Hidradenitis Suppurativa: Proposal of Classification in Two Endotypes with Two-Step Cluster Analysis

Surgical Approach to Hidradenitis Suppurativa

Hidradenitis suppurativa is a chronic inflammatory skin condition characterized by painful nodules, abscesses, and sinus tracts that may lead to irreversible scarring complications. Therapeutic options include antibiotics, biologic therapies, and surgical procedures. Current management of hidradenitis suppurativa favors early surgical intervention along with medical therapy to promote healing and minimize scars and complications in a disease characterized by a therapeutic window of opportunity. Surgical techniques range from incision and drainage to wide excision, with varying recurrence rates mainly based on the extent of procedures. Reconstruction techniques would vary primarily based on the extent of the defect and the area involved. In all cases, a good preoperative planning and delimitation with imaging modalities, preferably intra- or perioperative facilitates complete removal of involved tissue, preserving the integrity and function of healthy skin and minimizing recurrences.

Different Phenotypes of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disorder with a heterogeneous phenotype. HS is a recurrent, fluctuating disease with various natural histories. Its phenotypes have been associated with responses to therapy; however, more studies about treatment response are needed, as is evaluation of biomarkers, before conclusions can be reached. This article provides a scoping review of HS phenotypes reported in the literature, with the hope that the results may offer insights for a more individualized approach to treatment.

Surgical Approach to Hidradenitis Suppurativa

Hidradenitis suppurativa is a chronic inflammatory skin condition characterized by painful nodules, abscesses, and sinus tracts that may lead to irreversible scarring complications. Therapeutic options include antibiotics, biologic therapies, and surgical procedures. Current management of hidradenitis suppurativa favors early surgical intervention along with medical therapy to promote healing and minimize scars and complications in a disease characterized by a therapeutic window of opportunity. Surgical techniques range from incision and drainage to wide excision, with varying recurrence rates mainly based on the extent of procedures. Reconstruction techniques would vary primarily based on the extent of the defect and the area involved. In all cases, a good preoperative planning and delimitation with imaging modalities, preferably intra- or perioperative facilitates complete removal of involved tissue, preserving the integrity and function of healthy skin and minimizing recurrences.

A novel scoring system for better management of small bowel obstruction

PURPOSE

Due to the lack of a comprehensive evaluation of the prognosis of small bowel obstruction (SBO), recent clinical strategies have remained subjective and controversial. The recognition of pretreatment risk factors and tailored treatment could improve SBO outcomes.

METHODS

A series of posttreatment laboratory tests were integrated into a two-step clustering (TSC) analysis. The TSC outcome was determined according to different predictor importance (PI). A risk score (RS) system for the TSC outcome model was constructed by multivariable analysis. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were calculated to assess prediction accuracy.

RESULTS

Of the 355 patients, 66 (18.6%) were sorted into the better prognosis group (BPG), 149 (42.0%) were sorted into the poor prognosis group (PPG), and 140 (39.4%) were sorted into the severe prognosis group (SPG) by TSC analysis. For the TSC outcome, four variables with higher PI were identified, namely, Ca (PI = 1), albumin (PI = 0.62), WBC count (PI = 0.5) and NE% (PI = 0.45). Compared with the SPG, the BPG presented better outcomes after surgery events. The TSC outcome model was efficient in distinguishing the duration of bowel function recovery and hospital stay by Kaplan‒Meier curves. Via multivariate analysis, a RS consisting of four risk factors, namely, constipation duration (OR = 1.002), APTT (OR = 0.923), PT (OR = 1.449) and PCT (OR = 1.540), was identified. The AUC of the RS on the TSC outcome model was 0.719 (95% CI, 0.635-0.804).

CONCLUSION

A novel TSC outcome model and RS system was constructed to comprehensively reflect the tailored treatment, surgical events and posttreatment recovery for SBO patients.

Clinical characteristics and risk factors for secondary lymphoedema in hidradenitis suppurativa

Lymphoedema – a chronic inflammatory disorder associated with hidradenitis suppurativa (HS) – significantly impairs function and patients’ quality of life. Herein, we present a retrospective review of a multicentre cohort of patients with HS with secondary lymphoedema.

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.

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).

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: 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.

IRAK4 degrader in hidradenitis suppurativa and atopic dermatitis: a phase 1 trial

Toll-like receptor-driven and interleukin-1 (IL-1) receptor-driven inflammation mediated by IL-1 receptor-associated kinase 4 (IRAK4) is involved in the pathophysiology of hidradenitis suppurativa (HS) and atopic dermatitis (AD). KT-474 (SAR444656), an IRAK4 degrader, was studied in a randomized, double-blind, placebo-controlled phase 1 trial where the primary objective was safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics and clinical activity in patients with moderate to severe HS and in patients with moderate to severe AD. KT-474 was administered as a single dose and then daily for 14 d in 105 healthy volunteers (HVs), followed by dosing for 28 d in an open-label cohort of 21 patients. Degradation of IRAK4 was observed in HV blood, with mean reductions after a single dose of ≥93% at 600-1,600 mg and after 14 daily doses of ≥95% at 50-200 mg. In patients, similar IRAK4 degradation was achieved in blood, and IRAK4 was normalized in skin lesions where it was overexpressed relative to HVs. Reduction of disease-relevant inflammatory biomarkers was demonstrated in the blood and skin of patients with HS and patients with AD and was associated with improvement in skin lesions and symptoms. There were no drug-related infections. These results, from what, to our knowledge, is the first published clinical trial using a heterobifunctional degrader, provide initial proof of concept for KT-474 in HS and AD to be further confirmed in larger trials. ClinicalTrials.gov identifier: NCT04772885 .

Azathioprine in hidradenitis suppurativa with inflammatory phenotype: a case series of 11 patients

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that negatively impacts the quality of life of patients. It presents as deep-seated nodules, abscesses, fistulae, sinus tracts, and scars in the axilla, inguinal area, submammary folds, and perianal area. Recently, two phenotypes have been described: a follicular phenotype and an inflammatory phenotype. Numerous medical treatments are available for hidradenitis suppurativa, with particular importance of antitumor necrosis factor antibodies. Due to the association of HS with other conditions with a pro-inflammatory state, particularly Crohn's disease, it has been suggested that azathioprine may have a role in the treatment of HS.

OBJECTIVE

To assess the effectiveness of azathioprine monotherapy in patients with moderate-severe HS.

METHODS

We retrospectively studied patients with HS treated with azathioprine in monotherapy. We performed both clinical and ultrasound evaluation at baseline as well as in the follow-up visits. Their baseline score on the iHS4 and DLQI scales and 12-16 weeks after starting the treatment were compared. We also registered the number of patients who achieved HiSCR.

RESULTS

Six patients presented significant improvement, reducing their score in iHS4 and DLQI scales and achieving HiSCR. Another patient had clinical improvement, meaning reduction in iHS4 and DLQI, but without achieving HiSCR. Two patients stopped the treatment before week 12 because of adverse events. The remaining two patients presented no improvement. The median (Q3-Q1) baseline iHS4 score was 6 (12-6), and follow-up iHS4 score, 4 (6-2), being these differences statistically significant (P = 0.006). Median (Q3-Q1) baseline DLQI scores and 12-16 weeks after treatment were 17 (23-11) and 14 (18-9) although statistically nonsignificant (P = 0.099).

CONCLUSION

We present a case series of 11 patients treated with azathioprine with good clinical and ultrasonographic response. We suggest that azathioprine may benefit a certain patient profile with the inflammatory phenotype.

Pilonidal Sinus Disease is Associated with Severe Hidradenitis Suppurativa in a Spanish Cohort

Hidradenitis suppurativa is a chronic inflammatory disorder of the hair follicle with a high level of morbidity. Pilonidal sinus disease is a comorbid disorder and may be the reason for first contact with the healthcare system of patients with hidradenitis suppurativa. The aim of this study was to evaluate the frequency of association of pilonidal sinus disease and hidradenitis suppurativa and to explore whether pilonidal sinus disease defines a different clinical profile for patients with hidradenitis suppurativa. A cross-sectional study in which data regarding past history of pilonidal sinus disease, clinical and sociodemographic information were recorded during the first visit to the Hidradenitis Suppurativa Clinic of 2 tertiary hospitals. A total of 839 patients were included in the study. Of these, 51.7% (434/839) were male and mean age was 37.3 ± 13.6 years. Pilonidal sinus disease was present in 32.6% (269/839) of the patients and was associated with an early debut of hidradenitis suppurativa, a higher Hurley stage, inflammatory phenotype and a greater number of fistulas and perianal involvement. Elapsed time between pilonidal sinus disease and diagnosis of hidradenitis suppurativa was associated with higher disease severity. Pilonidal sinus disease is a frequent comorbidity and risk marker for hidradenitis suppurativa disease severity. Pilonidal sinus disease could be a sentinel event to identify patients who would benefit from close treatment and follow-up.

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.

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.

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.

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.

Hidradenitis suppurativa and psoriasis: the odd couple

Psoriasis and hidradenitis suppurativa are chronic inflammatory skin diseases that can develop together, negatively impacting on the patient's quality of life. We aimed to review the most up-to-date information regarding the epidemiology, pathogenesis, clinical presentation and possible therapeutical choices in patients with both psoriasis and hidradenitis suppurativa, thus linking these two autoimmune and autoinflammatory conditions. A narrative review of articles dating from 2017 to 2022 has been performed using the PubMed database. We analyzed the case reports and case series found in the literature regarding patients who suffered from both psoriasis and HS. Psoriasis arose before hidradenitis suppurativa in the majority of cases, while only a minority of them had hidradenitis suppurativa before psoriasis. Interestingly, some patients suffered from paradoxical hidradenitis suppurativa following biological therapy administered to treat the already present psoriasis. Lastly, new biological drugs have been marketed with great success for the outcome of psoriasis, but similar progress did not happen for hidradenitis. Novel therapeutic approaches and lines of research are needed for the treatment of these pathologies, even if concomitant, in order to improve patient's quality of life.

Interpreting the spectrum of gamma-secretase complex missense variation in the context of hidradenitis suppurativa—An in-silico study

Hidradenitis suppurativa (HS) is a disease of the pilosebaceous unit characterized by recurrent nodules, abscesses and draining tunnels with a predilection to intertriginous skin. The pathophysiology of HS is complex. However, it is known that inflammation and hyperkeratinization at the hair follicle play crucial roles in disease manifestation. Genetic and environmental factors are considered the main drivers of these two pathophysiological processes. Despite a considerable proportion of patients having a positive family history of disease, only a minority of patients suffering from HS have been found to harbor monogenic variants which segregate to affected kindreds. Most of these variants are in the ɣ secretase complex (GSC) protein-coding genes. In this manuscript, we set out to characterize the burden of missense pathogenic variants in healthy reference population using large scale genomic dataset thereby providing a standard for comparing genomic variation in GSC protein-coding genes in the HS patient cohort.

What's Race Got to Do With It? CRP Levels in Immune Mediated Skin Diseases: Considerations for Hidradenitis Suppurativa

Currently, there is a lack of racial/ethnic heterogeneity in research databases, exposing a systematic issue in studies exploring inflammation-mediated diseases, such as hidradenitis suppurativa (HS). HS is a chronic inflammatory skin condition that disrupts normal structure and functioning of terminal hair follicles, resulting in the formation of recurrent abscesses, nodules, and sinus tracts within intertriginous regions. Studies have described higher serum levels of inflammation-mediated C-reactive protein (CRP) in patients with HS, a disease that predominantly affects skin of color (SOC) populations. Herein, we explore the role of CRP levels in the context of HS disease presentation, management, and psychosocial implications in SOC patients to determine existing disparities in research studies.

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.

The Genomic Architecture of Hidradenitis Suppurativa-A Systematic Review

Hidradenitis suppurativa is a chronic, suppurative condition of the pilosebaceous unit manifesting as painful nodules, abscesses, and sinus tracts mostly in, but not limited to, intertriginous skin. Great strides have been made at elucidating the pathophysiology of hidradenitis suppurativa, which appears to be the product of hyperkeratinization and inflammation brought about by environmental factors and a genetic predisposition. The identification of familial hidradenitis suppurativa has sparked research aimed at identifying underlying pathogenic variants in patients who harbor them. The objective of this review is to provide a broad overview of the role of genetics in various aspects of hidradenitis suppurativa, specifically the pathophysiology, diagnosis, and clinical application.

New perspectives on the treatment of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by the presence of painful nodules, abscesses, chronically draining fistulas, and scarring in apocrine gland-bearing areas of the body. The exact pathogenesis of HS is not yet well understood, but there is a consensus in considering HS a multifactorial disease with a genetic predisposition, an inflammatory dysregulation, and an influence of environmental modifying factors. Therapeutic approach of HS is challenging due to the wide clinical manifestations of the disease and the complex pathogenesis. This review describes evidence for effectiveness of current and emerging HS therapies. Topical therapy, systemic treatments, biological agents, surgery, and light therapy have been used for HS with variable results. Adalimumab is the only US Food and Drug Administration (FDA) approved biologic agent for moderate-to-severe HS, but new therapeutic options are being studied, targeting different specific cytokines involved in HS pathogenesis. Comparing treatment outcomes between therapies is difficult due to the lack of randomized controlled trials. Treatment strategy should be selected in concordance to disease severity and requires combination of treatments in most cases.

Dapsone in hidradenitis suppurativa: A case series of 56 patients

Hidradenitis suppurativa (HS) is a chronic inflammatory disease with a challenging treatment. Current guidelines reserve dapsone as a third line agent for patients with mild to moderate HS. To our knowledge, only four small case series have been reported. The objective of this study was to assess the effectiveness and safety of dapsone in our clinical practice. A retrospective observational single-center study of 56 HS patients who underwent treatment with dapsone from May 1, 2015, to June 1, 2021, was performed. The Hidradenitis Suppurativa Clinical Response (HiSCR) scale was used to evaluate the response to treatment. Fifty-six patients were included, 66% of which were men, with a median age of 33 years. Most of them had mild or moderate disease and belonged to LC2 follicular phenotype. All patients had been refractory to first-line treatments. Dapsone was prescribed at doses of 50-150 mg/day. 62.5% of the patients achieved HiSCR after 12 weeks of treatment. No serious adverse reactions were detected. The median duration of treatment was 8 months. After multivariate analysis, an association was found between the presence of fistulous tracts and the risk of non-response to the drug. In four of the dapsone responders, oral retinoids were added to achieve a sustained response. Limitations include the retrospective and non-controlled nature of this study. In conclusion, dapsone is an effective and well-tolerated option for long-term HS treatment, and in this series, it was mainly chosen for patients with LC2 phenotype. It would be interesting to study combination with retinoids and other management options.

Metabolic syndrome and hidradenitis suppurativa: epidemiological, molecular, and therapeutic aspects

Hidradenitis suppurativa (HS) is a chronic, suppurative condition of the pilosebaceous unit. Patients suffering from HS demonstrate a molecular profile in keeping with a state of systemic inflammation and are often found to fit the criteria for a diagnosis of metabolic syndrome (MetS). In this paper, we review the literature with regards to established data on the prevalence of MetS in HS patients and revise the odds ratio of comorbid disease. Furthermore, we attempt to draw parallels between inflammatory pathways in HS and MetS and evaluate how convergences may explain the risk of comorbid disease, necessitating the need for multidisciplinary care.

Autoinflammatory keratinitzation diseases (AIKDs

Autoinflammatory keratinization disease (AiKD) is a novel clinical concept encompassing diseases with a genetic background and mixed pathogenic mechanisms of autoinflammation and autoimmunity, leading to an aberrant keratinization of the skin. Recent advances in medical genetics have revealed genetic causes and/or predisposing factors for a number of AiKD's, such as mutations in IL36RN related with pustular psoriasis, acrodermatitis continua and hidradenitis suppurativa, in CARD14 in pityriasis rubra pilaris type V and some forms of pustular psoriasis, and in NLRP1 related with familial keratosis lichenoides chronica (KLC). It is suspected that AiKD pathophysiology would also be involved in non-monogenic disorders. The bidirectional relationship between inflammation and keratinization should be understood in order to outline optimal management, and new drug development should take both targets into account. We assume that new inflammatory keratinization diseases may be recognized as AiKDs in the coming years.