Hidradenitis suppurativa – prevalence analyses of German statutory health insurance data

Diagnoseverzögerung bei Hidradenitis suppurativa untersucht mit Daten von sozialen Medien und gesetzlichen Krankenversicherungen

Hintergrund

Die chronisch‐entzündliche Hauterkrankung Hidradenitis suppurativa (HS) führt bei Betroffenen zu ausgeprägten Schmerzen und verminderter Lebensqualität. Trotzdem vergehen oft mehrere Jahre bis zur korrekten Diagnosestellung. In dieser Analyse sollten krankheitsbedingte Erfahrungen und Wege der Patienten mit HS untersucht und der ärztlichen Sicht gegenübergestellt werden.

Patienten und Methodik

Für die Studie wurden Ergebnisse einer Befragung von Dermatologen und deren Patienten zur Versorgungsrealität bei HS in Deutschland sowie öffentliche Beiträge auf Internet‐Foren und in sozialen Medien analysiert. Zusätzlich wurden Abrechnungsdaten deutscher Krankenkassen ausgewertet.

Ergebnisse

Patienten mit HS haben eine um 43,3% reduzierte Arbeitsfähigkeit. Die Dermatologie (26,5%) war der am häufigsten konsultierte Fachbereich, die Diagnose HS wurde dabei überwiegend im stationären Bereich (43,8%) gestellt. Als häufigste alternative Diagnose bei HS‐Patienten wurden Abszesse angegeben (53,2%). Die Analyse von Wechseln zu anderen Behandlern ergab, dass diese in der Dermatologie (34,1%) und der Chirurgie (42,4%) vorwiegend innerhalb des Fachbereiches erfolgen. Überweisungen erhielt die Dermatologie mehrheitlich aus dem hausärztlichen Bereich (67,1%) allerdings nur 12,1% von Chirurgen.

Schlussfolgerungen

Die Diagnoseverzögerung und die dadurch verlängerte Krankheitsbelastung von Patienten mit HS muss dringend reduziert werden. Dazu sollte, möglichst schon als Teil des Medizinstudiums, ein über die Dermatologie hinaus reichendes Bewusstsein für die Erkrankung, ihre Erkennung und Behandlung gefördert werden.

S2k‐Leitlinie zur Therapie der Hidradenitis suppurativa/Acne inversa – Kurzfassung

Die S2k‐Leitlinie der Hidradenitis suppurativa/Acne inversa (HS/AI) soll eine akzeptierte Entscheidungshilfe für die Auswahl/Durchführung einer geeigneten/suffizienten Therapie liefern. Hidradenitis suppurativa/Acne inversa ist eine chronisch‐rezidivierende, entzündliche, potenziell mutilierende Hauterkrankung des terminalen Haartalgdrüsenapparats, mit schmerzhaften, entzündlichen Läsionen in den apokrinen drüsenreichen Körperregionen. Ihre Punktprävalenz in Deutschland ist 0,3%, sie wird mit einer Verspätung von 10,0 ± 9,6 Jahren diagnostiziert. Abnormale Differenzierung der Keratinozyten des Haartalgdrüsenapparats und eine begleitende Entzündung bilden die zentrale pathogenetische Grundlage. Primäre HS/AI‐Läsionen sind entzündliche Knoten, Abszesse und drainierende Tunnel. Rezidive in den letzten 6 Monaten mit mindestens zwei Läsionen an den Prädilektionsstellen verweisen auf eine HS/AI mit einer 97‐prozentigen Genauigkeit. HS/AI‐Patienten leiden an einer deutlichen Einschränkung der Lebensqualität. Zur korrekten Therapieentscheidung sollen Klassifikation und Aktivitätsbewertung mit einem validierten Instrument erfolgen, wie dem International Hidradenitis Suppurativa Severity Scoring System (IHS4). Hidradenitis suppurativa/Acne inversa wird nach der Ausprägung der nachweisbaren Entzündung in zwei Formen eingeteilt: aktive, entzündliche (milde, mittelschwere und schwere nach IHS4) und vorwiegend inaktive, nicht entzündliche (Hurley‐Grad‐I, ‐II und ‐III) HS/AI. Orale Tetrazykline oder eine 5‐tägige intravenöse Therapie mit Clindamycin sind mit der Effektivität von Clindamycin/Rifampicin vergleichbar. Subkutan applizierbares Adalimumab, Secukinumab und Bimekizumab sind für die Therapie der HS/AI zugelassen. Für die vorwiegend nicht entzündliche Erkrankungsform stehen verschiedene operative Verfahren zur Verfügung. Medikamentöse/chirurgische Kombinationen gelten als ganzheitliches Therapieverfahren.

Diagnostic delay in Hidradenitis suppurativa investigated using data from social media and from statutory health insurances

BACKGROUND

The chronic inflammatory skin disease hidradenitis suppurativa (HS) leads to severe pain and reduced quality of life. Nonetheless, it often takes years until a correct diagnosis is made. In this analysis, disease-related experiences and pathways of patients with HS were investigated and compared with the physicians' perspective.

METHODS

Public posts on forums and social media as well as results of a survey conducted among dermatologists and their patients on the actual medical care reality of HS in Germany were analysed. Furthermore, claims data from German health insurance companies were evaluated.

RESULTS

Patients with HS suffer from a 43.3% reduction in working ability. Dermatology (26.5%) was the most frequently consulted specialty, with HS diagnosed predominantly in the inpatient setting (43.8%). Abscesses were described as the most frequent alternative diagnosis in HS patients (53.2%). Patient-reported changes of physicians in dermatology (34.1%) and surgery (42.4%) occurred predominantly within the specialty. Dermatology received most referrals from general practitioners (67.1%), but only 12.1% from surgeons.

CONCLUSION

There is an urgent need to reduce the delay in diagnosis and the prolonged burden of disease in patients with HS. Therefore, awareness of the disease, its detection and treatment which goes beyond dermatology should be promoted, if possible as part of medical studies.

S2k guideline for the treatment of hidradenitis suppurativa / acne inversa - Short version

The S2k guideline on hidradenitis suppurativa/acne inversa (HS/AI) aims to provide an accepted decision aid for the selection/implementation of appropriate/sufficient therapy. HS/AI is a chronic recurrent, inflammatory, potentially mutilating skin disease of the terminal hair follicle-glandular apparatus, with painful, inflammatory lesions in the apocrine gland-rich regions of the body. Its point prevalence in Germany is 0.3%, it is diagnosed with a delay of 10.0 ± 9.6 years. Abnormal differentiation of the keratinocytes of the hair follicle-gland apparatus and accompanying inflammation form the central pathogenetic basis. Primary HS/AI lesions are inflammatory nodules, abscesses and draining tunnels. Recurrences in the last 6 months with at least 2 lesions at the predilection sites point to HS/AI with a 97% accuracy. HS/AI patients suffer from a significant reduction in quality of life. For correct treatment decisions, classification and activity assessment should be done with a validated tool, such as the International Hidradenitis Suppurativa Severity Scoring System (IHS4). HS/AI is classified into two forms according to the degree of detectable inflammation: active, inflammatory (mild, moderate, and severe according to IHS4) and predominantly inactive, non-inflammatory (Hurley grade I, II and III) HS/AI. Oral tetracyclines or 5-day intravenous therapy with clindamycin are equal to the effectiveness of clindamycin/rifampicin. Subcutaneously administered adalimumab, secukinumab and bimekizumab are approved for the therapy of HS/AI. Various surgical procedures are available for the predominantly non-inflammatory disease form. Drug/surgical combinations are considered a holistic therapy method.

Biology of Interleukin-17 and Novel Therapies for Hidradenitis Suppurativa

Skin disorders affect ∼40% of the human population. One of the most debilitating cutaneous disorders is Hidradenitis suppurativa (HS), a noncommunicable chronic inflammatory disease with an estimated global prevalence of 0.4% to 2.5%. In January 2011, high levels of IL-17 were discovered in skin lesions of HS patients. In the following years, translational and clinical research led to a better understanding of the pathogenesis of HS. In June 2023, more than 12 years after the initial note, secukinumab, an anti-IL-17A monoclonal antibody, was approved for the treatment of moderate to severe HS. This is the next milestone in improving the treatment of these patients after the approval of the anti-TNF-α monoclonal antibody adalimumab in 2015. In this review article, we present the IL-17 pathway in HS and discuss the use of secukinumab as a therapeutic option for this disease. Our review starts with a description of the epidemiology, clinical features, etiology, and pathogenesis of HS. An overview of the IL-17/IL-17 receptor system in general and a detailed description of the known facts about the expression and action of IL-17 in HS follow. Afterward, we consider the results of clinical trials evaluating the safety and efficacy of IL-17 inhibitors in HS. Finally, a comparison is made between secukinumab and adalimumab and the characteristics of the patients that may be particularly suitable for each of these biologics are described.

Molecular and functional changes in neutrophilic granulocytes induced by nicotine: a systematic review and critical evaluation

Background

Over 1.1 billion people smoke worldwide. The alkaloid nicotine is a prominent and addictive component of tobacco. In addition to tumors and cardiovascular disorders, tobacco consumption is associated with a variety of chronic-inflammatory diseases. Although neutrophilic granulocytes (neutrophils) play a role in the pathogenesis of many of these diseases, the impact of nicotine on neutrophils has not been systematically reviewed so far.

Objectives

The aim of this systematic review was to evaluate the direct influence of nicotine on human neutrophil functions, specifically on cell death/damage, apoptosis, chemotaxis, general motility, adhesion molecule expression, eicosanoid synthesis, cytokine/chemokine expression, formation of neutrophil extracellular traps (NETs), phagocytosis, generation of reactive oxygen species (ROS), net antimicrobial activity, and enzyme release.

Material and methods

This review was conducted according to the PRISMA guidelines. A literature search was performed in the databases NCBI Pubmed® and Web of Science™ in February 2023. Inclusion criteria comprised English written research articles, showing in vitro studies on the direct impact of nicotine on specified human neutrophil functions.

Results

Of the 532 originally identified articles, data from 34 articles were finally compiled after several evaluation steps. The considered studies highly varied in methodological aspects. While at high concentrations (>3 mmol/l) nicotine started to be cytotoxic to neutrophils, concentrations typically achieved in blood of smokers (in the nmol/l range) applied for long exposure times (24-72h) supported the survival of neutrophils. Smoking-relevant nicotine concentrations also increased the chemotaxis of neutrophils towards several chemoattractants, elevated their production of elastase, lipocalin-2, CXCL8, leukotriene B4 and prostaglandin E2, and reduced their integrin expression. Moreover, while nicotine impaired the neutrophil phagocytotic and anti-microbial activity, a range of studies demonstrated increased NET formation. However, conflicting effects were found on ROS generation, selectin expression and release of β-glucuronidase and myeloperoxidase.

Conclusion

Nicotine seems to support the presence in the tissue and the inflammatory and selected tissue-damaging activity of neutrophils and reduces their antimicrobial functions, suggesting a direct contribution of nicotine to the pathogenesis of chronic-inflammatory diseases via influencing the neutrophil biology.

Epidemiology of hidradenitis suppurativa

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

Neutrophilic granulocyte-derived B-cell activating factor supports B cells in skin lesions in hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by painful inflamed nodules, abscesses, and pus-draining tunnels appearing in axillary, inguinal, and perianal skin areas. HS lesions contain various types of immigrated immune cells.

OBJECTIVE

This study aimed to characterize mediators that support lesional B/plasma cell persistence in HS.

METHODS

Skin samples from several cohorts of HS patients and control cohorts were assessed by mRNA sequencing, quantitative PCR on reverse-transcribed RNA, flow cytometry, and immunohistofluorescence. Blood plasma and cultured skin biopsy samples, keratinocytes, dermal fibroblasts, neutrophilic granulocytes (neutrophils), monocytes, and B cells were analyzed. Complex systems biology approaches were used to evaluate bulk and single-cell RNA sequencing data.

RESULTS

Proportions of B/plasma cells, neutrophils, CD8+ T cells, and M0 and M1 macrophages were elevated in HS lesions compared to skin of healthy and perilesional intertriginous areas. There was an association between B/plasma cells, neutrophils, and B-cell activating factor (BAFF, aka TNFSF13B). BAFF was abundant in HS lesions, particularly in nodules and abscesses. Among the cell types present in HS lesions, myeloid cells were the main BAFF producers. Mechanistically, granulocyte colony-stimulating factor in the presence of bacterial products was the major stimulus for neutrophils' BAFF secretion. Lesional upregulation of BAFF receptors was attributed to B cells (TNFRSF13C/BAFFR and TNFRSF13B/TACI) and plasma cells (TNFRSF17/BCMA). Characterization of the lesional BAFF pathway revealed molecules involved in migration/adhesion (eg, CXCR4, CD37, CD53, SELL), proliferation/survival (eg, BST2), activation (eg, KLF2, PRKCB), and reactive oxygen species production (eg, NCF1, CYBC1) of B/plasma cells.

CONCLUSION

Neutrophil-derived BAFF supports B/plasma cell persistence and function in HS lesions.

The impact of surgical interventions on the psychosocial well-being of patients with hidradenitis suppurativa

BACKGROUND AND OBJECTIVES

Hidradenitis suppurativa is a chronic inflammatory skin disease. Depending on disease severity, a combination of conservative and surgical treatments is necessary. This analysis aimed to determine the impact of surgical interventions on patient psychosocial well-being.

PATIENTS AND METHODS

This is a prospective, noninterventional, multicenter study. The medical history, medical examination, and patient-reported outcomes, including the Hospital Anxiety and Depression Scale, Dermatology Life Quality Index, and the Short Form-12 Health Survey, were collected from 481 patients with hidradenitis suppurativa.

RESULTS

Among all patients with hidradenitis suppurativa included in this study, 74.2% reported surgery before study inclusion, of whom 92.4% could identify surgery type and location. Although adjusted for confounding factors, such as disease severity and activity, the aforementioned patient reported outcomes, did not vary significantly between groups of patients with different techniques and number of prior surgical intervention. However, patients without any prior surgical intervention yielded significantly better scores.

CONCLUSIONS

In patients with hidradenitis suppurativa, previous surgery was associated with worse outcomes in anxiety, depression, and quality of life, showing the apparent need of psychological support. It remains unclear whether the morbidity of surgical procedures or a possible higher severity score in patients undergoing surgery is responsible.

The impact of hidradenitis suppurativa on professional life

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that affects intertriginous skin.

OBJECTIVES

To determine the extent of work ability and productivity impairment as a result of HS in Germany.

METHODS

A prospective, multicentre, epidemiological, noninterventional study of patients with HS was conducted. Medical history, medical examination performed by dermatologists and patient-reported outcomes [Work Ability Index (WAI) and Work Productivity and Activity Impairment (WPAI)] were collected.

RESULTS

Of the 481 patients with HS included in the study, 99% were below the current statutory retirement age. In total, 53·3% of patients were working full time, 16·8% part time and 7·3% had retired. The unemployment rate was 12·6%, two times higher than in the general German population. Medical leave because of HS, within the last 6 months, was reported in 41·4% [95% confidence interval (CI) 36·9-46·0], with a duration of 39·3 days on average (95% CI 32·4-46·1). The mean HS-related WPAI absenteeism was 13.3% (95% CI 9·7-16·8), and the loss in productivity because of HS during working hours (WPAI presenteeism) was 25.2% (95% CI 21·8-28·6). Presenteeism was associated with HS disease severity. Overall work impairment because of HS was 33·4% (95% CI 29·3-37·6). The WAI score for patients was 32·2, ∼20% lower than for the average German employee. Only 62·8% of patients were relatively certain that they would be able to perform their work in the coming 2 years. Being more depressed and having more severe pain were associated with lower work ability and overall work impairment. The estimated annual loss of gross value added because of HS for Germany was ∼€12.6 billion (€3.3 billion related to a lower employment rate, €3.5 billion related to absenteeism and €5.8 billion related to presenteeism).

CONCLUSIONS

HS leads to a substantial decrease in work ability and productivity and considerable loss of gross value added. Impairment during working hours correlates with disease severity, underlining the socioeconomic importance of early and adequate treatment. Furthermore, decreased work ability and productivity is linked to depressed mood and severe pain, aspects that need more attention in patient care.

Sex-disaggregated population analysis in patients with hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a common chronic inflammatory skin disease, which affects both sexes.

OBJECTIVES

Identification of sex-specific risk factors, comorbidity, clinical manifestations, and treatments in HS patients.

METHODS

A non-interventional, cross-sectional, mono-centric study with 500 HS patients. All patients were examined by dermatologists. Prospectively collected demographic, anamnestic, clinical data, and blood parameters were evaluated.

RESULTS

There were no significant differences in age at HS onset and in disease duration between female and male patients. Furthermore, no differences regarding the family history for HS were found between sexes. Regarding further risk factors for HS, central obesity was more frequent in women while extensive cigarette smoking and acne vulgaris were more commonly found among male patients. Regarding comorbidity, lower HDL-levels were significantly more frequent in men. Female patients were found to suffer significantly more often from back pain, especially in the neck/shoulder region and lower back. Analyzing the clinical manifestation of HS, the groin was more frequently involved in women and the axillae in men. Women showed a higher number of skin sites with inflammatory nodules, whereas fistulas were observed more frequently in men. Nevertheless, there was no difference in HS treatment applied to female vs. male patients.

LIMITATIONS

Data were obtained from a mono-centric study.

CONCLUSION

Significant differences in HS risk factors, comorbidity, and clinical manifestation exist between female and male patients. Thus, sex-specific differences should be taken into account in the prevention as well as medical and surgical treatment of HS patients.

Phytotherapeuthics Affecting the IL-1/IL-17/G-CSF Axis: A Complementary Treatment Option for Hidradenitis Suppurativa?

Hidradenitis suppurativa (HS; also designated as acne inversa) is a chronic inflammatory disease characterized by painful skin lesions that occur in the axillary, inguinal, gluteal and perianal areas of the body. These lesions contain recurring deep-seated, inflamed nodules and pus-discharging abscesses and fistulas. Affecting about 1% of the population, this common disease has gained appropriate clinical attention in the last years. Associated with numerous comorbidities including metabolic syndrome, HS is considered a systemic disease that severely impairs the quality of life and shortens life expectancy. Therapeutic options for HS are limited, comprising long-term antibiotic treatment, the surgical removal of affected skin areas, and neutralization of TNF-α, the only approved systemic treatment. Novel treatment options are needed to close the therapeutic gap. HS pathogenesis is increasingly better understood. In fact, neutrophilic granulocytes (neutrophils) seem to be decisive for the development of the purulent destructive skin inflammation in HS. Recent findings suggest a key role of the immune mediators IL-1β, IL-17A and G-CSF in the migration into and activation of neutrophils in the skin. Although phytomedical drugs display potent immunoregulatory properties and have been suggested as complementary therapy in several chronic disorders, their application in HS has not been considered so far. In this review, we describe the IL-1/IL-17/G-CSF axis and evaluate it as potential target for an integrated phytomedical treatment of HS.

Hidradenitis-suppurativa-bedingte Kosten, ein Plädoyer für Aufmerksamkeit: eine systematische Literaturübersicht

Die Daten zu Hidradenitis suppurativa (HS)-bedingten Kosten sind begrenzt und inhomogen. Sie sind jedoch erheblich. Wir führten eine systematische Sichtung der Literaturberichte durch, in denen finanzielle Daten über jeden Gesundheitsbereich oder andere Ausgaben dokumentiert wurden, die durch HS und/oder HS-bedingte Auswirkungen auf Beschäftigung, Einkommen und persönliches wirtschaftliche Entwicklung entstanden sind (indirekte Kosten). Dafür wurden drei elektronische Datenbanken durchsucht (MEDLINE, ScienceDirect und die Cochrane Library -letzte Suche: 14. September 2021). Alle Kosten wurden inflationsbereinigt (2022) und in US-Dollar umgerechnet. Es wurden 23 Artikel eingeschlossen (18 Krankheitskostenstudien, 4 Beobachtungsstudien und 1 Fallserie), in denen ökonomische Daten von 77.287 HS-Patienten erfasst wurden. Die durch HS entstandenen durchschnittlichen jährlichen Kosten pro Patient reichten von 258 $ bis 8.078 $. Diese Zahl erhöhte sich bei chirurgischen Eingriffen, Krankheitsprogression, Antibiotika-Versagen und bestimmten Begleitkrankheiten. Der kostspieligste Faktor war die stationäre Versorgung, gefolgt von ambulanter und Notfallversorgung. Signifikante Unterschiede wurden zwischen den USA und den übrigen untersuchten Ländern beobachtet. Im Vergleich zu Psoriasis-Patienten waren Krankenhausaufenthalte bei HS wahrscheinlicher, länger und kostspieliger, während die weniger kostspielige ambulante Versorgung bei HS-Patienten verringert war. Das Vermeiden der Krankheitsprogression durch frühzeitige Diagnose und Optimierung der ambulanten dermatologischen Versorgung könnte HS-bedinge Ausgaben reduzieren.

Hidradenitis suppurativa-related expenditure, a call for awareness: systematic review of literature

Data regarding hidradenitis suppurativa (HS)-related expenditure is limited and non-homogeneous, but HS does incur significant expenses. We performed a systematic review of literature reports documenting financial data regarding any healthcare domain or other expenditure incurred by HS and/or HS impact on work, income and personal economic growth (indirect costs). Three electronic databases were searched (MEDLINE, ScienceDirect, and the Cochrane Library - last search date: September 14^th , 2021). All costs were adjusted for inflation (2022) and converted into US dollars. Twenty-three papers were included (18 cost-of-illness studies, 4 observational studies and 1 case series), drawing economic data from 77,287 HS patients. The total mean cost incurred by HS per patient per year ranged from $ 258 to $ 8,078. This number increased in case of surgical intervention, disease progression, antibiotic failure and certain comorbid diseases. The costliest healthcare sector was inpatient care, followed by outpatient and emergency care. Significant differences were observed between the USA and the rest of studied countries. Hospitalization was likelier, lengthier, and costlier for HS compared to psoriasis patients, whereas the less costly outpatient care appeared to be reduced among HS patients. Preventing disease progression by optimizing early diagnosis and dermatology outpatient care could decrease HS-related expenditure.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

[Pathogenesis of hidradenitis suppurativa/acne inversa]

Hidradenitis suppurativa/acne inversa (HS) has a multifactorial pathogenesis. In addition to a sporadic form, a familial form is reported in around 40% of patients, for whom an autosomal dominant (AD) inheritance with reduced gene penetrance is assumed. The phenotype of the disease with inflammatory nodules, abscesses and secreting sinus tracts suggests an infectious origin, but the exact role of the bacteria detected in HS pathogenesis remains unclear. Smoking and metabolic syndrome are regarded as important trigger factors in HS, with obesity and hormonal changes playing a pathogenic role in the latter. Ultimately, Toll-like receptors, antimicrobial peptides, immune cells and key cytokines are involved in the excessive inflammatory reaction of HS and are also the targets of future therapies.

Features Associated With Quality of Life Impairment in Hidradenitis Suppurativa Patients

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease with an adverse impact on patients' quality of life (QoL).

Objectives: To quantify QoL impairment in patients in Germany suffering from HS and to identify the parameters associated with QoL impairment.

Methods: A non-interventional, cross-sectional, mono-centric study with 500 HS patients. QoL data (measured using the Dermatology Life Quality Index; DLQI) and demographic, anamnestic, clinical, and blood parameters were collected. All patients were examined by dermatologists that documented the skin alterations. QoL data from 462 HS patients were available and evaluated.

Results: The mean (± standard deviation) DLQI score of HS patients was 13.18 ± 7.99. Approximately 40% and 20% of HS patients declared very large and extremely large QoL impairment, respectively. The degree of QoL disturbance correlated with the severity of skin alterations, blood leucocyte count and, in particular, with anogenital localization and the presence of nodules and fistulas. Furthermore, QoL impairment was associated with specific comorbidities, such as adiposity and back pain, but not with HS family history. QoL impairment was not influenced by whether or not the patients had undergone resection surgery or antibiotic treatment but was more severe in HS patients that had undergone abscess lancing compared to patients without such treatment in the past.

Limitations: It was a mono-centric study and most data were obtained from self-administered patient questionnaires. The association of QoL with type of treatment was analyzed for abscess lancing, resection surgery, and antibiotic treatment. Further therapeutic modalities recommended in the guidelines were not investigated.

Conclusion: A profound impairment in QoL was present in patients with HS, and this was higher than that observed in other studied dermatoses. The degree of impairment correlated with the extent of cutaneous and some extra-cutaneous alterations. Surgical and conventional medicamentous therapies of HS were not associated with long-lasting reduction of QoL impairment. Our data support the implementation of patient-reported outcome measures for the assessment of therapy responses.

Quality-of-Life Impairment among Patients with Hidradenitis Suppurativa: A Cross-Sectional Study of 1795 Patients

The chronic, inflammatory skin disorder hidradenitis suppurativa (HS) is associated well documented negative influences on patients' quality of life (QoL). The aim of this study was to present more robust data on patients' QoL impairment by demographic data and its correlation with well-known HS risk factors on a cohort of 1795 German patients. The instrument used for measuring QoL in this study was the Dermatology Life Quality Index (DLQI). Overall, patients reported a very large effect of HS on their QoL (mean DLQI: 13.2 ± 8.1 points), and 22% of the analyzed population even reported to consider the effect as extremely large. Women tended to experience significantly higher impairment than men (p < 0.001). QoL impairment correlated positively with pain (r = 0.581, p < 0.001), HS severity (measured by the International Hidradenitis Suppurativa Severity Score System (IHS4)) as well as Hurley. Neck involvement tended to decrease QoL significantly more than any other location (14.7 ± 8.3 points). This study confirms the enormous influence of HS on patients' QoL in a large cohort. Knowledge of QoL impairment in such patients is crucial for proper understanding and holistic management of this disease.

Aetiology and pathogenesis of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disorder. Patients develop inflamed nodules and abscesses and, at later stages of disease, epithelialized tunnels and scars in skinfolds of axillary, inguinal, gluteal and perianal areas. Quality of life is affected due to severe pain, purulent secretion, restricted mobility and systemic involvement. Genetics and lifestyle factors including smoking and obesity contribute to the development of HS. These factors lead to microbiome alteration, subclinical inflammation around the terminal hair follicles, and infundibular hyperkeratosis, resulting in plugging and rupture of the follicles. Cell-damage-associated molecules and propagating bacteria trigger inflammation and lead to massive immune cell infiltration that clinically manifests as inflamed nodules and abscesses. The immune system plays a key role also in the progression and chronification of skin alterations. Innate proinflammatory cytokines (e.g. interleukin-1β and tumour necrosis factor-α), mediators of activated T helper (Th)1 and Th17 cells (e.g. interleukin-17 and interferon-γ), and effector mechanisms of neutrophilic granulocytes, macrophages and plasma cells are involved. Simultaneously, skin lesions contain anti-inflammatory mediators (e.g. interleukin-10) and show limited activity of Th22 and regulatory T cells. The inflammatory vicious circle finally results in pain, purulence, tissue destruction and scarring. Chronic inflammation in patients with HS is also frequently detected in organs other than the skin, as indicated by their comorbidities. All these aspects represent a challenge for the development of therapeutic approaches, which are urgently needed for this debilitating disease. This scholarly review focuses on the causes and pathogenetic mechanisms of HS and the potential therapeutic value of this knowledge.