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Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease that is characterized by the formation of comedones, papules, nodules, abscesses and sinus tracts in the axillary, inframammary, groin, and gluteal areas. Up to 3.8% of the Canadian population has HS, though due to a lack of awareness of HS, many patients are initially misdiagnosed and do not receive adequate treatment early on in the disease course. Once a diagnosis of HS is made, developing an effective management plan can be a dilemma for many providers. There is significant variability in response to any given therapy within the HS patient population and many HS patients have other medical comorbidities which must be taken into consideration. The aim of this review is to provide a practical approach for all healthcare providers to diagnose and manage HS and its associated comorbidities. A sample electronic medical record template for HS management was developed by the Canadian Hidradenitis Suppurativa Foundation Executive Board and is intended for use in clinical settings. This will help to increase collaboration between primary healthcare providers, dermatologists, and other medical specialists and ultimately improve the quality of care that HS patients receive.

COVID-19 continues to pose a risk to patients with hidradenitis suppurativa (HS) due to the high prevalence of comorbidities associated with severe COVID-19 disease; we aimed to characterize perspectives on COVID-19 vaccination among HS patients. International respondents from 20 HSonline support groups were recruited to complete a voluntary, anonymous, online cross-sectional survey from 10/25-11/21/2021 to obtain perspectives from people with HS who may and may not access healthcare. We report higher rates of COVID-19 vaccine hesitancy amongst HS patients who expressed dissatisfaction with their dermatologic care.

Background There is limited information about mortality rates among patients with psoriasis and psoriatic arthritis (PsA) in North America and their change over the past 2 decades. Objective To compare all-cause and cause-specific mortality rates in patients with psoriasis to the general population in Ontario, Canada, from 1996 to 2016. Methods We conducted a population-based, retrospective cohort study of adult residents using administrative health data. All-cause and cause-specific standardized mortality rates, standardized mortality ratios, and excess mortality rates were calculated. Results 176,858 (2,524 deaths) patients with psoriasis and 15,430 (221 deaths) patients with PsA were identified in 2016. Patients with psoriasis and PsA had standardized excess mortality rates of 1.44 and 2.43 per 1000 population, respectively. Standardized mortality rates decreased by approximately 30% over the study period in both disease groups but remained significantly elevated compared to the general population. The leading causes of death in psoriasis and PsA patients were cancer, circulatory disease, and respiratory conditions. Limitations We were unable to classify patients according to disease severity. Conclusions Despite improvements in psoriasis treatment, the relative excess mortality, which may be related to risk factors for psoriatic disease, remained unchanged, with an average of approximately 1 to 2 extra deaths per 1,000 patients in 2016.

Background Limited data is available on the burden of dermatologic disease including disease distribution and providers of care. Research is needed to facilitate health care planning and improve patient care. Objectives To investigate the demographics and economics of the provision of dermatologic care in a universal health care system from fiscal year 2000 to 2016. Methods A retrospective population-based analysis was performed on physician billing claims for dermatologic conditions from April 1, 2000 to March 31, 2017. Data came from the province of Ontario’s universal health care plan claims records accessed through IntelliHealth. Results Dermatologic claims made up 3.6% of all physician claims, with a 20% increase seen over time. The cost of dermatologic claims increased by 70% between fiscal 2000 and 2016, with the average cost per claim increasing by 41%. However, the cost of dermatologic claims as a percentage of all health care claims experienced a decline from 3.5% in fiscal 2000 to 2.8% in fiscal 2016. Over the study period, family physicians submitted 56% to 62% of dermatologic claims, dermatologists 24% to 29%, pediatricians 3% to 4%, and internists 1%. Overall, internists billed the highest average cost per dermatologic claim ranging from $39 in 2000 to $60 in 2016, followed by pediatricians at $33 to $58, dermatologists at $28 to $39, and family physicians at $23 to $30. Conclusions The demographic and economic burden of dermatologic disease is changing over time, with implications for health care planning, advancing medical education, and patient care.

OBJECTIVE Information about the prediagnosis period in psoriatic arthritis (PsA) is limited. The present study was undertaken to compare health care utilization related to musculoskeletal issues during a 5-year period prior to the diagnosis of PsA versus that of subjects with no prior inflammatory arthritis within a primary care setting. METHODS We conducted a population-based, matched cohort study using electronic medical records and administrative data in Ontario, Canada. Age- and sex-matched cohorts of PsA patients and comparators from the same family physicians were assembled. Comparators were not allowed to have prior spondyloarthritis, ankylosing spondylitis, or rheumatoid arthritis billing code diagnoses. The study outcomes included health care utilization and costs related to nonspecific musculoskeletal issues during a 5-year period prior to the index date. RESULTS We studied 462 PsA patients and 2,310 matched comparators. The odds ratio (OR) related to visiting a primary care physician for nonspecific musculoskeletal issues in patients with PsA was 2.14 (95% confidence interval 1.73-2.64) in the year immediately preceding the index date and was similarly elevated up to 5 years prior. The OR related to using other musculoskeletal-related health care services, including musculoskeletal specialists visits, joint injections, joint imaging, and emergency department visits, was higher in PsA as early as 5 years preceding the index date. Total and musculoskeletal-related health care costs prior to the index date were higher for patients with PsA versus comparators. CONCLUSION A prodromal PsA phase characterized by nonspecific musculoskeletal symptoms may exist. Further study is needed to determine if this represents a window for earlier diagnosis of PsA.

Complete visualization of lesions is critical for the accurate diagnosis and management of dermatological diseases. Currently, the most readily available technologies used by dermatologists include dermoscopy and photography. Nevertheless, ultrasound has emerged as a useful non-invasive modality in dermatology, which can be added to the clinical examination supporting an early and more accurate diagnosis. Moreover, there are significant technological advances in recent years, such as the development of handheld devices and ultra-high frequency probes that have expanded the integration of ultrasound into daily dermatology practice. In this article, we reviewed the most common applications of ultrasound in the field of dermatology.

Background: Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphoma (CTCL). There is currently no cure for CTCL, and treatment is aimed at limiting disease progression. This study evaluated the efficacy and tolerability of alitretinoin in CTCL management. Methods: A retrospective, multicenter study was conducted on CTCL patients treated with alitretinoin as a primary agent or in combination with standard therapies. Results: Forty-eight patients with MF ( n = 40) and SS ( n = 8) with a median age of 59.7 years (±14.3) were eligible for study inclusion. Treatment response data were evaluated in 40 patients and safety in 42 patients. 40.0% of the patients had early-stage, 43.8% had advanced-stage CTCL, and in 16.7% of patients there was insufficient information for staging. 40.0% (16/40) of the patients achieved a complete or partial response, whereas 47.5% (19/40) achieved stable disease, 12.5% (5/40) had progressive disease, and there were no cases of disease relapses in responders. Both early and advanced stages of CTCL were responsive to alitretinoin as a primary or combined modality. Alitretinoin was well tolerated, and 64.3% (27/42) of patients did not report any side effects. The most commonly observed side effect was hypertriglyceridemia. Conclusions: This retrospective analysis supports the efficacy and safety of alitretinoin in clearing skin disease and preventing disease progression in CTCL as a monotherapy or in combination with standard therapies.

BACKGROUND Down syndrome (DS) has been associated with cardiovascular, gastrointestinal, and immune-related abnormalities. Several dermatologic conditions, including hidradenitis suppurativa, have also been found to be associated with DS. OBJECTIVE The objective of this study was to characterize the prevalence, presentation, and unique features of dermatologic disorders associated with DS. METHODS Electronic searches of EMBASE (via Ovid), MEDLINE (via Ovid), and Web of Science databases were conducted on December 14, 2020. Observational studies including case reports of patients with DS presenting with concomitant primary dermatologic disorder were included. RESULTS This systematic review captured 40 observational studies and 99 case reports, including 10 observational studies that examined the prevalence of common skin disorders in patients with DS. The most common dermatologic conditions reported includes atopic dermatitis (8 studies, n=180; 19.7% mean prevalence), hidradenitis suppurativa (15, n=478; 3.2%), ichthyosis (4, n=16; 4.7%), lichen nitidus (6, n=6; 1.1%), psoriasis (21, n=65; 4.8%), alopecia areata (27, n=253; 7.4%), vitiligo (8, n=40; 4.4%), onychomycosis (3, n=198; 24.7%), calcinosis cutis (14, n=15), connective tissue nevi (6, n=6), dermatofibroma (3, n=3), melanoma (3, n=3), syringomas (14, n=182; 21.2%), and elastosis perforans serpiginosa (19, n=24; 0.5%). CONCLUSIONS Our results indicate an increased prevalence of common cutaneous disorders in patients with DS, particularly infectious, inflammatory, autoimmune, and connective tissue conditions. Current guidelines for the screening, general management, and use of systemic immunomodulatory agents in this patient population are lacking. Patients with DS would benefit from screening for dermatologic disorders not otherwise regularly performed for earlier diagnosis and treatment. CLINICALTRIAL PROSPERO International Prospective Register of Systematic Reviews CRD42021226295; https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=226295

BACKGROUND Hidradenitis suppurativa (HS) is a painful inflammatory disorder that confers significant distress to patients, with surgery as an integral treatment modality. OBJECTIVE To inform improvements in care, patterns in HS surgery were assessed. METHODS A retrospective population-based analysis was performed on Ontario billing claims for HS surgery across a period of 10 years from January 1, 2008 to December 31, 2017. HS surgery was defined as the excision of inguinal, perineal, or axillary skin and sweat glands for hidradenitis. The top 5 billing specialties, including general and plastic surgery, were analyzed. The total number of procedures performed as well as the number performed per physician were investigated. Patient and physician locations were compared. RESULTS A total of 7195 claims for the excision of inguinal, perineal, or axillary skin and sweat glands for HS were submitted across the study period. Annual HS surgery claims showed an increasing trend across 10 years, ranging between 4.9 and 5.8 per 100,000 population. However, overall, for every additional year, the number of claims per 100,000 population only increased slightly, by 0.03 claims. The number of providers steadily decreased, ranging between 1.7 and 1.9 per 100,000, with approximately twice as many general than plastic surgeons. However, again overall, for every additional year, the number of providers per 100,000 population decreased slightly, by 0.002 physicians. The mean annual number of procedures per physician rose from 2.8 to 3.1. In rural areas, analyzed per claim, general surgeons performed the majority of surgeries (1318/2003, 65.8%), while in urban areas, surgeries were more equally performed by general (2616/5192, 50.4%) and plastic (2495/5192, 48.1%) surgeons. Of HS surgery claims, 25.7%-35.9% were provided by a physician residing in a different area than the patient receiving care. CONCLUSIONS No significant improvements in access to HS surgery were seen across the study period, with access potentially worsening with annual HS claims rising overall and number of providers decreasing, with patients travelling further to access surgery. System barriers across the continuum of HS diagnosis and management must be evaluated to improve access to surgical care.

Squamous cell carcinoma (SCC) can present as a rare complication of longstanding hidradenitis suppurativa (HS) lesions. Limited data exist on characteristics and outcomes of SCC development within HS lesions. The purpose of this review is to conduct a literature review of previously reported cases of SCC development in pre-existing HS lesions. EMBASE and MEDLINE searches were conducted in OVID on June 25, 2020, to yield 59 studies. Of the 95 patients (mean age: 52.9 years) who developed a total of 122 SCCs within HS lesions, the majority were males (77.9%, n = 74/95). The most common sites of SCC were the gluteal region (47.5%, n = 58/122), the perianal region (18.9%, n = 23/122), and the genitals (13.9%, n = 17/122). The mean duration between HS onset and SCC development was 25.5 years. Of the patients that had outcomes reported, 54.0% (n = 34/63) experienced SCC metastasis, 43.1% (n = 28/65) experienced SCC recurrences, and 58.7% (n = 44/75) experienced a mortality outcome. The most common documented reasons for death included metastasis (34.1%, n = 15/44) and sepsis (13.6%, n = 6/44). Patients with longstanding HS lesions can develop SCCs with a high rate of metastasis and mortality. Thus, chronic HS lesions, especially in the gluteal, perianal, genital, and perineal regions, should be monitored regularly for timely SCC diagnosis and management.

High-quality dermatology patient registries often require considerable time to develop and produce meaningful data. Development time is influenced by registry complexity and regulatory hurdles that vary significantly nationally and institutionally. The rapid emergence of the coronavirus disease 2019 (COVID-19) global pandemic has challenged health services in an unprecedented manner. Mobilization of the dermatology community in response has included rapid development and deployment of multiple, partially harmonized, international patient registries, reinventing established patient registry timelines. Partnership with patient organizations has demonstrated the critical nature of inclusive patient involvement. This global effort has demonstrated the value, capacity, and necessity for the dermatology community to adopt a more cohesive approach to patient registry development and data sharing that can lead to myriad benefits. These include improved utilization of limited resources, increased data interoperability, improved ability to rapidly collect meaningful data, and shortened response times to generate real-world evidence. We call on the global dermatology community to support the development of an international federation of patient registries to consolidate and operationalize the lessons learned during this pandemic. This will provide an enduring means of applying this knowledge to the maintenance and development of sustainable, coherent, and impactful patient registries of benefit now and in the future.

Hidradenitis suppurativa (HS) is a common inflammatory disorder characterized by recurrent, painful, and malodorous abscesses and nodules predominantly in skin folds. HS is associated with substantial morbidity and poor quality of life. There are no curative therapies, and the only approved biologic drug has variable efficacy and requires high doses, making adjunct treatments crucial. An important risk factor for disease severity is obesity. Our primary objective was to conduct a systematic review examining weight loss and dietary interventions, in HS. Our secondary objective was to examine nutritional supplements in HS.A systematic literature search was conducted using Medline, EMBASE, and the Cochrane Database. We included all study types in adults (>18 years), with a minimum sample size of 5, examining the effects of any dietary or weight loss intervention on HS severity. Two authors screened n = 1279 articles of which 9 met inclusion criteria. All included studies were observational and all interventions were associated with various measures of decreased HS severity. Patient-controlled weight loss and bariatric surgery were associated with HS regression, though a subset of patients with significant increase in panniculi experienced exacerbations and required excision of excess skin. Diets demonstrating benefit eliminated dairy and brewer’s yeast. Nutritional supplements including zinc gluconate, vitamin D, and riboflavin had a suppressive, rather than curative, effect on HS lesions in single studies. Overall, the reviewed interventions show promise as potential adjunct treatments in a HS management plan. Prospective randomized controlled trials should validate these findings.

Mycosis fungoides (MF) and Sézary syndrome (SS) are chronic, progressive primary cutaneous T-cell lymphomas (CTCLs) for which there are no curative treatments. Skin-directed therapies, such as phototherapy, radiation therapy, or topical nitrogen mustard, provide only short-term remissions. Numerous attempts with different chemotherapeutic regimes failed to achieve meaningful clinical responses. Immunotherapy seems to be a promising avenue to achieve long-term disease control in CTCL. There is compelling evidence indicating that MF and SS are immunogenic lymphomas, which can be recognized by the patient’s immune system. However, CTCL uses different strategies to impair host’s immunity, eg, via repolarizing the T-cell differentiation from type I to type II, recruiting immunosuppressive regulatory T-cells, and limiting the repertoire of lymphocytes in the circulation. Many currently used therapies, such as interferon-α, imiquimod, extracorporeal phototherapy, and allogeneic bone marrow transplant, seem to exert their therapeutic effect via activation of the antitumor cytotoxic response and reconstitution of the host’s immune system. It is likely that novel immunotherapies such as immune checkpoint inhibitors, cancer vaccines, and chimeric antigen receptor-T cells will help to manage CTCL more efficiently. We also discuss how current genomic techniques, such as estimating the mutational load by whole genome sequencing and neoantigen calling, are likely to provide clinically useful information facilitating personalized immunotherapy of CTCL.

Hidradenitis suppurativa is a severe and debilitating dermatologic disease. Clinical management is challenging and consists of both medical and surgical approaches, which must often be combined for best outcomes. Therapeutic approaches have evolved rapidly in the last decade and include the use of topical therapies, systemic antibiotics, hormonal therapies, and a wide range of immunomodulating medications. An evidence-based guideline is presented to support health care practitioners as they select optimal medical management strategies and is reviewed in this second part of the management guidelines. A therapeutic algorithm informed by the evidence available at the time of the review is provided.

The association between alopecia areata (AA) and autoimmune thyroid diseases (AITD) has been suggested; however, the chronological relationship between AA and AITD remains elusive. A systematic review and meta-analysis were conducted to assess the association between AA and AITD focusing on the prevalence of thyroid antibodies, thyroid diseases and serological thyroid dysfunctions, respectively. Data collection was performed in October 2018 by searching for articles in two electronic databases: Medline and Embase. Case-control, cohort and cross-sectional studies were included. Meta-analysis of studies eligible for quantitative synthesis was performed to estimate pooled odds ratios of thyroid antibodies; thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (TG-Ab), diagnosed thyroid diseases and serological thyroid dysfunctions. Four hundred and eighty nine research papers were identified and 17 studies with 262 581 patients and 1 302 655 control subjects were included for quantitative synthesis. AA was significantly associated with both TPO-Ab and TG-Ab. In comparison, there was no significant association between AA and diagnosed hypothyroidism or hyperthyroidism and serological hypothyroidism or hyperthyroidism. In conclusion, AA is significantly associated with the existence of thyroid antibodies rather than with clinical or laboratory thyroid abnormality. Lack of long-term follow-up data is a limitation of the existing published work. Our findings do not support routine screening of thyroid diseases for asymptomatic AA patients but highlight the potential future risk of AITD particularly in severe and refractory AA.

The 3(rd) Annual Symposium on Hidradenitis Suppurativa Advances (SHSA) took place on October 12–14, 2018 at the Women’s College Hospital in Toronto, Ontario, Canada. This symposium was a joint meeting of the Hidradenitis Suppurativa Foundation (HSF) founded in the USA, and the Canadian Hidradenitis Suppurativa Foundation (CHSF). This cross-disciplinary meeting with experts from around the world was an opportunity to discuss the most recent advances in the study of hidradenitis suppurativa pathogenesis, epidemiology, classification, scoring systems, radiologic diagnosis, treatment approaches, and psychologic assessment. Two special sessions this year were HS as a systemic disease and HS management guidelines. There were focused workshops on wound healing and ultrasound. There were two sessions primarily for patients and their families in the HS School program: one workshop focused on mindfulness, and the second involved discussion among clinicians and patients about various disease aspects and the latest management. To facilitate networking between clinical and research experts and those early in their career, a mentoring breakfast was held.

Background Mycosis fungoides (MF) typically has a CD4+ CD8- T-cell phenotype. Rare cases of CD4- CD8+ , CD4- CD8- , or CD4+ CD8+ immunophenotypes have been described. Little is known about the impact of MF immunophenotypes on disease behavior. Methods We conducted a retrospective cohort study to review all cases of MF from 2007 to 2017 from Sunnybrook Health Sciences Centre, Toronto, Canada. CD4+ CD8- (Group 1) was compared to the three less common subtypes (Group 2) with respect to stage at diagnosis, progression, and transformation. Potential confounding factors (demographic, clinical, and laboratory parameters) were assessed. Results A total of 160 patients with confirmed MF were analyzed, including 126 CD4+ CD8- MF (79%), 26 CD4- CD8+ MF (16%), six CD4+ CD8+ MF (4%), and two CD4- CD8- MF (1%). Both groups were similar with respect to demographics and laboratory parameters at the time of diagnosis. There was no difference between patients with late stage disease (10% vs. 9%) for groups 1 and 2, respectively (P = 0.901). There was no statistically significant difference either in 5-year progression (27.7% vs. 23.5%, P = 0.283) or transformation (16.2% vs. 17.3%, P = 0.350) estimates. We did find that atypical immunophenotypes presented with different clinical morphologies and were less likely to require systemic therapy. Conclusion Our large cohort study indicates that atypical MF immunophenotypes do not seem to influence prognosis. Hypopigmented MF was more frequent in the CD4- CD8+ group while folliculotropic MF was exclusively seen in the CD4+ CD8- group. We believe that cases of CD8+ MF with aggressive behavior described in the literature represent misclassified primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma. The small number of patients included in the study is a limiting factor.

Solid organ transplant recipients have a high risk of keratinocyte carcinoma (non-melanoma skin cancer). Consensus-based transplant guidelines recommend annual dermatological examination but the impact on skin cancer-related outcomes is unclear. We conducted a population-based, retrospective, inception cohort study using administrative health databases in Ontario, Canada to evaluate the association between adherence to annual dermatology assessments (time-varying exposure) and keratinocyte carcinoma-related morbidity and mortality after transplantation. The primary outcome was the time to first advanced (highly morbid or fatal) keratinocyte carcinoma. Among 10 183 adults receiving their first transplant from 1994 to 2012 and followed for a median of 5.44 years, 4.9% developed an advanced keratinocyte carcinoma after transplant. Adherence to annual dermatology assessments for at least 75% of the observation time after transplant was associated with a 34% reduction in keratinocyte carcinoma-related morbidity or death compared with adherence levels below 75% (adjusted hazard ratio 0.66, 95% CI 0.48-0.92). Adherence levels were universally low (median proportion of time spent in adherence 0%, inter-quartile range 0-27%). Only 45% of transplant recipients had ever seen a dermatologist and 2.1% were fully adherent during the entire observation period. Strategies are needed to improve adherence rates in order to help decrease long-term morbidity after transplant.

Hidradenitis suppurativa (HS) is a chronic and often debilitating inflammatory condition characterized by frequent nodules, abscesses, sinus tracts, and scars impacting the intertriginous areas. Many patients with HS often report limited treatment success and symptom coverage with conventional therapies. Recent studies have reported the widespread use of complementary and alternative medicine (CAM) among patients with HS. In this study, our aim was to examine current physician practice patterns, opinions, and comfort with recommending CAM. Our results indicate that provider comfort and opinions on CAM varied based on the provider's experiences, demographics, and the CAM modality itself. Overall, nearly two-thirds (n=30, 61.2%) of respondents agreed that CAM and conventional medicine were more effective together than either alone. Meanwhile, 44.9% (n=22) of respondents routinely recommend CAM while 64.6% (n=31) of respondents reported that they are routinely asked about CAM. The majority (n=41, 83.7%) of respondents indicated a lack of scientific evidence in the medical literature as a barrier to recommending CAM along with efficacy concerns (n=34, 69.4%) and ability to recommend reputable CAM products (n=32, 65.3%) and practitioners (n=32, 65.3%). Future investigations are warranted to establish a better understanding of the efficacy and benefit of CAM methods in conjunction with conventional methods. This article is protected by copyright. All rights reserved.

Background: Several studies report a high prevalence of inflammatory arthritis among hidradenitis suppurativa (HS) patients. Objectives: To study the association between HS and inflammatory arthritis. Methods: The systematic review and meta-analysis were performed according to the PRISMA guidelines to identify the association between HS and inflammatory arthritis, spondyloarthritis, ankylosing spondylitis (AS), and rheumatoid arthritis (RA). Results: Seven studies were entered in the analysis, with 200,361 HS patients and 385,599 controls. Pooled analysis illustrated a significantly increased risk of inflammatory arthritis in HS patients compared to controls (odds ratio [OR] 3.44; 95% confidence interval [CI] 1.92–6.17). There was also a statistically significant association between HS and spondyloarthritis (OR 2.10; 95% CI 1.40–3.15), and between HS and AS (OR 1.89; 95% CI 1.14–3.12). Moreover, pooled analysis showed a statistically significant association between HS and RA (OR 1.96; 95% CI 1.28–2.98). Conclusions: Our findings show that HS patients have a 3-fold increased risk of developing inflammatory arthritis. HS patients are specifically at a higher risk for spondyloarthritis, its subtype AS, and RA.

Background Hidradenitis suppurativa (HS) is associated with comorbidities that contribute to poor health, impaired life quality, and mortality risk. Objective To provide evidence-based screening recommendations for comorbidities linked to HS. Methods Systematic reviews were performed to summarize evidence on the prevalence and incidence of 30 comorbidities in patients with HS relative to the general population. The screening recommendation for each comorbidity was informed by the consistency and quality of existing studies, disease prevalence, and magnitude of association, as well as benefits, harms, and feasibility of screening. The level of evidence and strength of corresponding screening recommendation were graded by using the Strength of Recommendation Taxonomy (SORT) criteria. Results Screening is recommended for the following comorbidities: acne, dissecting cellulitis of the scalp, pilonidal disease, pyoderma gangrenosum, depression, generalized anxiety disorder, suicide, smoking, substance use disorder, polycystic ovary syndrome, obesity, dyslipidemia, diabetes mellitus, metabolic syndrome, hypertension, cardiovascular disease, inflammatory bowel disease, spondyloarthritis, and sexual dysfunction. It is also recommended to screen patients with Down syndrome for HS. The decision to screen for specific comorbidities may vary with patient risk factors. The role of the dermatologist in screening varies according to comorbidity. Limitations Screening recommendations represent one component of a comprehensive care strategy. Conclusions Dermatologists should support screening efforts to identify comorbid conditions in HS.

Background Hidradenitis suppurativa (HS), characterized by inflammatory nodules, sinus tracts, and abscesses, has been linked to several factors, including immune dysfunction and obesity, which are thought to contribute to its development. Several follicular disorders have also been associated with Down syndrome (DS), a common chromosomal disorder, including HS, although studies on this topic are limited. Objectives To characterize HS in Down syndrome patients and to further examine the association between HS and DS compared to HS patients without DS. Methods We systematically searched MEDLINE, Embase, Web of Science, and CENTRAL electronic databases from their dates of conception to February 2020. Random-effects meta-analyses were performed analyzing (a) HS characteristics between DS and non-DS participants, and (b) prevalence or association between HS and DS compared to non-DS individuals. Results Twelve studies were included in this systematic review, with a total of 358 participants presenting with both HS and DS. Pooled analysis of mean differences between DS and non-DS participants presenting with HS found a significantly younger age of HS symptom onset for DS patients (-6.24; 95% CI, -10.01--2.24). A meta-analysis examining the association between HS and DS found a significantly increased likelihood of HS in DS patients (OR 9.61; 95% CI, 5.70-16.20). Conclusions Our findings suggest an association between HS and DS, with DS patients suffering from an earlier onset of HS symptoms compared to non-DS patients.

Background: Changes in the practice patterns and demographics of Canadian dermatologists remain largely unknown and would be helpful in assessing the future practice of dermatology across Canada. Objective: To assess changes in the population of Ontario dermatologists over time and the factors that influence their practice patterns, caseload, and the procedures they perform. Methods: A retrospective population-based analysis was performed using comprehensive administrative data on Ontario Health Insurance Plan insured dermatology visits and procedures from April 1, 2009, to March 31, 2015. Results: The number of dermatologists practicing in Ontario per 100 000 people increased from 1.52 (2009) to 1.62 (2014). During this period, the proportion of female dermatologists increased from 40% to 47%, and the proportion of male dermatologists decreased from 60% to 53%. The mean number of patient visits per dermatologist decreased from 6323 (2009) to 5877 (2014). Females saw a decrease from 4818 to 4181 visits, and males remained constant at 7274 to 7265 visits. Middle career dermatologists had more patient visits compared to those in their early or late career. A rural practice was associated with more patient visits compared to an urban one. The proportion of dermatologists providing nonemergency in-hospital patient services declined. The number of biopsies and malignant excisions performed increased. Conclusions: The number of dermatologists at the population level increased and the number of patient visits per dermatologist decreased. Career stage, physician sex, and practice location all affect the practice of dermatology. Future studies to assess underlying factors for these observations would be of value.

Hidradenitis Suppurativa (HS) is a chronic debilitating skin condition that impairs the productivity and the quality of patients` lives. HS has recently drawn lots of attention among scholars to further expand their knowledge but it still loads with uncertainties and gaps to be explored. This publication addresses these uncertainties, and provides a road-map for researchers, scholars and clinicians from different disciplines for their future studies about HS. This is a proceeding report of the first Symposium on Hidradenitis Suppurativa Advances (SHSA), and it reviews the scientific sessions about the epidemiology, pathophysiology, presentations, and management of HS. This symposium was a great opportunity for experts in the HS field to exchange their knowledge, and improve their mutual understanding of this disease.

Few studies have reported the physical complications among Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) survivors. The aim of this study was to comprehensively characterize the physical complications among SJS/TEN survivors and to learn about patients’ perspectives of surviving SJS/TEN. SJS/TEN survivors older than 18 years of age were assessed by different methods: a medical interview; a questionnaire assessing patients’ perspectives; thorough skin, oral mucous membrane, and ophthalmic examinations; and a retrospective assessment of medical records. Our cohort consisted of 17 patients with a mean time of 51.6 ± 74.7 months (median 9, range 1–228) following SJS/TEN. The most common physical complications identified in the medical examination were post-inflammatory skin changes (77%), cutaneous scars (46%), dry eyes (44%), symblepharon, and chronic ocular surface inflammation (33% each). Novel physical sequelae included chronic fatigue (76%) and pruritus (53%). We also found a novel association between the number of mucous membranes affected in the acute phase of SJS/TEN and hair loss during the 6 months following hospital discharge; hair loss was reported in 88% of the group of patients who had three or more mucous membranes affected versus 29% of patients who had less than three mucous membranes involved (p = 0.0406). Following hospital discharge due to SJS/TEN, 59% of patients were followed by a dermatologist, although 88% had dermatological complications; 6% were followed by an ophthalmologist, even though 67% had ophthalmological complications; and 6% of female survivors were followed by a gynecologist, even though 27% had gynecological complications. Survivors of SJS/TEN suffer from severe physical complications impacting their health and lives that are mostly under recognized and not sufficiently treated by medical professionals.

Hidradenitis suppurativa (HS) is a painful chronic inflammatory disease with a prevalence between 1 and 4% of general population. The pathogenesis of HS long eluded scientists, but growing evidence suggests that it is a consequence of inflammatory dysregulation. Recent studies suggest that dysregulated immune response to skin flora and overexpression of inflammatory cytokines leads to chronic skin inflammation seen in HS. Macrophages are the most numerous inflammatory cells found in HS infiltrates and release numerous pro-inflammatory cytokines such as IL-23, and IL-1β and TNF-α, exacerbating the inflammation and contributing to the pathogenesis of HS. Furthermore, in HS, there is dysregulated function of other immune players closely associated with macrophage function including: matrix metalloproteases (MMP) 2 and 9 overexpression, toll-like receptor upregulation, impaired Notch signalling, NLRP3 inflammasome upregulation, and dysregulated keratinocyte function. Lifestyle factors including obesity and smoking also contribute to macrophage dysfunction and correlate with HS incidence. The overexpression of pro-inflammatory cytokines and subsequent efficacy of anti-cytokine biologic therapies highlights the importance of managing macrophage dysfunction. Future therapies should target key molecular drivers of macrophage dysfunction such as TLR2 and NLRP3 overexpression.

Background: Hidradenitis suppurativa (HS) is a painful, debilitating, and poorly understood condition, which is suboptimally diagnosed, managed, and treated. Evidence supporting various treatment modalities is sparse. Objectives: To incorporate scientific evidence and expert opinions to develop useful guidance for the evaluation and management of patients with HS. Methods: An expert panel of Canadian dermatologists and surgeons developed statements and recommendations based on available evidence and clinical experience. The statements and recommendations were subjected to analysis and refinement by the panel, and voting was conducted using a modified Delphi technique with a prespecified cutoff agreement of 75%. Results: Ten specific statements and recommendations were accepted by the expert panel. These were grouped into 4 domains: diagnosis and assessment, treatment and management, comorbidities and a multidisciplinary approach, and education. Conclusions: These statements and recommendations will serve to increase awareness of HS and provide a framework for decisions involving diagnosis and management. Evidence suggests that antibacterial and anti–tumour necrosis factor therapies are effective in the treatment of HS. This is supported by the clinical experience of the authors. Further clinical research and the establishment of multidisciplinary management teams will continue to advance management of HS in Canada.

The management of hidradenitis suppurativa (HS), a chronic inflammatory skin disease, deserves special consideration in the context of the Coronavirus 2019 (COVID‐19) pandemic. A new Global Hidradenitis Suppurativa COVID‐19 Registry has been developed to capture data on risks, clinical course, and outcomes of COVID‐19 in HS patients. Caused by the virus SARS‐CoV‐2 (severe acute respiratory syndrome coronavirus‐2), COVID‐19 is an easily transmissible disease which, in its most severe form, is characterized by respiratory failure and multiple organ dysfunction triggered by a cytokine storm response that predominates in older adults and those with significant comorbidities.

Objectives.We assessed the accuracy of case definition algorithms for psoriasis and psoriatic arthritis (PsA) in health administrative data and used primary care electronic medical records (EMR) to describe disease and treatment characteristics of these patients.Methods.We randomly sampled 30,424 adult Ontario residents from the Electronic Medical Record Primary Care database and identified 2215 patients with any possible psoriatic disease–related terms in their EMR. The relevant patient records were chart abstracted to confirm diagnoses of psoriasis or PsA. This validation set was then linked to health administrative data to assess the performance of different algorithms for physician billing diagnosis codes, hospitalization diagnosis codes, and medications for psoriatic disease. We report the performance of selected case definition algorithms and describe the disease characteristics of the validation set.Results.Our reference standard identified 1028 patients with psoriasis and 77 patients with PsA, for an overall prevalence of 3.4% for psoriasis and 0.3% for PsA. Most patients with PsA (66%) had a rheumatology-confirmed diagnosis, while only 30% of the patients with psoriasis had dermatology-confirmed diagnosis. The use of systemic medications was much more common with PsA than with psoriasis. All algorithms had excellent specificity (97–100%). The sensitivity and positive predictive value were moderate and varied between different algorithms (34–72%).Conclusion.The accuracy of case definition algorithms for psoriasis and PsA varies widely. However, selected algorithms produced population prevalence estimates that were within the expected ranges, suggesting that they may be useful for future research purposes.