Hidradenitis suppurativa: from pathogenesis to diagnosis and treatment

Mediterranean diet, lifestyle and quality of life in Sardinian patients affected with Hidradenitis suppurativa

Background: Hidradenitis Suppurativa is a chronic inflammatory skin disease with a strong negative impact on physical and psychological health. Obesity, especially visceral adiposity, but also smoking or unhealthy nutritional habits, have been reported to be significantly associated with hidradenitis suppurativa.

Design and methods: Case-control study in 35 patients of both sexes affected with hidradenitis suppurativa, and 35 healthy subjects matched for sex, age, and geographic origin (Sardinia, Italy).

Results: Several anthropometric measures (body mass index, waist circumference, body composition), lifestyle (Mediterranean diet adherence, and physical activity level), and the perceived physical and mental health status were evaluated in case and controls. Hidradenitis patients showed significantly higher values of body mass index, waist circumference, body composition, fat mass, and lower values of physical and mental health status compared to controls, while both groups showed a similar moderate physical activity level which can be assumed to counteract the negative effects of obesity or poor nutritional pattern in hidradenitis patients. However, none of the evaluated variables were correlated with the severity of the disease, assessed by means of the Hurley stage system or the Sartorius score. Instead, the Sartorius score showed a positive correlation with the duration of hidradenitis, mainly imputable to the diagnostic delay and the consequent long lasting inflammatory status.

Conclusions: Although nutritional factors and lifestyle can be important and modifiable factors in the hidradenitis suppurativa course, the detrimental effect of chronic inflammation and delayed management are clearly prevalent and heavily influence the disease burden.

Are dissecting cellulitis and hidradenitis suppurativa different diseases?

Although dissecting cellulitis (DC) and hidradenitis suppurativa (HS) are classified separately, they share many clinical, dermatoscopic, pathogenetic, and histologic aspects, as well as therapeutic options. The association between DC, HS, and acne conglobata represents the follicular occlusion triad or follicular occlusion tetrad, which may include a pilonidal sinus. DC, also known as "folliculitis et perifolliculitis capitis abscendes et suffoidens," is classified as a secondary cicatricial and neutrophilic alopecia. It occurs with perifolliculitis of the scalp, dermal abscesses, sinus tract development, and secondary scarring alopecia. HS, sometimes known as acne inversa, is a chronic relapsing inflammatory disease afflicting apocrine gland-rich areas of the body with painful nodules and abscesses, sinus tracts, and scarring. Given the overlap between the clinical features and the pathogenesis of DC and HS, it would be more appropriate to consider these conditions as two different localizations of the same disease rather than two different pathologies, being a follicular occlusion disease occurring on the scalp and on the apocrine gland-rich areas of the body.

Development of In-Situ Spray for Local Delivery of Antibacterial Drug for Hidradenitis Suppurativa: Investigation of Alternative Formulation

Hidradenitis suppurativa (HS) has been considered an orphan disease with limited treatments available. The available topical treatment for this condition is clindamycin lotion; however, short retention and frequent application are the main setbacks. Thus, the present study aimed to attain an optimized antibacterial in situ spray formulation for the hidradenitis suppurativa skin condition, which gels once in contact with the skin surface at around 37 °C and possesses bioadhesion as well as sustained-release properties of the incorporated drug. Different concentrations of thermo-reversible gelling polymer, Pluronic F-127, were investigated along with the selected bioadhesive polymers, HPMC and SA. The optimized formulation F3 consisting of 18% Pluronic F-127 with 0.2% HPMC and 0.2% SA was characterized based on various physicochemical properties. The gelation temperature of F3 was found to be 29.0 ± 0.50 °C with a gelation time of 1.35 ± 0.40 min and a pH of 5.8. F3 had the viscosity of 178.50 ± 5.50 cP at 25 °C and 7800 ± 200 cP at 37 °C as the gel set. The optimized formulation was found to be bioadhesive and cytocompatible. Cumulative drug release was 65.05% within the time-frame of 8 h; the release pattern of the drug followed zero-order kinetics with the Higuchi release mechanism. The average zone of inhibition was found to be 43.44 ± 1.34 mm. The properties of F3 formulation reflect to improve residence time at the site of application and can enhance sustained drug release. Therefore, it could be concluded that optimized formulation has better retention and enhanced antimicrobial activity for superior efficacy against HS.

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.

Sexual Dysfunction in Patients with Hidradenitis Suppurativa: A Systematic Review and Meta-Analysis

BACKGROUND

Hidradenitis suppurativa (HS) can be a severe condition that impacts patients' health and quality of life. One aspect that can be impaired is sexual health, with many patients suffering from sexual dysfunction (SD). There are numerous articles describing this association.

OBJECTIVE

We sought to synthesize and analyze the recent available evidence on HS and SD.

METHODS

A systematic review was conducted. Three medical databases were used: Medline, Embase, and Cochrane. All types of epidemiological articles were included, while reviews, guidelines, protocols, conference abstracts, and case report articles were excluded. This review covers the past eight years.

RESULTS

Twelve studies were included for review, with the most common study design being cross-sectional. Most studies involved surveys and questionnaires, with some using control groups to compare results. SD affected roughly half of patients with HS, and was found more frequently in women. Comorbidities included psychological conditions, such as depression and low self-esteem, as well as metabolic and cardiovascular diseases.

CONCLUSION

HS is significantly associated with sexual health issues, including SD in women and erectile dysfunction in men.

The Role of Oral Contraceptive Pills in Hidradenitis Suppurativa: A Cohort Study

There is a need to establish the role of antiandrogens as an alternative or concomitant therapy for hidradenitis suppurativa (HS). Thus, the objectives of this study are (1) to assess the effectiveness of oral contraceptive pills (OCPs) at week 12 in HS women, and (2) to describe the clinical profile of patients receiving oral contraceptive pills (OCPs). A prospective observational study was designed. This study included 100 participants, 50 women with HS who started OCPs for the first time at our HS Clinic and 50 participants without OCP treatment. The main outcome of interest was the percentage of reduction in total abscess and inflammatory nodule (AN) count at week 12. Thirty-three women received combined OCPs and 17 non-combined OCP. HS patients with OCPs treatment were younger (31.7 vs. 40.9 years, p < 0.001), thinner (28.62 vs. 33.35 kg/m²), and have a higher number of areas affected (2.32 vs. 1.38, p = 0.02) than those without OCPs. After 12-weeks of treatment, it was observed that the percentage of AN reduction was higher in HS women receiving OCP than in patients without OCP (53.9% vs. 38.42%, p = 0.049). It was observed that OCP prescription (β = 3.79, p = 0.034) and concomitant therapy (β = 3.91, p = 0.037) were independently associated with a higher % AN when controlling for disease duration, concomitant therapy, and treatment with/without OCP (R² = 0.67). The factors potentially associated with the percentage AN reduction at week 12 in HS women treated with OCPs were disease duration (β = -1.327, p = 0.052), concomitant therapy (β = 11.04, p = 0.079), and HS worsening with the menstrual cycle (β = 10.55, p = 0.087). In conclusion, OCPs might be effective for improving AN count in women with HS. Women whose HS worsens in relation to the menstrual cycle and have a shorter disease may benefit more from the therapeutic effect of OCPs.

Association of Trimethylamine N-Oxide (TMAO) with the Clinical Severity of Hidradenitis Suppurativa (Acne Inversa)

In this case-control, cross-sectional, observational study, we evaluated circulating trimethylamine n-oxide (TMAO) levels, a gut-derived metabolite associated with inflammation and cardiometabolic risk, in patients with hidradenitis suppurativa (HS), a highly disabling inflammatory skin disease associated with an elevated prevalence of comorbidities, especially cardiovascular and metabolic diseases. In this study, we enrolled 35 naive-treatment patients with HS and 35 controls, matched for sex, age, and body mass index (BMI). HS Sartorius score was 49.0 (33.0–75.0), while according to the Harley system 12 and 23 patients presented grade 1 and grade 2 severity, respectively. HS patients had a lower adherence to the Mediterranean diet (MD) (p = 0.002), lower phase angle (PhA) (p < 0.001), and higher circulating TMAO levels (p < 0.001) than the control group. HS patients with grade 2 rather than grade 1 of Harley grade severity showed a higher BMI (p = 0.007), waist circumference (p = 0.016), total energy intake (p = 0.005), and lower PhA (p < 0.001) and adherence to the MD (p = 0.003). Of interest, patients with Hurley grade 2 of severity exhibited higher circulating TMAO levels (p < 0.001) compared to grade 1. Circulating TMAO levels showed a positive correlation with HS Sartorius score even after adjustment for confounding covariates, including BMI, waist circumference, adherence to the MD, total energy intake, and PhA (r = 0.570, p = 0.001). Using a linear regression model, circulating TMAO levels and PhA were the main predictors of the clinical severity of HS.

Adalimumab Induces a Wound Healing Profile in Patients with Hidradenitis Suppurativa by Regulating Macrophage Differentiation and Matrix Metalloproteinase Expression

Adalimumab (ADA) is the only Food and Drug Administration‒approved treatment for moderate-to-severe hidradenitis suppurativa, whereas etanercept and certolizumab-pegol have been shown to be ineffective, suggesting that the mechanism of action of ADA is distinct in hidradenitis suppurativa and may contribute to improved wound healing. Given that macrophages (Mϕs) play pivotal roles throughout the wound healing process, an in vitro Mϕ differentiation assay was carried out to assess the impact of TNF‒anti-TNF complexes on these cells. TNF‒ADA complexes exhibited stronger inhibitory effects on inflammatory Mϕ differentiation. Moreover, RNA sequencing revealed several unique wound healing profiles for TNF‒ADA‒treated inflammatory Mϕs, which were not observed for those treated with either TNF‒etanercept or TNF‒certolizumab-pegol complexes, including the inhibition of the matrix metalloproteinase (MMP) pathway. In addition, ADA administration was found to significantly reduce the levels of inflammatory MMP-1 and MMP-9 while promoting wound-healing MMP-13 and tissue inhibitor of metalloproteinases 2 levels in the circulation of the patients with hidradenitis suppurativa who responded to treatment. Our in vitro findings show that TNF‒ADA‒treated inflammatory Mϕs exhibit a distinct profile resembling wound healing. Moreover, ADA not only differentially regulates MMP expression in patients with hidradenitis suppurativa responding to the therapy but also potentially induces a transition to a profile suggestive of wound healing.

Mapping risk factors for cumulative life course impairment in patients with chronic skin diseases - a systematic review

Patients with chronic skin diseases suffer from physical and psychosocial impairments which can lead to a cumulative life-long burden. Therefore, the concept of cumulative life course impairment (CLCI) was introduced, referring to the non-reversible damage due to the persistent life-long burden. This systematic review (PROSPERO registry number: CRD42020179141) aimed at mapping the risk factors and the associated burden over time in patients with psoriasis, atopic dermatitis (AD) and hidradenitis suppurativa (HS). Three electronic databases were searched (date of the last search: December 2019). Studies with a longitudinal study design that assessed the association between a risk factor and the associated burden over time in patients with psoriasis, AD and HS were included. Quality assessment of the included studies was done using Critical Appraisal Skills Programme (CASP) checklists. In total, 40 publications reflecting 25 different studies were included: nine studies addressed patients with psoriasis, 13 patients with AD, two studies included patients with HS and one study enrolled patients with psoriasis and AD, respectively. Twenty-two potential risk factors with underlying evidence were found in this review. These risk factors include mainly sociodemographic (such as age or gender) and clinical (such as disease severity or comorbidities) variables. Disease severity and comorbidities were the most often studied risk factors, while only a few studies evaluated psychosocial risk factors over time. Patients with chronic skin diseases are at high risk to develop a life-long negative impact from the disease. However, there is a lack of data that evaluates the psychosocial burden and its influence on the patients' life course over time. The risk factors found in this review help to identify patients at risk, to treat them adequately and, ultimately, to prevent CLCI. These results can be the basis to develop a highly needed tool to assess the risk for CLCI in the future.

A safety review of biologic therapies for the management of hidradenitis suppurativa and unmet needs

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin disorder characterized by nodules, abscesses, fistulae, and significant scarring in intertriginous areas rich in apocrine glands. Immunomodulator drugs, including biologics, are a mainstay of treatment for this disease.

AREAS COVERED

This review details the safety profiles of various biologic therapies currently available commercially that have been tried for HS as assessed in clinical trials and observational studies. As the only Food and Drug Administration (FDA)-approved medication for the treatment of moderate-to-severe HS, adalimumab is discussed in the most detail. Additional biologic medications, including tumor necrosis factor α (TNFα) inhibitors, interleukin 1 (IL-1) inhibitors, IL-12 and IL-23 inhibitors, IL-17 inhibitors, and IL-23 inhibitors, are discussed as well. Safety concerns in special populations, including pregnant women and children, are outlined.

EXPERT OPINION

Existing data support excellent short-term and long-term safety profiles for adalimumab, although caution must be taken with use in high-risk patient populations, including those with chronic infections or increased risk of malignancy. Based on their safety data for other indications, additional biologic agents appear safe in HS as well. However, further research is needed to fully understand the safety profiles of these medications in the HS population.

Potential predictive biomarkers of adalimumab response in patients with hidradenitis suppurativa

BACKGROUND

Adalimumab provides significant efficacy for patients with hidradenitis suppurativa (HS), which was demonstrated by at least 50% of patients achieving a clinical response by week 12 that was maintained through to week 168 in the PIONEER trials.

OBJECTIVES

To identify whether there are biomarkers that could predict adalimumab response, as well as markers that differentially respond to adalimumab in patients with HS.

METHODS

Baseline and week-12 plasma samples from the PIONEER studies were used to assess the levels of circulating proteins by multiplex and enzyme-linked immunosorbent assays.

RESULTS

Analyses revealed significantly higher high-sensitivity C-reactive protein (hs-CRP) and chemokine (C-C motif) ligand (CCL) 16 (HCC-4) levels in nonresponders at baseline and identified a multivariate response signature of calprotectin, fractalkine and HCC-4, reaching an 86% predictive accuracy rate for adalimumab response. Additionally, post-treatment reduction of plasma C-X-C motif chemokine ligand (CXCL)9, CXCL8 (interleukin-8) and CCL19 (macrophage inflammatory protein 3β) were greater in adalimumab super-responders than in nonresponders (P = 0·026, P = 0·044 and P = 0·026, respectively). These cytokines are involved in the recruitment of innate and adaptive inflammatory cells, and/or stimulation of certain inflammatory responses, suggesting that these pathways could be disease drivers in adalimumab nonresponders.

CONCLUSIONS

These initial results suggest HCC-4, calprotectin and fractalkine could be potential predictive biomarkers of adalimumab response in HS and identified possible tumour necrosis factor-independent disease pathways.

Epidemiology of hidradenitis suppurativa in Taiwan: A 14-year nationwide population-based study

Hidradenitis suppurativa (HS), also called acne inversa, is an inflammatory skin disease, which causes HS patients to suffer from recurrent symptoms and severe comorbidities. The aim of this article was to provide evidence on the epidemiology of HS in Taiwan through a retrospective population-based cohort study. The patients with International Classification of Diseases, Ninth Revision, Clinical Modification code 705.83 and Anatomical Therapeutic Chemical codes for HS treatments from 2000 to 2013 in the National Health Insurance Research Database, which covers 99.9% Taiwanese residents, were enrolled in this 14-year nationwide population-based cohort study. The age- and sex-standardized prevalence, incidence, and the prescription pattern for HS were analyzed. The annual percent change (APC) was used to estimate the trend of prevalence and incidence of HS from 2000 to 2013. During 2000-2013 in Taiwan, the 14-year period prevalence rate was 185.6/100 000 (95% confidence interval [CI], 177.3-194.3) with an APC of -2.96% (95% CI, -1.73 to -4.17) and the mean annual adjusted incidence rate from 2001 to 2013 was 11.8/100 000 (95% CI, 11.2-12.5) with an APC of -4.65% (95% CI, -3.32 to -5.95). Female : male ratio was 0.92 and the most common onset age was 15-24 years. Major treatments were systemic corticosteroids, systemic antihistamines, systemic antibiotics, and topical antibiotics. An increasing tendency of using systemic antibiotics was noted. In Taiwan, decreasing incidence and prevalence of HS was shown during 2000-2013. Relatively lower incidence and prevalence were noted compared to Western countries. Male predominance was revealed, and the use of systemic antibiotics became the mainstream in treatment for HS.

Management of Severe Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a devastating and disfiguring disease of the skin involving the terminal follicular epithelium within the apocrine-gland-bearing skin. We present an interesting case of a 58-year-old female who presented with a 10-year history of refractory HS of the gluteal, perineal, perianal, and groin region. She had been chronically treated with multiple antibiotics in the past with no improvement. The patient subsequently underwent surgical local excision with complex closure. Medical management alone may not be optimal, especially in refractory disease. Early and aggressive surgical intervention and interdisciplinary approach are needed for patients with chronic and advanced stage of HS.

Postoperative Quality of Life in Patients with Hidradenitis Suppurativa Utilizing the Hidradenitis Suppurativa Burden of Disease Tool

Background

Hidradenitis suppurativa (HS) severely impacts patients’ quality of life (QoL). Surgery has shown potential in improving a patient's QoL in severe disease. Previous studies have evaluated QoL after surgery, but lack a disease-specific questionnaire to better evaluate the unique burden of disease that patients with HS experience.

Objective

To measure postoperative QoL in patients with HS using a modified version of the disease-specific questionnaire, the Hidradenitis Suppurativa Burden of Disease (HSBOD) Tool.

Methods

A retrospective study was conducted using 19 patients who underwent surgery for HS. A demographic form and a 19-item disease-specific questionnaire were emailed to patients who consented to complete the survey. Patient-reported outcomes were recorded on a 0-100 scale (100 representing the highest burden of disease).

Results

Of the 24 patients that received the survey, 19 completed it in its entirety. The mean±SD Burden of Disease (BoD) score for each of the five domains assessed by the survey were: symptoms and feelings (62±27), daily activities (65±30), leisure (57±31), work and school (48±32), and personal relationships (56±27). Pearson’s correlation between the number of surgeries each patient underwent and their reported BoD scores were not significant. BoD scores were significantly higher in the symptoms and feelings domain for complex closure compared to both secondary intention and split-thickness skin grafting (STSG).

Conclusion

Despite having surgery, patients with hidradenitis still report impaired QoL. Further study is ongoing to determine how these measures compare to baseline preoperative values. This instrument provides a valuable tool to determine QoL in patients with hidradenitis.

The Microbiome in Hidradenitis Suppurativa: A Review

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic autoinflammatory skin disease. It is characterised by the development of abscesses and nodules in intertriginous anatomical sites. Whilst it is now recognised as an autoinflammatory condition rather than an infective disease, bacteria are implicated in disease pathogenesis.

METHODS

We performed a search of the literature from inception to 12 August 2020 using the search terms "hidradenitis suppurativa", "Verneuil's disease", "acne inversa", "microbiome", "bacteriology" and "microbiology". Studies were included if they assessed the cutaneous, gut or oral bacteria, bacteriology or microbiome in hidradenitis suppurativa.

RESULTS

Twenty-one studies examining the cutaneous microbiome and two studies examining the gastrointestinal microbiome in HS were identified. No studies examining the oral microbiome in HS were identified. A total of 972 patients and 46 healthy controls were included across studies examining the cutaneous microbiome. A total of 100 patients and 36 controls were included across both gut microbiome studies. Coagulase-negative Staphylococcus, anaerobes such as Porphyromonas and Prevotella, and Staphylococcus aureus species were commonly encountered organisms across the included cutaneous microbiome studies. The studies examining the gut microbiome were limited, with one small study demonstrating an alteration in the gut microbiome composition compared to controls. The other study found no alteration to the gut microbiome in patients with HS compared to those with inflammatory bowel disease (IBD) and HS, and IBD and/or psoriasis.

CONCLUSION

Research should be undertaken into the oral microbiome in HS. Further research should be undertaken examining the cutaneous and gut microbiome in HS, and its relationship with documented co-morbidities. Additionally, metagenomics-focused studies may help identify the relationship between microorganisms and host, and this may shed light on new pathways of disease pathogenesis. This may help identify potential future therapeutic targets.

Diagnosis and management of hidradenitis suppurativa in women

Hidradenitis suppurativa is a chronic inflammatory disease that disproportionately affects women of childbearing age. Hidradenitis suppurativa is characterized by painful nodules, abscesses, draining dermal tunnels, and scarring with a predilection for intertriginous sites, such as the axilla, groin, and breast regions. Delay in diagnosis and treatment of hidradenitis suppurativa often results in long-term sequelae leading to significant morbidity, and rarely mortality, in these patients. This clinical opinion suggests that obstetrician-gynecologists are uniquely poised to recognize early signs of hidradenitis suppurativa during routine well-woman examinations and initiate treatment or referral to dermatology. Herein, we provide clinical pearls for obstetrician-gynecologists caring for female patients with hidradenitis suppurativa, including strategies for comprehensive management and recommendations to improve the comfort of patients with hidradenitis suppurativa during examinations.

Surgical management of hidradenitis suppurativa with keystone perforator island flap

INTRODUCTION

Hidradenitis suppurativa is a chronic, relapsing disease of the skin, characterized by apocrine gland and pilosebaceous complex infections, causing recurrent superficial nodules and abscesses, fistula formation, scarring and fibrosis. It is accepted that wide local excision and local coverage is the crucial treatment to prevent recurrence of the disease.

MATERIALS AND METHODS

All patients presenting for surgical treatment of hidradenitis suppurativa between 2014 and 2019 were identified from the hospital database. Only patients with hidradenitis suppurativa confined to the axillary, inguinal or sacrococcygeal regions in Hurley grade II and III were included. A total of 21 patients (11 male, 10 female) aged between 21 and 76 years were evaluated retrospectively. All of the 22 defects were reconstructed with keystone perforator island flap following wide local excision. We performed descriptive analysis of demographic data, comorbidities, topographic distribution of lesions, Hurley scoring, size of defect, specific type of reconstruction, complications, follow-up period, recurrences.

RESULTS

21 patients with localized axillary, inguinal or sacrococcygeal hidradenitis suppurativa were identified, and 22 keystone perforator island flaps were performed. All keystone perforator island flaps survived giving a durable cover to the affected regions. There were no complications. Functional and aesthetic results were satisfactory and there were no recurrences.

CONCLUSION

These findings confirm that the keystone perforator island flap procedure can be effective for immediate defect reconstruction after wide local excision of advanced hidradenitis suppurativa of the axillary, inguinal and sacrococcygeal regions and provides excellent aesthetic results.

Race-Specific Prevalence of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic, inflammatory disease affecting approximately 1% of the global population. While age- and sex-specific prevalence of HS is well documented in literature, few studies have explored trends in racial predilections for HS. The objective of this study is to investigate the race-specific prevalence of HS. MEDLINE and EMBASE searches were conducted in the OVID database. Keywords included variations of “race,” “ethnicity,” “country,” “prevalence,” and “Hidradenitis suppurativa.” Studies were included if they were written in English or French, conducted on human participants, and had data on HS and race-specific prevalence. Meta-analyses, systematic and literature reviews, and irrelevant articles were excluded. Thirty-nine out of 184 articles met the inclusion criteria after abstract and full-text screening. Population distribution was scaled according to country-specific demographics reports. These demographic reports were extracted from each country’s national statistics report. The average HS prevalence rates were highest in African American populations (1.3%), lowest in Hispanics/Latinos (0.07%), and intermediate amongst Caucasian populations (0.75%). Total prevalence in all other ethnic groups (0.17%) was minor in comparison to African American and Caucasian populations. Since the highest rates of HS were found among African American population, literature has highlighted the possibility of a genetic etiology in HS development. However, further literature examining race-specific prevalence of HS internationally is required to accurately assess the frequency and underlying etiology of HS among varying racial populations.

Hidradenitis Suppurativa in a Patient Affected by Mayer-Rokitansky-Küster-Hauser Syndrome: Insight into the Role of Hormones in HS

Introduction

Hidradenitis suppurativa (HS) is an inflammatory skin disease, which usually occurs after puberty. Even if the pathogenesis of HS is still unproven, numerous studies hypothesized that the disease is triggered by genetic and environmental factors, with hormones playing a central role. Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital malformation in which a failure of Müllerian duct development results in absent uterus and fallopian tubes and malformations of the vagina.

Case Presentation

A 38-year-old Caucasian female referred at our outpatient clinic affected by HS. Before the appearance of HS manifestations, the patient referred to a gynecologist due to difficulties in getting pregnant. The sonographic findings were consistent with MRKH syndrome. An ovarian stimulation for in vitro fertilization was started. However, after 3 months the patient showed the first HS onset. After the hormonal treatment ended, a combined treatment with rifampicin and clindamycin was started, showing a great clinical improvement at week 10.

Discussion/Conclusion

HS usually appears after puberty, exhibits premenstrual flare, improves in pregnancy, and worsens postpartum, which indicates a role of hormones and particularly of androgens in its pathophysiology. Contrasting data are reported in the literature. Our case wants to strengthen the idea that hormones could play an important role, probably with other endogenous or exogenous factors. Multidisciplinary investigations will clarify which part is played by each factor in the pathogenesis of HS.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Hidradenitis Suppurativa and 1-Carbon Metabolism: Role of Gut Microbiome, Matrix Metalloproteinases, and Hyperhomocysteinemia

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin condition characterized by painful nodules which suppurate and later develop into scar tissues followed by the development of hypodermal tracts. Although the mechanisms behind HS are not fully understood, it is known that dietary factors play important roles in flare frequency and severity. We hypothesize that the high fat diet (HFD) causes dysbiosis, systemic inflammation, and hyperhomocysteinemia (HHcy) in susceptible individuals, which subsequently elevate inflammatory cytokines such as IL-1β, IL-6, IL-17, and tumor necrosis factor alpha (TNF-α). This increase in dysbiosis-led inflammation coupled with a dysregulation of the 1-carbon metabolism results in an increase in matrix metalloproteinases MMP-2, MMP-8, and MMP-9 along with tissue matrix remodeling in the development and maintenance of the lesions and tracts. This manuscript weaves together the potential roles played by the gut microbiome, HHcy, MMPs, and the 1-carbon metabolism toward HS disease causation in susceptible individuals.

Risk of connective tissue disease, morphoea and systemic vasculitis in patients with hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) has been associated with auto-inflammatory conditions, yet the risk of developing connective tissue disease (CTD), morphoea and systemic vasculitis has not been well-characterized.

OBJECTIVES

We sought to evaluate the risk of developing CTD, morphoea and systemic vasculitis in patients with HS.

METHODS

Using claims data, we identified patients with HS and used 2 : 1 risk-set sampling to identify patients without HS. Patients with existing CTD were excluded. Patient follow-up lasted until first occurrence of the following events: the occurrence of outcome (i.e. systemic lupus erythematosus, morphoea, systemic sclerosis, Sjogren's Syndrome and systemic vasculitis), death, disenrolment or end of data stream. Hazard ratios (HR) of developing CTD, morphoea and systemic vasculitis were computed after 1 : 1 propensity score (PS) matching.

RESULTS

After 2 : 1 risk-set sampling, we identified 78 122 HS patients and 156 247 non-HS comparators. The mean follow-up was 540 days. After PS matching, HS patients had an increased risk of systemic lupus erythematosus HR = 1.63 (1.31-2.03) and morphoea HR = 2.02 (1.32-3.11), compared to non-HS patients. We did not observe an increased risk for systemic sclerosis HR = 0.90 (0.59-1.44), Sjogren's Syndrome HR = 0.91 (0.73-1.14) or systemic vasculitis HR = 0.87 (0.64-1.20).

CONCLUSION

In this population-based study, we observed an increased risk of developing systemic lupus erythematous and morphoea subsequent to a first-recorded diagnosis of hidradenitis suppurativa.

Hidradenitis Suppurativa and Concurrent Psoriasis: Comparison of Epidemiology, Comorbidity Profiles, and Risk Factors

Introduction

Hidradenitis suppurativa (HS) is a chronic, debilitating, and inflammatory skin disease. The epidemiology of HS varies greatly, with an estimated prevalence ranging from 0.03% to 4% worldwide. Similar to psoriasis (PsO), HS also exhibits a systemic inflammatory nature with a spectrum of systemic comorbidities. A large health insurance claims (HICs) database is analyzed to determine the demography and epidemiology of HS, PsO, and HS with concurrent PsO (HS-PsO) patients. Furthermore, the comorbidity profiles, including the comorbidity risk of these patient populations, are analyzed.

Methods

This is a noninterventional retrospective analysis of anonymized HICs data using a subset of the Institute of Applied Health Research Berlin (InGef) database. The primary outcome is the prevalence and incidence of HS, PsO, and HS-PsO. Secondary outcomes include comorbidity profiles and a comorbidity risk analysis.

Results

The prevalence and incidence of HS were 0.0681% and 0.0101%, respectively. The prevalence of HS-PsO was 0.004% (6% of the total HS population). HS patients frequently suffered from arterial hypertension (45%), nicotine dependence (46%), obesity (41%), and depression (36%), which were more common in HS-PsO patients compared with HS alone. HS patients had an increased prevalence of metabolic, psychiatric, immune-mediated, and cardiovascular diseases, e.g., overweight/obesity [odds ratio (OR): 2.65, 95% confidence interval (CI) 2.37–2.96], depression (OR: 1.55, 95% CI 1.42–1.76), or seronegative rheumatoid arthritis (OR: 2.82, 95% CI 1.61–4.94) compared with the overall population. The increased risk of myocardial infarction in HS patients (OR: 4.1, 95% CI 3.5–4.8, adjusting for age/sex) was largely attributed to patient’s current smoking status (OR: 1.1, 95% CI 0.8–1.5, adjusting for smoking/age/sex).

Conclusions

HS patients show a broad spectrum of inflammatory and metabolic syndrome-related comorbidities, with an increased risk by concurrent PsO. Important for clinical practice, the elevated cardiovascular risk of HS patients can be largely attributed to smoking.

Electronic supplementary material

The online version of this article (10.1007/s13555-020-00401-y) contains supplementary material, which is available to authorized users.

Characterization and Management of Inflammatory Eye Disease in Patients with Hidradenitis Suppurativa

Purpose: To assess the spectrum and treatment outcomes of inflammatory eye disease (IED) in subjects with hidradenitis suppurativa (HS).Methods: We conducted a single center retrospective chart review of 236 patients with HS seen for ophthalmic examination between 2013 and 2018.Results: Of 236 subjects with HS, 22 subjects (9.3%) were found to have IED. Seven of 22 subjects had more than one IED diagnosis. Anterior uveitis was the most common type of IED (40.9% of subjects with IED). Episcleritis, optic neuritis, keratitis, scleritis, intermediate and posterior uveitis, trochleitis, and dacryoadenitis were also observed. Of subjects with HS and IED, 59.1% did not have any other inflammatory or autoimmune disease that could explain the etiology of their IED. Eleven patients with IED were treated with systemic immunosuppression, with IED as the principal factor directing treatment in three patients.Conclusions: IED may be independently associated with HS and may benefit from systemic immunosuppression.

Knowledge about and determinants for diagnosing hidradenitis suppurativa by ministry of health primary healthcare physicians in Jeddah city 2019: An analytical cross-sectional study

Context:

Hidradenitis suppurativa is a noncontagious, inflammatory, chronic and recurrent disease. The prevalence of HS is estimated to be between less than 1 and 4%. It is more common in females than males at a 2:1 ratio. Many cases of HS are either misdiagnosed or remain undiagnosed.

Aims:

To assess knowledge of diagnosing hidradenitis suppurativa by Ministry of Health primary health care physicians in Jeddah city, 2019 and to identify the determinants and knowledge of diagnosing hidradenitis suppurativa.

Settings and Design:

An analytical cross-sectional study conducted in Jeddah city, 2019, among primary health care physicians of the MOH.

Methods and Material:

Estimated sample size was 114. The required primary health care centers were 38 centers. The centers were chosen by a simple random sampling technique. A reliable self-administered questionnaire was used. Ethical approval was obtained.

Statistical Analysis Used:

Descriptive statistics consisted of means, standard deviations, frequency tables, cross tabulation and charts). Categorical variables were compared using the chi–square test to determine significant relationships between variables.

Results:

65.4% (68) diagnosed the disease correctly. Most of their knowledge came from clinical practice (39.4%). There was a significant relationship with current job title and medical degree (P-value < 0.0005).

Conclusion:

The present study showed good knowledge about and ability to diagnose HS. A more advanced medical degree and more years of clinical experience was positively associated with the ability to diagnose HS.

Paradoxical Hidradenitis Suppurativa in Patients Receiving TNF-α Inhibitors: Case Series, Systematic Review, and Case Meta-Analysis

BACKGROUND/AIMS

TNF-α inhibitors represent the most advanced approved therapeutic option for moderate and severe forms of hidradenitis suppurativa (HS). However, in recent years, cases of paradoxical HS secondary to the use of these biological drugs have been described, with very few cases reported in the literature. The aims of this study are (1) to present 2 new cases of paradoxical HS and (2) to perform a systematic review of scientific evidence regarding paradoxical HS with TNF-α inhibitors.

MATERIAL AND METHODS

This is a retrospective study in which we searched all the cases of paradoxical HS secondary to the use of TNF-α inhibitors published in the literature and included two additional cases observed in our clinical practice.

RESULTS

A total of 34 patients under TNF-α inhibitor treatment were included (adalimumab = 21; infliximab = 9; etanercept = 4). The median delay from exposure to TNF-α inhibitor and the development of paradoxical HS was 12 months (range 1-72). The majority of patients were Hurley stage II (58.8%). Clinical improvement and complete remission were more frequent when the TNF-α inhibitor was stopped or switched to another biological agent with a different therapeutic target rather than maintenance or change to another TNF-α inhibitor.

CONCLUSIONS

Paradoxical HS is an unusual adverse effect of TNF-α inhibitors. When this adverse effect appears, interruption or substitution of treatment is associated with a better clinical outcome.

Biologic therapies for the treatment of hidradenitis suppurativa

Introduction: Hidradenitis suppurativa (HS) is a chronic skin disorder characterized by inflammatory nodules, abscesses, and fistulae. Patients tend to present in young adulthood and are predominantly female. The pathogenesis of HS involves apopilosebaceous gland follicle occlusion and affected areas often occur where this type of gland predominates. Treatment selection depends on HS severity, which is included in different scoring systems. In recent years, biological therapies have been evaluated and used with increasing frequency in moderate-to-severe HS disease.Areas covered: This review focuses on biological therapies for HS as assessed in case reports, case series, and clinical trials. The efficacy, hidradenitis suppurativa scoring systems, and long-term results of these therapies are discussed depending on the studies' endpoints.Expert opinion: Adalimumab is currently the only FDA-approved HS biological therapy. Some patients do not experience treatment efficacy with adalimumab at 40 mg/week, which may result in increasing the dose or seeking other treatments. Infliximab is the next line of HS treatment with demonstrated efficacy. Other biological therapies being studied have demonstrated efficacy in small patient groups, but lack study power. Further studies may provide answers to seeking treatment options for patients who fail to improve on current standard HS treatment.

Hidradenitis Suppurativa: Current Understanding of Pathogenic Mechanisms and Suggestion for Treatment Algorithm

Hidradenitis suppurativa is one of the most distressing dermatological conditions and has a significant negative impact on patients' quality of life. However, the exact pathogenic mechanisms remain incompletely understood and-therefore-efficient therapies are still lacking. The current manuscript focuses on new findings on its pathogenic mechanisms and aims to provide practical therapy recommendations.

Pediatric Endoscopic Hidradenitis Treatment: A New Minimally Invasive Treatment for Pediatric Patients with Hidradenitis Suppurativa

Background: Hidradenitis suppurativa (HS) is infrequent in the pediatric population. When indicated, surgery is often invasive, painful, and with significant recurrence rate. We aimed to report our preliminary experience using a new endoscopic technique to treat this pathology. Materials and Methods: We reported the data of 11 patients (9 girls and 2 boys) with average age of 15.7 years (range 14-17) with HS, who were operated using endoscopic procedure for a 15-month period. Six patients presented axillary, inguinal, and inframammary localizations, 3 patients presented axillary and inguinal localizations, and 2 patients presented only inguinal localization. Pediatric endoscopic hidradenitis treatment (PEHT) followed the same principles of pediatric endoscopic pilonidal sinus treatment (PEPSiT). The fistuloscope was introduced into the different holes, and after using an endobrush, all tracts were cauterized using monopolar electrode or laser energy, and finally the granulation tissues were removed using graspers. At the end of the procedure, all the holes were filled with oxygen-enriched oil-based gel and covered with fat gauze. Results: The average operative time was 47 minutes (range 30-80). All procedures were performed in a day surgery setting or with an overnight hospitalization. All patients reported no pain postoperatively and performed a local dressing with silver sulfadiazine spray and oxygen-enriched oil-based gel two times per day for 1 month postoperatively. At the longest follow-up of 1 year, the lesions were completely healed in all cases. Two patients (18%) developed further lesions in different untreated localizations that were successfully treated using PEHT. Conclusions: PEHT is a minimally invasive, effective, and safe treatment option for pediatric patients with HS. All patients reported a painless postoperative period and excellent results. Postoperative local dressings using oxygen-enriched oil-based gel and silver sulfadiazine spray are fundamental to achieve the complete healing. However, a further evidence with larger series and longer follow-up is required to confirm these preliminary results.

Extensive hidradenitis suppurativa with dorsal foot involvement: a case report

Hidradenitis suppurativa (HS) is a highly morbid chronic inflammatory skin disease resulting in painful and purulent lesions classically occurring in areas with a high density of apocrine glands such as the groin and axillae. This is the case of a 53-year-old male with medically refractory Hurley stage III HS affecting multiple anatomical sites including the dorsum of the right foot, an atypical location. Throughout his hospital course, he underwent a series of surgical excision and graft procedures to treat extensive HS lesions on various anatomical locations. In patients with a history of HS, mechanical stress may result in atypical lesion locations. In addition to the standard medical and surgical treatment, management should include optimizing nutritional parameters, smoking cessation, wound care and reducing friction and pressure at the affected area.

Further Histological and Cellular Characterization of Hidradenitis Suppurativa in 11 Patients

Background: Hidradenitis suppurativa is a chronic inflammatory skin disease, with significant morbidity secondary to its recurrent painful and exudative lesions. Given limited research on the cytoarchitecture of hidradenitis suppurativa, this study describes the microscopic structure and cell surface markers present in hidradenitis suppurativa tissue to better understand the disease and identify potential therapeutic targets. Methods: Skin biopsies of hidradenitis suppurativa lesions from patients who underwent surgical excision (n = 11) were compared with grossly normal-appearing perilesional skin (n = 5) and normal skin biopsies from unaffected individuals (n = 4). Histopathology and epidermal thickness were assessed using hematoxylin and eosin and picrosirius red staining, and CD3, a T-cell marker, and CD31 (PECAM), a vascular endothelial cell marker, were assayed using immunofluorescence. Data were analyzed and compared using analysis of variance and Student's t test. Results: Histological examination showed that hidradenitis suppurativa samples had a significantly thicker epidermal layer than normal skin (335.23 ± 165.01 µm vs 57.24 ± 18.43 µm, P = .005), extending into and engulfing the dermis. The hidradenitis suppurativa dermis had extensive cellular infiltration and aggregation as well as disorganized collagen. Immunofluorescence analysis revealed that, at the dermal level, hidradenitis suppurativa lesions had a significantly greater quantity of CD3⁺ (324.29 ± 139.28 vs 14.93 ±16.32, P < .0001) and CD31⁺ (322.15 ± 155.46 vs 2.84 ± 5.56, P < .0001) cells/mm² compared with normal skin samples. Conclusions: Hidradenitis suppurativa lesions have thicker epidermal layers, more dermal cellular infiltrate, and disorganized collagen fibers compared with normal skin. Furthermore, hidradenitis suppurativa dermis has a greater quantity of CD3⁺ and CD31⁺ cells than normal skin.

Factors Affecting Healing in the Treatment of Hidradenitis Suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic debilitating condition. Treatment of HS depends on disease stage, goals of care, access to care, and frequency of symptoms. We present our experience with surgical treatment for patients with HS.

METHODS

Patients were followed longitudinally for at least 2 years postsurgical intervention. Demographic data, participation in a multidisciplinary program, type of surgery, healing rates, and potential factors contributing to wound healing were retrospectively reviewed in all cases using multivariate analysis.

RESULTS

Two hundred forty-eight patients met the inclusion criteria with a total of 810 involved sites. Overall, 59% of patients had Hurley stage 3 disease at the time of surgery. Healing rates of 80% were observed in stages 1 and 2, and 74% were observed in stage 3. Hurley stage was not a significant predictor of healing (P = 0.09). Surgical treatment consisted of 38% incision and drainage, 44% excision without closure, and 17% excision with primary closure. Incisional and excisional treatments healed 78% and 79%, respectively, at 2 years. Primarily repaired defects (grafts and flaps) were 68% healed at 2 years. Observed healing rates were uniform regardless of the number of sites involved (P = 0.959). Participation in the multidisciplinary program was the strongest predictor of healing (78% vs 45%, P = 0.004). Sex, age, body mass index, tobacco use, diabetes, presurgery hemoglobin, and family history of HS were statistically not significant. Continuation of immune modulating therapy within 2 weeks of surgery was a predictor of reduced healing (odds ratio, 0.23; P = 0.004), whereas holding biologics for at least 2 weeks was not significant (odds ratio, 1.99; P = 0.146).

CONCLUSIONS

Participation in a multidisciplinary program is a strong predictor of long-term success when treating HS. Hurley score and number of involved sites did not correlate with successful healing after surgery. If taking biologics, we identified 2 weeks as an appropriate break from biologics before and after surgical intervention. Healing rates were highest with ablative procedures (incision and drainage, excision) alone.

Hidradenitis suppurativa and vasculitis: A case series and literature review of a rare association

Hidradenitis suppurativa is a chronic inflammatory skin disease with dysregulation of the immune system. Its pathophysiology is not clear, and it has been reported in association with various inflammatory disorders such as pyoderma gangrenosum, arthritis, familial Mediterranean fever and inflammatory bowel diseases. However, the co-existence of HS and vasculitis is exceptional and has not been investigated. We report on five patients with vasculitis that are followed in our centers: one with Takayasu’s arteritis, three with granulomatosis with polyangiitis and one with Behcet’s disease and compare them with those previously reported in the literature. A case series and literature review with key words of “vasculitis,” “hidradenitis suppurativa,” and “acne inversa” found only one previous report of hidradenitis suppurativa and cutaneous vasculitis and two with Behcet’s disease. Whereas the association of pyoderma gangrenosum and vasculitis is well-known, that with hidradenitis suppurativa is rarer. There may be some pathogenic continuum between hidradenitis suppurativa, pyoderma gangrenosum and vasculitis.

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

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

Langerhans cell histiocytosis: A great imitator

Langerhans cell histiocytosis (LCH) is an uncommon but serious inflammatory neoplasia that affects many organs, including the skin. Though uncommon, it should remain high on a clinician's differential diagnosis in treatment-resistant cases of conditions, such as seborrheic dermatitis, diaper dermatitis, arthropod bites, and many more. A thorough history nd physical examination for each patient can aid in the diagnosis; however, if clinically suspicious for LCH, a punch biopsy should be performed. Histologic evaluation of LCH is often enough to differentiate it from the many clinical mimickers. Characteristic findings include a histiocytic infiltrate with "coffee bean"-cleaved nuclei, rounded shape, and eosinophilic cytoplasm. Immunohistochemical stains, including CD1a, S100, and CD207 (langerin) are often needed for a definitive diagnosis. Electron microscopy also demonstrates the ultrastructural presence of Birbeck granules, but this is no longer needed due to immunohistochemical staining. Treatment is often necessary for LCH, if systemic involvement exists.

Review of imaging technologies used in Hidradenitis Suppurativa

BACKGROUND

Until recently, clinical assessment with manual palpation of the HS lesions was the primary means to detect HS lesions and their borders. In the past decade, there has been increased application of imaging technologies to HS patients, and it is reported that manual palpation consistently underestimates HS. Of the technologies, ultrasound (US) imaging has been the most efficacious and well-studied. In the present review, we will discuss the various imaging modalities that aid in detecting, managing, and treating HS.

MATERIALS AND METHODS

Non-invasive HS imaging technologies including ultrasound (US) imaging, magnetic resonance imaging (MRI), medical infrared thermography (MIT), positron emission topography (PET), and computed tomography (CT) were reviewed and compared through a review of the literature. PubMed, Google, and Google Scholar were utilized.

RESULTS

Of the 4 HS technologies reviewed, US imaging and MRI are the most established and useful non-invasive modalities utilized in HS patients. However, MIT may have potential to aid in the pre-operative and intra-operative surgical excision of HS lesions.

CONCLUSION

For imaging HS lesions, US imaging is the most well-characterized and has the greatest range of use, while MRI has a role in severe, anogenital HS lesions. MIT of HS lesions is a novel application and merits attention.