratinization genes. The aim of this perspective work is to provide an overview of the contribution of several genetic studies encompassing family linkage analyses, target candidate gene studies, and -omic studies in this field. In our viewpoint, we discuss the role of genetics in Hidradenitis suppurativa considering findings based on Sanger sequencing as well as the more recent Next Generation Sequencing (i.e., exome sequencing or RNA Sequencing) with the aim of better understanding the etio-pathogenesis of the disease as well as identifying novel therapeutic strategies.

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.

Similar Levels of Efficacy of Two Different Maintenance Doses of Adalimumab on Clinical Severity and Quality of Life of Patients with Hidradenitis Suppurativa

Adalimumab is the only biologic agent approved for the treatment of moderate-to-severe hidradenitis suppurativa (HS) patients (i.e., with Hurley II or III), which is recommended in two different maintenance doses (i.e., 40 mg weekly or 80 mg every two weeks). We conducted a prospective multicentric study to measure outcomes related to the severity of disease and quality of life (QoL) of patients affected by moderate-to-severe HS, treated with adalimumab at a maintenance dosing of 40 mg or 80 mg. Assessments were performed at baseline (T0) and after 32 weeks of treatment (T32). We enrolled 85 moderate-to-severe HS Italian patients, 43 men (50.6%) and 42 women, aged between 16 and 62 years (median 31 years, interquartile range 24.4–43.8). Statistically significant improvements were observed for clinical status (with a mean reduction of 7.1 points for the International Hidradenitis Suppurativa Severity Score System (IHS4)), pain levels (3.1 mean decrease in VAS), and QoL (3.4 mean improvement in DLQI score). Patients with no comorbidities, and those with higher levels of perceived pain showed significantly greater improvement in QoL than their counterpart from T0 to T32. As for the proportion of patients who at follow-up reached the minimal clinical important difference (MCID) in QoL, significantly higher proportions of success were observed for age (patients in the 29–39 category), pain (patients with higher reported pain), and Hurley stage III. While both treatment regimen groups (i.e., 40 vs. 80 mg) improved significantly, no statistical differences were observed when comparing the two treatment dosages.

Holistic health record for Hidradenitis suppurativa patients

Hidradenitis suppurativa (HS) is a recurrent inflammatory skin disease with a complex etiopathogenesis whose treatment poses a challenge in the clinical practice. Here, we present a novel integrated pipeline produced by the European consortium BATMAN (Biomolecular Analysis for Tailored Medicine in Acne iNversa) aimed at investigating the molecular pathways involved in HS by developing new diagnosis algorithms and building cellular models to pave the way for personalized treatments. The objectives of our european Consortium are the following: (1) identify genetic variants and alterations in biological pathways associated with HS susceptibility, severity and response to treatment; (2) design in vitro two-dimensional epithelial cell and tri-dimensional skin models to unravel the HS molecular mechanisms; and (3) produce holistic health records HHR to complement medical observations by developing a smartphone application to monitor patients remotely. Dermatologists, geneticists, immunologists, molecular cell biologists, and computer science experts constitute the BATMAN consortium. Using a highly integrated approach, the BATMAN international team will identify novel biomarkers for HS diagnosis and generate new biological and technological tools to be used by the clinical community to assess HS severity, choose the most suitable therapy and follow the outcome.

Insights into hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, debilitating, inflammatory skin disorder with a prevalence of around 1% and a profound impact on patients' quality of life. Characteristic lesions such as inflammatory nodules, abscesses, and sinus tracts develop in the axillae, inguinal, and gluteal areas, typically during or after puberty. A complex interplay of genetic predisposition, hormonal factors, obesity, and smoking contributes to development and maintenance of the disease. HS is considered to arise from an intrinsic defect within the hair follicle, leading to follicular plugging, cyst formation, and subsequent rupture that in turn induce an acute inflammatory response characterized by elevated levels of IL-1β, IL-17, and TNF. Over time, acute lesions transition into chronic disease, with active draining sinus tracts accompanied by extensive fibrosis. HS is associated with other immune-mediated inflammatory diseases, metabolic and cardiovascular disorders, and psychiatric comorbidities. Treatment of HS often requires a combination of antibiotic or immunosuppressing therapies and surgical intervention. Nonetheless, the currently available treatments are not universally effective, and many drugs, which are often repurposed from other inflammatory diseases, are under investigation. Studies into the early stages of HS may yield treatments to prevent disease progression; yet, they are hampered by a lack of appropriate in vitro and animal models.

New and Emerging Targeted Therapies for Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory skin disease deriving from the hair follicles. The formation of inflammatory nodules, abscesses, fistulas, and sinus tracts is characterized by a large inflow of key pro-inflammatory mediators, such as IFN-γ, TNF-α, IL-1, IL-17, and IL-12/23. Adalimumab is currently the only Food and Drug Administration (FDA)- and European Medicines Agency (EMA)-approved biologic therapy for moderate to severe HS in adults and adolescents. However, the long-term effectiveness of this TNF-α inhibitor in HS patients has shown to be highly variable. This review aims to review the evidence for emerging therapies that target the main pro-inflammatory cytokines in HS pathogenesis. A review of the literature was conducted, using the PubMed and Google Scholar repositories, as well as Clinicaltrials.gov. Presently, the most promising biologics in phase III trials are anti-IL-17 antibodies, secukinumab, and bimekizumab. Furthermore, an anti-IL-1 biologic, bermekimab, is currently in phase II trials, and shows encouraging results. Overall, the clinical efficacies of all new targeted therapies published up to this point are limited. More studies need to be performed to clarify the precise molecular pathology, and assess the efficacy of biological therapies for HS.

Hidradenitis Suppurativa: morphologic and vascular study of nodular inflammatory lesions by means of optical coherence tomography

BACKGROUND

Hidradenitis Suppurativa (HS) is an inflammatory disease characterized by a recurrent-remission trend and clinical lesions that range from asymptomatic to inflamed, deep-seated nodules with scarring and suppuration.

OBJECTIVE

To identify morphologic and vascular features of HS nodules by means of dynamic optical coherence tomography (D-OCT) and to define if they are correlated to patient endotype and risk of disease progression.

METHODS

A set of standardized clinical pictures and D-OCT images were acquired from 57 inflammatory nodules of 40 patients affected by HS. A set of 20 clinical and D-OCT images were acquired from 20 healthy volunteers as a control group. The comparison of D-OCT features among HS and control group was analyzed. The correlation between HS patient endotype and D-OCT features of the lesions was calculated.

RESULTS

D-OCT enabled to identify vascular and morphological aspects characterizing HS nodular inflammatory lesions. In addition, several D-OCT features were significantly different among distinct disease endotypes.

CONCLUSION

The characterization of HS nodular inflammatory lesions through D-OCT, corresponding to blood vessel dilation and inflammatory associated hyper-vascularization, may have important clinical consequences in the assessment of HS risk of progression, therapeutic decisions and treatment efficacy monitoring.

Whole-Exome Sequencing in 10 Unrelated Patients with Syndromic Hidradenitis Suppurativa: A Preliminary Step for a Genotype-Phenotype Correlation

BACKGROUND

The genetics of syndromic hidradenitis suppurativa (HS), an immune-mediated condition associated with systemic comorbidities such as inflammatory bowel diseases and arthritis, has not been completely elucidated.

OBJECTIVE

To describe clinical features and genetic signature of patients with the main syndromic HS forms, i.e., PASH, PAPASH, and PASH/SAPHO overlapping.

METHODS

Whole-exome sequencing (WES) approach was performed in ten patients with syndromic HS.

RESULTS

Three clinical settings have been identified based on presence/absence of gut and joint inflammation. Four PASH patients who had also gut inflammation showed three different variants in NOD2 gene, two variants in OTULIN, and a variant in GJB2, respectively. Three PAPASH and three PASH/SAPHO overlapping patients who had also joint inflammation showed two different variants in NCSTN, one in WDR1 and PSTPIP1, and two variants in NLRC4, one of whom was present in a patient with a mixed phenotype characterized by gut and joint inflammation.

LIMITATIONS

Limited number of patients that can be counterbalanced by the rarity of syndromic HS.

CONCLUSION

Syndromic HS can be considered as a polygenic autoinflammatory condition; currently WES is a diagnostic tool allowing more accurate genotype-phenotype correlation.

Hidradenitis Suppurativa: Where We Are and Where We Are Going

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease primarily affecting apocrine gland-rich areas of the body. It 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. Innate pro-inflammatory cytokines (e.g., IL-1β, and TNF-α); mediators of activated T helper (Th)1 and Th17 cells (e.g., IFN-γ, and IL-17); and effector mechanisms of neutrophilic granulocytes, macrophages, and plasma cells are involved. On the other hand, HS lesions contain anti-inflammatory mediators (e.g., IL-10) and show limited activity of Th22 cells. The inflammatory vicious circle finally results in pain, purulence, tissue destruction, and scarring. HS pathogenesis is still enigmatic, and a valid animal model for HS is currently not available. All these aspects represent a challenge for the development of therapeutic approaches, which are urgently needed for this debilitating disease. Available treatments are limited, mostly off-label, and surgical interventions are often required to achieve remission. In this paper, we provide an overview of the current knowledge surrounding HS, including the diagnosis, pathogenesis, treatments, and existing translational studies.