Research

Call to Accelerate HS Research & Improve Care

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Moving Beyond Burden

There is a dearth of high-level evidence guiding our understanding of the epidemiology, pathophysiology, and treatment of hidradenitis suppurativa (HS). Despite an estimated prevalence of 1% in Western populations and quality of life impairment often exceeding other chronic skin diseases, annual HS-related publications lag far behind annual publications for other common and rare skin diseases (Figure, A).1-5 Federal funding to study HS wanes in comparison to funding for other chronic cutaneous dermatoses, with only 0.1% of the National Institute of Arthritis and Musculoskeletal and Skin Diseases total research funds for skin diseases dedicated to HS (Figure, B).6 By December 31, 2018, only 17 clinical trials dedicated to HS had been completed in the United States and there is only 1 US Food and Drug Administration (FDA)-approved therapy for HS, compared with numerous trials and nearly a dozen currently FDA-approved systemic medications for psoriasis. The paucity of HS medical knowledge and effective therapies have contributed to patient distrust of the medical community and subsequent reluctance to seek medical care. Partnership with patients in research and clinical care is desperately needed to meaningfully improve the lives of people suffering with HS.

Publications and National Institutes of Health (NIH) Support for Hidradenitis Suppurativa (HS) vs Other Dermatologic Conditions

A, Number of annual PubMed citations for HS lags behind that of other prevalent and rare immune-mediated skin diseases (1945-2018), search date January 31, 2019. B, NIH has awarded 9 grants for HS research totaling $865 321, including 2 career development awards, 1 R03 research grant, and intramural research programs. By comparison, 4443 grants for psoriasis research totaled $1.42 billion in NIH funds. The National Institute of Arthritis and Musculoskeletal and Skin Diseases has now developed funding opportunities specifically for HS (PA-18-718 and PA-18-719). Total cumulative NIH funds awarded for 6 immune-mediated skin diseases research determined by NIH RePORTER database, search date February 4, 2019.

In recent years, the evidence for the tremendous burden of HS has been mounting. We now have retrospective data from large numbers of patients with HS extending our knowledge about comorbidity burden as highlighted in 3 recent JAMA Dermatology publications. In this issue, Chen and Chi7 performed a meta-analysis of 8 original case-control, cross-sectional, and cohort studies examining the association between HS and inflammatory bowel disease (IBD). They report that patients with HS had significantly increased odds of Crohn disease (pooled odds ratio [OR], 2.12; n = 91 917) and ulcerative colitis (pooled OR, 1.51; n = 39 497). Two case-control studies demonstrated an increased odds of IBD in HS (ORs, 2.16 and 10.0; n = 1642), whereas 1 cohort study of 14 136 participants found that IBD was 5.6 times more common in patients with HS than in the general population. These epidemiologic findings support data suggesting that there may be shared pathogenic mechanisms through immune dysregulation, and highlight the need for gastrointestinal symptom screening guidelines for patients with HS.

Systemic associations with HS extend beyond IBD and greatly affect the overall health and mortality of patients with the disease. In a recent study published in JAMA Dermatology, Reddy et al used the Charlson Comorbidity Index (CCI), an instrument that predicts mortality based on a range of comorbid conditions, to retrospectively assess comorbidity burden in 5306 patients with HS from a large US claims data set. Based on their analyses, patients with HS have a significantly higher mean CCI score (CCI = 1.95) than age-, sex-, and race- matched cohorts of patients with psoriasis (CCI = 1.47) and control (CCI = 0.95) patients.8 Patients with HS with a CCI score of 5 or greater had 4.97 times greater odds of 5-year mortality compared with those with a score of 0. These data support the prevalence of comorbid diabetes in HS while also revealing previously unrecognized associated life-threatening chronic comorbidities that are key to shaping our assessment and treatment of this patient population.

A third study in the journal is a recent systematic review and meta-analysis conducted by Machado et al of 10 original studies examining psychological comorbidities associated with HS. The authors reported that the prevalence of depression and anxiety across 40 307 patients with HS was 16.9% and 4.9%, respectively. The odds of depression in patients with HS compared with the general population was 1.84. These data, in combination with previously reported alarming data on completed suicides in the HS patient population (hazard ratio = 2.42),10 emphasize the urgent need for recognition and management of psychological comorbidities in patients with HS.

Findings such as these from large data sets and meta-analyses have been critical in informing HS comorbidity burden but are limited by their retrospective design and inability to investigate the complex relationships between comorbidities and HS disease severity and progression. In addition, guidance on how to translate these findings into clinical practice is lacking. Although the 2019 North American HS management guidelines11,12 are an important step in synthesizing existing data and guiding practitioners in HS treatment, the recommendations on comorbidity management are brief and expose the need for dedicated guidelines for HS comorbidity screening and referral to appropriate partners to reduce morbidity and mortality.

Furthermore, there is an urgent need for the generation of new knowledge to advance the field and improve care of patients with HS. Prospective clinical studies that deepen our understanding of HS disease characteristics and clinical course are needed to identify prognostic factors, understand phenotypic heterogeneity, and assess long-term outcomes and adverse effects of therapies. Translational studies aimed at uncovering disease etiology, developing biomarkers and predictors of treatment response, and identifying therapeutic targets are necessary to guide development of novel therapies and improve care of people with HS.

Collaborative efforts like the multi-institutional Hidradenitis Suppurativa Prospective Observational Registry and Biospecimen Repository (HS PROGRESS) have been developed in direct response to this critical need. Designed as a powerful partnership between investigators and patients, HS PROGRESS uses validated and expert consensus-derived objective and subjective measures to systematically collect longitudinal clinical data and biospecimens from patients with HS in all stages of disease to accelerate much-needed understanding of HS. Multi-institutional collaborative consortiums such as this are a key first step in accumulating important preliminary data and providing resources and infrastructure to acquire funding, generate high-level evidence, and develop novel therapies for HS. Furthermore, by facilitating clinical trials and research participation opportunities for consenting participants, HS PROGRESS may also play an important role in mending the fractured relationship between the HS patient population and medical communities.

Now that we are beginning to understand the true and tremendous impact of HS in terms of prevalence, quality of life impairment, and comorbidity burden, we must extend our knowledge to understand how to best care for patients. Multi-institutional collaborative consortiums that harness and grow relationships between patients and the medical community have the potential to powerfully accelerate science and advance care for even the most neglected diseases, and thereby meaningfully improve the lives of people with HS.

Corresponding Author: Haley B. Naik, MD, MHSc, Department of Dermatology, University of California, San Francisco, 2340 Sutter St, MC 0808, San Francisco, CA 94143-0808 (haley.naik@ucsf.edu).

Published Online: July 10, 2019. doi:10.1001/jamadermatol.2019.1105

Conflict of Interest Disclosures: Dr Lowes has received fees for participating in advisory boards for AbbVie and Janssen, and consulting fees from Incyte, BSN and XBiotech, and Almirall, all outside the present study. Dr Naik has received grant support from Abbvie and consulting fees from 23andme, all outside the present study. Dr Naik and Dr Lowes are Hidradenitis Suppurativa Foundation (HSF) board members.

References

1.

Alavi A, Anooshirvani N, Kim WB, Coutts P, Sibbald RG. Quality-of-life impairment in patients with hidradenitis suppurativa: a Canadian study. Am J Clin Dermatol. 2015;16(1):61-65. doi:10.1007/s40257-014-0105-5PubMedGoogle ScholarCrossref

Garg A, Kirby JS, Lavian J, Lin G, Strunk A. Sex- and age-adjusted population analysis of prevalence estimates for hidradenitis suppurativa in the United States. JAMA Dermatol. 2017;153(8):760-764. doi:10.1001/jamadermatol.2017.0201

ArticlePubMedGoogle ScholarCrossref

Ingram JR, Jenkins-Jones S, Knipe DW, Morgan CLI, Cannings-John R, Piguet V. Population-based Clinical Practice Research Datalink study using algorithm modelling to identify the true burden of hidradenitis suppurativa. Br J Dermatol. 2018;178(4):917-924. doi:10.1111/bjd.16101PubMedGoogle ScholarCrossref

Lewis V, Finlay AY. 10 years experience of the Dermatology Life Quality Index (DLQI). J Investig Dermatol Symp Proc. 2004;9(2):169-180. doi:10.1111/j.1087-0024.2004.09113.xPubMedGoogle ScholarCrossref

Tamási B, Brodszky V, Péntek M, et al. Validity of the EQ-5D in patients with pemphigus vulgaris and pemphigus foliaceus. Br J Dermatol. 2019;180(4):802-809. doi:10.1111/bjd.16883PubMedGoogle ScholarCrossref

Karimkhani C, Boyers LN, Margolis DJ, et al. Comparing cutaneous research funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with 2010 Global Burden of Disease results. PLoS One. 2014;9(7):e102122. doi:10.1371/journal.pone.0102122PubMedGoogle ScholarCrossref

Chen W-T, Chi C-C. Association of hidradenitis suppurativa with inflammatory bowel disease: a systematic review and meta-analysis [published online July 10, 2019]. JAMA Dermatol. doi:10.1001/jamadermatol.2019.0891

ArticleGoogle Scholar

Reddy S, Strunk A, Garg A. Comparative overall comorbidity burden among patients with hidradenitis suppurativa [published online April 17, 2019]. JAMA Dermatol. doi:10.1001/jamadermatol.2019.0164

ArticleGoogle Scholar

Machado MO, Stergiopoulos V, Maes M, et al. Depression and anxiety in adults with hidradenitis suppurativa: a systematic review and meta-analysis [published online June 5, 2019]. JAMA Dermatol. doi:10.1001/jamadermatol.2019.0759

ArticleGoogle Scholar

Thorlacius L, Cohen AD, Gislason GH, Jemec GBE, Egeberg A. Increased suicide risk in patients with hidradenitis suppurativa. J Invest Dermatol. 2018;138(1):52-57. doi:10.1016/j.jid.2017.09.008PubMedGoogle ScholarCrossref

Alikhan A, Sayed C, Alavi A, et al. North American clinical management guidelines for hidradenitis suppurativa: A publication from the United States and Canadian Hidradenitis Suppurativa Foundations: Part I: Diagnosis, evaluation, and the use of complementary and procedural management [published online March 11, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.02.067Google Scholar

Alikhan A, Sayed C, Alavi A, et al. North American clinical management guidelines for hidradenitis suppurativa: a publication from the United States and Canadian Hidradenitis Suppurativa Foundations: Part II: Topical, intralesional, and systemic medical management [published online March 11, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.02.067Google Scholar

https://jamanetwork.com/journals/jamadermatology/fullarticle/2737811

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Synopsis:

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Background

Hidradenitis suppurativa (HS) is a chronic inflammatory disorder that primarily affects women of childbearing age. There is a paucity of data on HS disease activity during menstruation, pregnancy, and menopause and the potential impact of HS on the method of delivery.

Objective

We aimed to characterize the natural history of HS symptoms during menses, pregnancy, and menopause. We also sought to evaluate the potential impact of HS on delivery method and whether there were delivery-related healing complications unique to women with HS.

Methods

An anonymous survey was distributed via social media to international HS support groups and patients at three HS specialty clinics in North America. Responses were collected from March to July 2019.

Results

A total of 279 respondents answered questions on disease changes during pregnancy. Menstruation caused worsening of HS symptoms in 76.7%, no change in 22.2%, and improvement in 1.1%. During pregnancy, the distribution between symptoms worsening (34.8%), having no change (28.7%), and improving (36.6%) was relatively even. After menopause, participants typically reported either worsening (39.5%) or no change (44.2%) in HS symptoms. Among respondents with anogenital HS involvement who delivered vaginally, 3.1% believed that HS interfered with vaginal delivery (VD), and 23.5% believed that VD caused an HS flare. Cesarean section (C-section) delivery was reported by 44.2% of participants. Ten participants reported that they were advised by their doctor to have a C-section instead of a VD because of severe anogenital HS. Of those who underwent a C-section, 33.9% reported that HS interfered with incision healing, and 51.2% reported developing new HS lesions in their C-section scar.

Conclusion

To our knowledge, this is the first study describing the potential influence of HS on a patient’s method of delivery. Multidisciplinary collaboration plays a pivotal role in developing individualized treatment and birth plans for pregnant women with HS

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Full Research:

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https://www.sciencedirect.com/science/article/pii/S2352647520301143

Scarred for Life: 2020 – A National Report of Patients’ Experiences

Living with Hidradenitis Suppurativa

https://canadianskin.ca/advocacy/hs-report

Background: Increased interest in hidradenitis suppurativa (HS) research is encouraging. A critical analysis of the state of HS literature may demonstrate the strength of existing knowledge and highlight current gaps.

Objectives: To analyse changes in HS literature from 2008 to 2018 with focus on quantity and quality of annual publications.

Methods: Review of all indexed publications reporting on HS on PubMed. Publications were categorized based on study design, study topic and treatment type where applicable. Publications were dichotomized into high level of evidence and low level of evidence groups. Linear regression analyses were performed to investigate the change in publication number over time. Annual average growth rate and distribution of high versus low level of evidence publications were calculated.

Results: Publication number increased over time overall (R2 = 0.64, P = 0.003) and for all publication types except randomized clinical trials. Case reports and case series represented the majority of HS publications (n = 479, 40.3%). Treatment was the main focus of publications (n = 445, 37.6%) with increasing interest in medical management evident in recent years. Distribution of low level of evidence studies (n = 974) compared with high level of evidence studies over time (n = 209) was significant (x2 : 11.45, P = 0.0007). High level of evidence studies had a higher average annual growth rate (49.9%) compared with low level of evidence studies (23.7%). Few randomized clinical trials were performed (n = 16), focusing equally on medical or procedural treatments.

Conclusions: Hidradenitis suppurativa research is undergoing a tremendous shift, suggesting rapid maturation of the field. Current HS literature, however, remains primarily based on limited clinical observation data, with a particular lack of randomized clinical trials. Despite this, the increase in high level of evidence studies is encouraging and may herald a shift towards improved disease understanding and treatment paradigms.

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https://www.ncbi.nlm.nih.gov/m/pubmed/31968146/?i=15&from=hidradenitis%20suppurativa

Creation of a Registry to Address Knowledge Gaps in

Hidradenitis Suppurativa and Pregnancy

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Research correspondence article:

https://jamanetwork.com/journals/jamadermatology/fullarticle/2758413

Research correspondence reply to article:

https://jamanetwork.com/journals/jamadermatology/fullarticle/2758414

Should HS/acne inversa best be renamed as “dissecting terminal hair folliculitis”?

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Hidradenitis suppurativa/acne inversa is a diverse, enigmatic and distressful disease that has aroused growing interest in specialists from different disciplines. Both names describe its classical manifestations in the intertriginous regions and reflect the historical view of the disease definition, but cause confusions in the understanding of its pathogenesis and classification. In the light of the advance in clinical, histopathological and pathophysiological findings, we propose the term “dissecting terminal hair folliculitis” (DTHF) to characterize its disease nature as folliculitis instead of acneiform disease or apocrine gland disorder. DTHF attacks exclusively the terminal hair follicles in an overwhelming majority of adults, initiating from the fragile acroinfundibulum leading to a non‐infectious overreaction of innate immunity system with inflammation that may fiercely dissect and engulf all the surrounding tissues accompanied by secondary bacterial infections. Evidence indicates that perifolliculitis capitis abscedens et suffodiens and pilonidal disease are very likely regional variants of DTHF with the same pathogenesis. Treatment of DTHF remains frustrating. The benefit of biologics in targeting inflammation is so far non‐specific, palliative and inconsistent. Hair epilation and photodynamic therapy in treatment of the disease is questionable in consideration of the pathogenesis. Genetic and dtranslational research, especially on the Notch signalling pathways, will yield breakthrough in the development of novel treatment modalities.

1 Introduction: Times of Confusion

First described in 1839 by Velpeau in a patient with abscesses in the axillary, mammary and perianal regions (s1), association between HS/AI and sweat glands was noted by Verneuil in 1854 (s2). The term hidradenitis destruens suppurativa was first proposed by Pollitzer in 1894 (s3). Kierland reported the concurrence of acne conglobata (AC), HS and perifolliculitis capitis abscedens et suffodiens in 1951 (s4), which was later coined as follicular occlusion triad by Pillsbury, Shelley and Kligman (s5). In 1989, Plewig and Steger suggested to use AI to cover the whole spectrum of acne tetrad, namely AC, HS/AI, perifolliculitis capitis abscedens et suffodiens and pilonidal disease (s6). In 2006, an international group of experts presented the first monograph on HS/AI (s7). In 2010, gene mutations encoding essential components of the γ‐secretase multiprotein complex were identified in Chinese patients with the autosomal dominant familial form of HS/AI.1 In spite of the advance in the understanding of its pathogenesis and publication of many national or international guidelines for disease classification and management (s8,s9), the aetiology of this group of diseases remains incompletely understood, and no standard treatment has been established. Through a critical re‐evaluation of the taxonomical changes and a better stratification of the clinical manifestations, this work is aimed to clarify the confusion in disease categorization, explain the difference in therapeutic response and shed light on new research pathways.

2 Anatomy, Physiology and Pathology

Three kinds of human hair follicles are recognized: sebaceous, vellus and terminal, which differ significantly in their fine structure and distribution.2 Acne occurs in sebaceous follicles and never in terminal hair follicles. Sebaceous follicles are widely distributed over the entire skin except on the palms and soles. The apocrine sweat glands are mainly found in axillae, pubis, labia majora, scrotum, perineum, perianal regions and areola of the breast, but lacking in other intertriginous regions like submammary, antecubital or popliteal. Unlike eccrine sweat glands, apocrine sweat glands are innervated by the adrenergic nerve fibres, and their long excretory ducts open into the acroinfundibulum of the terminal hair follicles (Fig. S1A).

The earliest pathologic change of HS/AI was observed in the junction between apocrine sweat duct and terminal hair infundibulum, with two major findings (Fig. S1B): (i) microcomedones in the ampulla of the apocrine sweat duct draining into the hair acroinfundibulum;2 (ii) mild hyperplasia and segmental spongiosis of the epithelium in the acroinfundibulum (Fig. S1C,D), which is speculated to be caused by the epithelial instability associated with impaired Notch‐MKP‐1 signalling.3 It is unclear whether they happen concurrently or which event comes first. The subsequent breakage of the infrainfundibulum with rupture of the follicular epithelium initiates the inflammatory cascade (Fig. S2A), sometimes with violent and stormy progression to cause a tsunami‐like damage, whereby the apocrine and eccrine sweat glands are passively engulfed by the flooding inflammation rampaging everywhere (Fig. S2C–E). At this stage, the sebaceous follicles and sebaceous glands of terminal hair follicles are affected as innocent bystanders. This observation has been shared and supported by many subsequent studies, showing that the terminal hair infundibulum is the primary site of defect.4-6 Mechanical stress can act as a possible trigger in the disease development (s10,s11).

It is unclear whether the reduced number and volume of sebaceous glands in uninvolved hair follicles from patients with HS/AI is in a causal link or is the result of a common pathogenic process (s12). This is observed in the lesions of HS/AI, but does not apply to the uninvolved terminal hair follicles in the unaffected regions of these patients. All terminal hair follicles have more or less attached sebaceous lobules, smaller or bigger in size, which can modulate during the hair cycle.2 In both human and animals, it is known that with irritation, including inflammation, the sebaceous glands regress in size or virtually disappear temporarily.

3 Hidradenitis Suppurativa (HS), Acne Inversa (AI) and Dissecting Terminal Hair Folliculitis (DTHF): Three Names for the Same Disease

Based on the above discussion, one of the authors (GP) first proposed the term dissecting terminal folliculitis in 2009 (s13), now more precisely termed as dissecting terminal hair folliculitis (DTHF), to replace HS and AI. These three synonyms can be redefined as follows:

We suggest to abandon the term HS, which is incorrect in terms of pathogenesis and misleading for the patients. Infectious or non‐infectious aetiology should be specifically designated in the inflammation of eccrine or apocrine sweat glands associated with suppurative changes. Due to the expression of innate defense antimicrobial peptides in both eccrine and apocrine sweat glands (s14, s15), infectious eccrine hidradenitis is a rare presentation (s16), while infectious apocrine hidradenitis has not yet been confirmed. The single case reports about a complete remission of the disease caused by rare pathogens suggest the possible existence of an infectious apocrine hidradenitis which can mimic DTHF clinically (s17).

The nomenclature of AI and acne tetrad was based on their common pathogenesis of abnormal keratinization in the follicular infundibulum. However, acne is a disease sui generis with a wide spectrum of clinical manifestations occurring exclusively in sebaceous follicles. DTHF is also a unique disease of its own originating from terminal hair follicles, with the attached sebaceous glands being secondarily involved. Although rare, AC can be observed in the intertriginous regions and should be distinguished from DTHF. Vice versa, DTHF can occur on the sebaceous gland‐rich, acne‐prone regions like beard and chest and can be confused with AC.

As a distinct entity beginning from the acroinfundibulum of terminal hair follicles, dissecting process in DTHF can be understood in two aspects: (i) clinically the involved regions are cut through with undermining and communicating draining sinuses and fistulae, leading to extensive interwoven scars; (ii) histologically the fragile hyperproliferative follicular acroinfundibulum becomes dissected and the subsequent fierce inflammation makes its way through various directions of the dermis destroying all anatomic structures (Fig. S2A,B).2 Apocrine sweat glands or sebaceous glands are secondarily attacked. DTHF can be further labelled as axillary, submammary, inguinal, gluteal or facial DTHF, according to the site of involvement.

4 Clinical Impact of the Redefinitions

Synchrony and metachrony between AC and DTHF: Acne and its massive expression AC usually begin from teenage and most of the patients never develop DTHF later in life. On the other hand, DTHF is a disease of adults and very rare in children, runs relentlessly, often ad infinitum, with most of the patients never experiencing severe acne or AC in early life (Table ST1). AC and DTHF do not develop in parallel (no synchrony), but it may start in certain patients initially with AC accompanying puberty, and being attacked by DTHF later (metachrony). The statistics about natural intersection or concurrence of both diseases is unknown. In our own experience, it is uncommon. Differentiation between DTHF and AC in the regions abundant with both terminal hair and sebaceous follicles can be challenging, such as chest, back and beard. A careful histological examination in the early stage can help.

As compared to AC, the non‐hereditary, non‐syndromic DTHF affects mainly Caucasian women (female to male ration 3‐4 to 1) with a close association with smoking and obesity (s18–s20). The seemingly low prevalence of DTHF in China,7 Japan (s21), Korea and Taiwan might be explained by a generally lower prevalence of hirsutism, obesity, smoking and the use of contraceptives in women from these regions. Moreover, more men are affected than women in these regions, based on the case series reported to date (s22).7

DTHF can occur in prepubertal age, estimated to account for 1% or lower of all affected patients (s23, s24). Most of the reported cases have certain endocrine or hormonal abnormalities, while girls already show visible terminal hair growth in the pubic or axillary areas (s25). Successful treatment with oral finasteride lends support to our observation (s26).

DTHF and AC mostly occur in an isolated non‐hereditary, non‐syndromic pattern. The pyogenic arthritis–pyoderma gangrenosum–acne (PAPA) syndrome is an autosomal dominant disease entity with well‐defined genetic mutations and usually showing severe nodular/conglobate acne . Observations demonstrate significant overlapping between acne fulminans and the synovitis–acne–pustulosis–hyperostosis–osteitis (SAPHO) syndrome. In less clear syndromes like the pyoderma gangrenosum–acne–suppurative hidradenitis (PASH) syndrome and pyogenic arthritis–pyoderma gangrenosum–acne–suppurative hidradenitis (PAPASH) syndrome, acne manifests to a variable degree and severe acne occurs much more uncommonly (s27–s29). Cases showing nodulocystic lesions in the beard and chest should be differentiated from DTHF in histology. As acne is a very common disease, it raises the question whether acne is an essential component of these syndromes.

DTHF and AC respond very differently to treatment. Oral isotretinoin has been demonstrated to be an effective treatment for AC but not for DTHF (s30, s31). The efficacy of TNF‐α inhibitors or interleukin (IL)‐1β blockers on DTHF, especially the non‐syndromic type, has so far been inconsistently demonstrated (s32–s35).8 Given the rarity of controlled studies, biologics seem to benefit more the arthritis and pyoderma gangrenosum in diverse associated rare syndromes, their effect on acne is muss less convincing and long‐term efficacy remains to be confirmed (s36, s37).

Laser hair epilation has been proposed to be a promising treatment for DTHF, so far with scanty evidence (s38). In theory, therapy should aim to normalize or stabilize the follicular infundibulum but not to inhibit hair growth. Further understanding on the possible working mechanisms of laser treatment is required.

Perifolliculitis capitis abscedens et suffodiens (Hoffmann disease) and pilonidal disease both share many clinical, histological and immunohistological characteristics with DTHF (s39).9 Many similarities also exist in their treatment options and disease course. They are definitely the disease of terminal hair follicles in the category of “folliculitis” and no longer belong to acne based on the redefinition.

5 Conclusion

Terminal hair follicles and sebaceous follicles are two different hair follicles of distinctive natures. In pathophysiology, DTHF is neither hidradenitis nor acne; instead, it is folliculitis of terminal hair follicles. Inconsistency in the description of DTHF reflects multifacetedness of the disease. The terms Velpeau or Verneuil disease, HS, AI and many others will remain of historical interest but can be replaced with DTHF in the future in favour of medical advances. Instability of acroinfundibular epithelium is very likely the aetiology, whereby mechanical stress can trigger the disease initiation. A pivotal role of Notch signalling and innate immunity has been demonstrated in pathogenesis, while antimicrobial or anti‐inflammatory treatment cannot cure the disease. The use of acne triad or acne tetrad is misleading while follicular occlusion triad is less accurate and differentiating because occlusion is not the primary event observed. The proposal of DTHF will pave and lead the way for a better understanding of pathogenesis and future design of novel treatment modalities.

Acknowledgements

Figures S1A,B and S2B–D have been published in Plewig G, Kligman AM. Acne and Rosacea. Springer, Heidelberg 2000. Copyright of all illustrations Gerd Plewig, Munich.

Both authors have fulfilled the requested criteria for ethical guidelines. Both authors performed the research, analysed the data, drafted and wrote the paper and revised it critically and approved the submitted and final versions.

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https://doi.org/10.1111/exd.13211

https://onlinelibrary.wiley.com/doi/full/10.1111/exd.13211

Hidradenitis Suppurativa in Sweden:

A Registry-Based Cross-Sectional Study of 13,538 Patients

Synopsis:

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Background: Hidradenitis suppurativa (HS) is a chronic, inflammatory skin condition with nodules and fistula formation and scarring. It is a debilitating disease with a severe negative impact on quality of life. There is a need for increased knowledge about the social and lifestyle characteristics of patients with HS in general, and pregnant women in particular.

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Objectives: The aims of this study were to investigate and describe social characteristics and comorbidity in all HS patients in Sweden as well as to study the prevalence of lifestyle factors associated with negative impact on health and pregnancy in Swedish pregnant women with HS.

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Methods: A registry-based cross-sectional study was performed by record linkage between Swedish registers covering the entire population. A cohort of 13,538 HS patients diagnosed with HS in specialised care during the years 2001-2014 and a subgroup of 1,368 HS patients who had undergone pregnancy during 2010-2015 were defined and described. Aggregated public data on the entire Swedish population and all pregnancies in 2014 were described for reference.

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Results: The HS population had an average age of 44 years on December 31, 2014. The prevalence of HS was 0.14%. In comparison to the Swedish reference population the HS patients were more often women, unmarried (36 vs. 44% married), and had lower education (68 vs. 82% with an upper-secondary school degree or higher) and lower income (39 vs. 16% made SEK <100,000 a year). Comorbidity was 3% for inflammatory bowel disease and 8% for type 2 diabetes. The subgroup analysis showed high prevalence of overweight, obesity, and smoking in pregnant women with HS.

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Conclusions: The results from this comprehensive characterisation of Swedish HS patients may be used to improve preventive measures, information, and care for this vulnerable group.

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Full Research Link: https://www.ncbi.nlm.nih.gov/m/pubmed/32015234/?