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Hidradenitis suppurativa (HS) Learning Zone
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HS Overview

Declaration of sponsorship Novartis Pharma AG
Read time: 100 mins
Last updated:16th Sep 2021
Published:16th Sep 2021

Hidradenitis suppurativa (HS) is a physically painful and psychologically distressing systemic disease. Explore:

  • The symptoms and immense burden in our interview with Dr Joslyn Kirby
  • Pathophysiological mechanisms in our infographics of early and advanced disease
  • Diagnostic techniques and the need for earlier diagnosis

HS epidemiology

Estimates of the prevalence of hidradenitis suppurativa (HS) vary widely and are determined by the method of data collection1. Currently, assessments of three main types of studies are used to produce estimates of prevalence and give important insights into the populations impacted by this disease; self-reporting, registry-based, and group examination studies1.

What is the global prevalence of hidradenitis suppurativa?

In recent years a range of studies have estimated the global prevalence of hidradenitis suppurativa as being between 0.00033–4.1% and more recent studies in the United States and Europe have potentially narrowed this range to 0.7–1.2%2–15.

However, in a systematic review and meta-analysis (N = 118,760,093) of hidradenitis suppurativa cases, differences in prevalence were found when stratifying by geographic region (Figure 1)16. The highest prevalence was seen in Europe 0.8% (0.5–1.3%), followed by the USA 0.2% (0.1–0.4%), Asia-Pacific 0.2% (0.01–2.2%), and South America 0.2% (0.01–0.9%)16.

T1 HS_Fig1.png

Figure 1. Forest plot of pooled hidradenitis suppurativa prevalence, stratified by geographic region (Adapted16).

One of the studies included in the systematic review and meta-analysis was a population-based observational and case–control study of hospital episode statistics from the UK Clinical Practice Research Datalink (CPRD)9.

In this study, it was also found that around 30% of hidradenitis suppurativa patients were previously unrecognised and 18,417 cases had a history of 1–4 flexural skin boils, potentially giving rise to a higher prevalence of 1.19%9.

Hidradenitis suppurativa is often underdiagnosed and has a worldwide mean diagnostic delay of approximately seven years17

The results from these studies broadly align with data collected across various western European countries that have utilised self-reporting through validated questionnaires15. However, selection and classification bias may impact the reliability of prevalence estimates as they are dependent on data from secondary and tertiary-level health care institutions18.

Does hidradenitis suppurativa prevalence differ by demographic?

In paediatric patients and adults, hidradenitis suppurativa appears to exhibit similar clinical features and endocrine comorbidities19,20. However, hidradenitis suppurativa is most highly prevalent between the third and fourth decades of life2,3,8,21–23. Moreover, hidradenitis suppurativa appears to be very rare in women before menarche, although paediatric cases have been described24.

In the study by Ingram et al., it was also noted that the peak hidradenitis suppurativa prevalence of 15.1 per 1,000 occurred in the fifth decade of life (Figure 2). It was also shown that the mean female to male ratio was 2.9 to 1 across the age groups9.

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HS symptoms

Explore how HS develops from early to late stages as well as the importance of engaging patients and finding the right treatment for every patient.

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic, inflammatory disorder of the skin that is defined by the nature and localisation of the skin alterations18. An understanding of the symptoms can both aid diagnosis and promote recognition of the immense burden of this disease.

What are the symptoms of hidradenitis suppurativa?

Patients with hidradenitis suppurativa develop painful and inflamed nodules, abscesses and pus-discharging tunnels (known as sinus tracts and fistulas) between skin folds of the armpits, groin, gluteal, and perianal areas of the body34.

The most impactful symptom reported by almost all hidradenitis suppurativa patients is chronic pain, which ranges from mild to moderate intensity35. Usually resulting from the inflammatory nodules or abscesses associated with the disease, pain is reported by 97% of patients during their disease course35.

Studies have shown that compared to other dermatological conditions, the pain associated with hidradenitis suppurativa may be of a higher intensity36–38

This pain has been described by patients as hot, burning, pressing, stretching, cutting, sharp, taut, splitting, gnawing, sore, throbbing or aching35,36.

Due to the severe pain and purulent secretions that restrict movement and produce an unpleasant smell, the physical manifestation of hidradenitis suppurativa profoundly impacts the lives of patients39.

T1 HS_Fig3.png

Figure 3. Common skin on skin locations in which hidradenitis suppurativa can develop (Adapted40).

Pruritus is also a frequently mentioned symptom39, which has been shown in two previous studies to have a prevalence of 41.2–67.6%35,41. Although no specific correlation was found between pruritus intensity and disease severity, the intensity of the pruritus was associated with a negative impact on quality of life35,41.

How do the symptoms of hidradenitis suppurativa progress?

When hidradenitis suppurativa begins to develop, it usually progresses through the following stages:

  • Area of skin feels uncomfortable
  • Tender, deep nodule(s) appear
  • Nodule(s) grow and start to join together
  • Large, painful, abscesses break open
  • Blackhead-like spots
  • Abscesses heal slowly (if at all) and return; scars form

Comparatively little is known about the long-term evolution of hidradenitis suppurativa. Some studies using self-reported real-world data have shown that approximately one third of patients achieve remission, while one third remain unchanged or worsen. One third also achieve amelioration, possibly due to improved coping over time42.

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HS burden of disease

Join Dr Joslyn Kirby to find out about the impact of hidradenitis suppurativa on patients and the large psychological burden they face.

Hidradenitis suppurativa has a substantially negative impact on quality of life that can persist for years due to an immense physical and psychological burden, including painful lesions, stigmatisation, and an increased risk of suicide39,46,47.

How does hidradenitis suppurativa impact quality of life?

According to studies of quality of life impairment, patients with hidradenitis suppurativa have greatly reduced physical and mental health (Figure 4)37,48.

T1 HS_Fig4.png

Figure 4. Impact of hidradenitis suppurativa on patient quality of life as measured by the Short Form 36 items survey, with scores representing the percentage of the total possible score achieved (Adapted39).

Using Short Form 36 items survey (SF-36) general health questionnaire scores, these studies have found that the domains with notably lower scores were role physical, bodily pain, general health, perception, social functioning, and role emotional compared to the general population37,48.

Patients have reported negative impacts on their sex life49 as well as their professional lives, which can negatively affect their economic situation50,51

In more severe disease (Hurley stage III), physical functioning, vitality, and mental health were also found to be significantly deteriorated48.

Collectively, these burdens can have an immense negative impact on the quality of life of the patient. Notably, a psychological burden is especially prevalent in hidradenitis suppurativa patients due to this impact on quality of life52.

What is the psychological burden of hidradenitis suppurativa?

Patients with dermatoses are generally considered to be at a higher risk of psychiatric disorders compared to the overall population52,53. However, patients with hidradenitis suppurativa are thought to be particularly at risk, due to the impact on quality of life caused by their symptoms and associated comorbidities52.

A Finnish nationwide registry study (N = 4,381) aimed to clarify the association between hidradenitis suppurativa and its psychiatric comorbidities. In the study, hidradenitis suppurativa patients were compared to patients with psoriasis, due to their elevated risk of psychological comorbidities, and melanocytic nevi52.

It was found that the total prevalence of psychotic disorders was 4.7% in the hidradenitis suppurativa group compared with 3.3% in the psoriasis group (OR 1.46, 95% CI 1.24–1.72) and 1.7% in the melanocytic nevi group (OR 2.74, 95% CI 2.29–3.28)52.

Notably, gender differences were observed (Figure 5) with mental disorders being more frequently observed in female (OR 1.28; 95% CI 1.15–1.41) than male (OR 1.46, 95% CI 1.28–1.66) patients with hidradenitis suppurativa (25.5% and 22.0%, respectively).

T1 HS_Fig5.png

Figure 5. Gender differences in the odds ratios for psychiatric disorders in hidradenitis suppurativa patients (Adapted52). CI, confidence interval.

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HS pathophysiology

Gain an overview of these complex pathophysiological mechanisms in our expert interview with Dr Joslyn Kirby.

The current understanding of the pathophysiology of hidradenitis suppurativa is limited18. The underlying pathological mechanisms of hidradenitis suppurativa (HS) appear to be complex and multifaceted, simultaneously involving neutrophilic dermatosis, a strong anti-inflammatory component, and the potential involvement of B cells, TH1 cells, and TH17 cells18.

How does hidradenitis suppurativa develop?

Beginning at the hair follicle, the earliest histologically detectable events in hidradenitis suppurativa include18:

  • Perivascular and perifollicular immune cell infiltration
  • Hyperkeratosis
  • Hyperplasia of the infundibular epithelium (infundibular acanthosis)

These alterations of the infundibular epithelium induce follicular occlusion, or ‘plugging’, followed by a stasis of follicular content, anaerobic bacterial proliferation, and hair follicle dilatation (Figure 1)18.

Specific causes of the HS pathogenetic process have yet to be determined. However, various trigger factors have been implicated including lifestyle factors, genetic predisposition, intertriginous skin type, and specific microbiota18

As follicular cells become damaged, bacterial components and danger-associated molecular patterns (DAMPs) are released, which may further stimulate inflammatory responses. It has been suggested that local macrophages may become activated, leading to the secretion of pro-inflammatory cytokines, such as interleukin (IL)-1β and tumour necrosis factor (TNF)(Figure 6)18.

T1 HS_Fig6.png

Figure 6. Initial events involved in the pathogenesis of hidradenitis suppurativa (Adapted18). AP-1, activator protein 1; CCL, chemokine (C-C motif) ligand; CXCL, chemokine (C-X-C motif) ligand; IL, interleukin; NF-κB, nuclear factor-κB; NLRP3, NACHT, LRR and PYD domain-containing protein 3; TH, T helper; TLR, toll-like receptor; TNF, tumour necrosis factor.

Bacterial sensing may also be strengthened through the increased expression of Toll-like receptor 2 (TLR2) by local macrophages or dendritic cells18.

Once secreted, IL-1β and TNF act on various cell types with partially overlapping effects (Figure 6). IL-1β induces the production of chemokines, with the most prominent chemokines attracting neutrophilic granulocytes. TNF activates endothelial cells, causing a stronger expression of adhesion molecules, and also stimulates an assortment of chemokines that attract neutrophils, T cell subsets, and monocytes into the skin18.

The importance of TNF involvement in the initial pathogenic events of HS is highlighted by patient responses to anti-TNF therapy18

The induction of chemokines and endothelial cell activation leads to an intense infiltration of immune cells into the developing lesions followed by the development of monocytes into macrophages and dendritic cells18.

While their precise role in the pathogenesis of hidradenitis suppurativa has yet to be elucidated, various other cells are also seen to be prevalent in hidradenitis suppurativa lesions, including18:

  • Mast cells
  • Natural killer cells
  • B cells
  • Plasma cells

Notably, hidradenitis suppurativa differs from other immune-mediated skin disorders, such as psoriasis, due to the strong expression of the anti-inflammatory mediator IL-1018.

In patients with hidradenitis suppurativa who also smoke tobacco, nicotine can increase intracellular cAMP levels, possibly enhancing cutaneous IL-10 production18

Following induction by pro-inflammatory cytokines, such as TNF, IL-10 in macrophages can inhibit immune responses by suppressing monocyte and macrophage pro-inflammatory cytokine production. This leads, both directly and indirectly, to a reduced T cell activation18.

When does hidradenitis suppurativa progress?

The sequential progression of hidradenitis suppurativa is still poorly understood. However, the events seen in advanced disease can be distinguished from the initial pathogenic events (Figure 2)18.

As hidradenitis suppurativa progresses, a diverse range of immune cells permeate the skin and secrete specific cytokines18

In the skin of hidradenitis suppurativa patients, T cells produce high levels of interferon-γ (IFNγ) and IL-17, similar to the levels seen in psoriasis patients. In a previous study, CD4+ T cell enrichment was shown to secrete IFNγ and IL-17 in ex vivo experiments, implying that T helper (TH) cells can produce these mediators18.

IL-12 and IL-23 are also present within the skin of hidradenitis suppurativa patients. These cytokines support the function of TH1 and TH17 cells and can be produced by dendritic cells or macrophages18.

IFNγ activates macrophages and tissue cells, which may be essential for local T cell activation18

In the hidradenitis suppurativa lesions, the infiltration of immune cells from blood vessels is triggered by the activation of dermal endothelial cells by IFNγ. A positive feedback loop then forms, with IFNγ inducing the secretion chemokines, such as CXCL10, that attract TH1 cells (Figure 7)18.

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HS diagnosis

Join Dr Joslyn Kirby to discover the factors that can influence the risk of developing HS, including genetics and lifestyle.

Appropriate early dentification and treatment of hidradenitis suppurativa is essential for minimising the risk of disease progression and the development of associated comorbidities.

However, as emerging hidradenitis suppurativa lesions appear similar to other disorders, such as abscesses or boils, the disease is often underdiagnosed and has led to a worldwide mean diagnostic delay of approximately seven years17.

How do you diagnose hidradenitis suppurativa?

Hidradenitis suppurativa diagnosis is based on the nature and location of skin lesions as well as the disease course, which can be defined as persistent (lesions present for at least 6 months) or recurrent (>2 skin lesions occurring or recurring within 6 months)34,60.

Large international studies have shown that there is an average delay of 7–10 years between the onset of disease and the diagnosis17,43

Typical hidradenitis suppurativa skins lesions are characterised by purulence, malodorous discharge, pain, and discomfort during daily life activities34.

The location and type of these lesions are used to support the diagnosis of hidradenitis suppurativa. Patients may present with one or multiple types of lesions simultaneously, which typically include60:

  • Inflammatory nodules
  • Abscesses
  • Inflamed and draining sinus tracts or fistulas
  • Rope-like scarring
  • Open comedones
  • Bridged scars
  • Post-inflammatory double-ended pseudocomedones (resembling a ‘tombstone’)

Lesions generally appear in intertriginous areas or other areas such as the nape of the neck, the trunk, extremities, or the retroauricular area. However, the location of these lesions in specific areas of the body is influenced by biological sex (Table 1)7,61,62.

Table 1. Differences in hidradenitis suppurativa lesion prevalence between men and women (Adapted7,61,62).

Lesions with higher prevalence in men  Lesions with higher prevalence in women 
• Armpits 
• Perineal or perianal regions 
• Buttocks 
• Gluteal cleft
• Groin, specifically upper inner thigh 
• Submammary regions 
• Inframammary regions 

A family history can also be used to support the diagnosis of hidradenitis suppurativa accompanied by various additional clinical signs, including recurrent atypical lesions in intertriginous areas, such as folliculitis and open comedones; the presence or history of a pilonidal sinus; and typical lesions in atypical locations, such as the inner thigh or the waist61,63.

What diagnostics can be used for hidradenitis suppurativa?

In cases of hidradenitis suppurativa that are uncertain, biopsies can be used to reject other potential disorders, such as pyoderma gangrenosum, squamous cell carcinoma or lymphomas18. However, skin biopsies are not usually required for the diagnosis of hidradenitis suppurativa18.

The type of alteration determines the histopathological characteristics of hidradenitis suppurativa. These can range from early cysts, nodules or abscesses to inflamed sinus tracts or rope-like scars64. In ruptured cysts, pan-keratin immunostaining as well as haematoxylin and eosin staining can also be used to visualise the keratin fragments and debris that become dispersed in the dermis65.

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  1. Jemec GBE, Kimball AB. Hidradenitis suppurativa: Epidemiology and scope of the problem. J Am Acad Dermatol. 2015;73(5):S4–S7.
  2. Calao M, Wilson JL, Spelman L, Billot L, Rubel D, Watts AD, et al. Hidradenitis Suppurativa (HS) prevalence, demographics and management pathways in Australia: A population-based cross-sectional study. PLoS One. 2018;13(7). doi:10.1371/journal.pone.0200683.
  3. Cosmatos I, Matcho A, Weinstein R, Montgomery MO, Stang P. Analysis of patient claims data to determine the prevalence of hidradenitis suppurativa in the United States. J Am Acad Dermatol. 2013;68(3):412–419.
  4. Ianhez M, Schmitt J V., Miot HA. Prevalence of hidradenitis suppurativa in Brazil: a population survey. Int J Dermatol. 2018;57(5):618–620.
  5. Fania L, Ricci F, Sampogna F, Mazzanti C, Didona B, Pintori G, et al. Prevalence and incidence of hidradenitis suppurativa: an exercise on indirect estimation from psoriasis data. J Eur Acad Dermatology Venereol. 2017;31(9):e410–e411.
  6. Delany E, Gormley G, Hughes R, McCarthy S, Kirthi S, Markham T, et al. A cross-sectional epidemiological study of hidradenitis suppurativa in an Irish population (SHIP). J Eur Acad Dermatology Venereol. 2018;32(3):467–473.
  7. Vazquez BG, Alikhan A, Weaver AL, Wetter DA, Davis MD. Incidence of hidradenitis suppurativa and associated factors: A population-based study of Olmsted County, Minnesota. J Invest Dermatol. 2013;133(1):97–103.
  8. Jemec GBE, Heidenheim M, Nielsen NH. The prevalence of hidradenitis suppurativa and its potential precursor lesions. J Am Acad Dermatol. 1996;35(2 PART I):191–194.
  9. 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.
  10. Miller IM, McAndrew RJ, Hamzavi I. Prevalence, Risk Factors, and Comorbidities of Hidradenitis Suppurativa. Dermatol Clin. 2016;34(1):7–16.
  11. Andersen LK, Davis MDP. Prevalence of Skin and Skin-Related Diseases in the Rochester Epidemiology Project and a Comparison with Other Published Prevalence Studies. Dermatology. 2016;232(3):344–352.
  12. Sung S, Kimball AB. Counterpoint: Analysis of patient claims data to determine the prevalence of hidradenitis suppurativa in the United States. J Am Acad Dermatol. 2013;69(5):818–819.
  13. 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 Dermatology. 2017;153(8):760–764.
  14. Ingvarsson G. Regional variation of hidradenitis suppurativa in the Norwegian Patient Registry during a 5-year period may describe professional awareness of the disease, not changes in prevalence. Br J Dermatol. 2017;176(1):274–275.
  15. Theut Riis P, Pedersen OB, Sigsgaard V, Erikstrup C, Paarup HM, Nielsen KR, et al. Prevalence of patients with self-reported hidradenitis suppurativa in a cohort of Danish blood donors: a cross-sectional study. Br J Dermatol. 2019;180(4):774–781.
  16. Phan K, Charlton O, Smith SD. Global prevalence of hidradenitis suppurativa and geographical variation—systematic review and meta-analysis. Biomed Dermatology. 2020;4(1):1–6.
  17. Saunte DM, Boer J, Stratigos A, Szepietowski JC, Hamzavi I, Kim KH, et al. Diagnostic delay in hidradenitis suppurativa is a global problem. Br J Dermatol. 2015;173(6):1546–1549.
  18. Sabat R, Jemec GBE, Matusiak Ł, Kimball AB, Prens E, Wolk K. Hidradenitis suppurativa. Nat Rev Dis Prim. 2020;6(1). doi:10.1038/s41572-020-0149-1.
  19. Braunberger TL, Nicholson CL, Gold L, Nahhas AF, Jacobsen G, Parks-Miller A, et al. Hidradenitis suppurativa in children: The Henry Ford experience. Pediatr Dermatol. 2018;35(3):370–373.
  20. Liy-Wong C, Pope E, Lara-Corrales I. Hidradenitis suppurativa in the pediatric population. J Am Acad Dermatol. 2015;73(5):S36–S41.
  21. Fabbrocini G, De Vita V, Donnarumma M, Russo G, Monfrecola G. South Italy: A Privileged Perspective to Understand the Relationship between Hidradenitis Suppurativa and Overweight/Obesity. Ski Appendage Disord. 2016;2(1–2):52–56.
  22. Katoulis AC, Liakou AI, Rotsiamis N, Bonovas S, Bozi E, Rallis E, et al. Descriptive Epidemiology of Hidradenitis Suppurativa in Greece: A Study of 152 Cases. Ski Appendage Disord. 2017;3(4):197–201.
  23. de Andrade TCPC, Vieira BC, Oliveira AMN, Martins TY, Santiago TM, Martelli ACC. Hidradenitis suppurativa: Epidemiological study of cases diagnosed at a dermatological reference center in the city of Bauru, in the Brazilian southeast state of São Paulo, between 2005 and 2015. An Bras Dermatol. 2017;92(2):196–199.
  24. Deckers IE, Van Der Zee HH, Boer J, Prens EP. Correlation of early-onset hidradenitis suppurativa with stronger genetic susceptibility and more widespread involvement. J Am Acad Dermatol. 2015;72(3):485–488.
  25. Kurokawa I, Hayashi N. Questionnaire surveillance of hidradenitis suppurativa in Japan. J Dermatol. 2015;42(7):747–749.
  26. Sabat R, Chanwangpong A, Schneider-Burrus S, Metternich D, Kokolakis G, Kurek A, et al. Increased prevalence of metabolic syndrome in patients with Acne inversa. PLoS One. 2012;7(2). doi:10.1371/journal.pone.0031810.
  27. Yang JH, Moon J, Kye YC, Kim KJ, Kim MN, Ro YS, et al. Demographic and clinical features of hidradenitis suppurativa in Korea. J Dermatol. 2018;45(12):1389–1395.
  28. Lee DE, Clark AK, Shi VY. Hidradenitis Suppurativa: Disease Burden and Etiology in Skin of Color. Dermatology. 2018;233(6):456–461.
  29. Udechukwu NS, Fleischer AB. Higher Risk of Care for Hidradenitis Suppurativa in African American and Non-Hispanic Patients in the United States. J Natl Med Assoc. 2017;109(1):44–48.
  30. Vlassova N, Kuhn D, Okoye GA. Hidradenitis suppurativa disproportionately affects African Americans: A single-center retrospective analysis. Acta Derm Venereol. 2015;95(8):990–991.
  31. Reeder VJ, Mahan MG, Hamzavi IH. Ethnicity and hidradenitis suppurativa. J Invest Dermatol. 2014;134(11):2842–2843.
  32. Vaidya T, Vangipuram R, Alikhan A. Examining the race-specific prevalence of hidradenitis suppurativa at a large academic center; results from a retrospective chart review. Dermatol Online J. 2017;23(6):12–13.
  33. Garg A, Lavian J, Lin G, Strunk A, Alloo A. Incidence of hidradenitis suppurativa in the United States: A sex- and age-adjusted population analysis. J Am Acad Dermatol. 2017;77(1):118–122.
  34. Saunte DML, Jemec GBE. Hidradenitis suppurativa: Advances in diagnosis and treatment. JAMA - J Am Med Assoc. 2017;318(20):2019–2032.
  35. Matusiak Ł, Szczęch J, Kaaz K, Lelonek E, Szepietowski JC. Clinical characteristics of pruritus and pain in patients with hidradenitis suppurativa. Acta Derm Venereol. 2018;98(2):191–194.
  36. Smith HS, Chao JD, Teitelbaum J. Painful hidradenitis suppurativa. Clin J Pain. 2010;26(5):435–444.
  37. Wolkenstein P, Loundou A, Barrau K, Auquier P, Revuz J. Quality of life impairment in hidradenitis suppurativa: A study of 61 cases. J Am Acad Dermatol. 2007;56(4):621–623.
  38. Onderdijk AJ, Van Der Zee HH, Esmann S, Lophaven S, Dufour DN, Jemec GBE, et al. Depression in patients with hidradenitis suppurativa. J Eur Acad Dermatology Venereol. 2013;27(4):473–478.
  39. Matusiak. Profound consequences of hidradenitis suppurativa: a review. Br J Dermatol. 2020;183(6):e171–e177.
  40. American Academy of Dermatology Association (AAD). Hidradenitis suppurativa: Signs and symptoms. Accessed 19 July 2021.
  41. Vossen ARJV, Schoenmakers A, van Straalen KR, Prens EP, van der Zee HH. Assessing Pruritus in Hidradenitis Suppurativa: A Cross-Sectional Study. Am J Clin Dermatol. 2017;18(5):687–695.
  42. Kromann CB, Deckers IE, Esmann S, Boer J, Prens EP, Jemec GBE. Risk factors, clinical course and long-term prognosis in hidradenitis suppurativa: A cross-sectional study. Br J Dermatol. 2014;171(4):819–824.
  43. Garg A, Neuren E, Cha D, Kirby JS, Ingram JR, Jemec GBE, et al. Evaluating patients’ unmet needs in hidradenitis suppurativa: Results from the Global Survey Of Impact and Healthcare Needs (VOICE) Project. J Am Acad Dermatol. 2020;82(2):366–376.
  44. Cartron A, Driscoll MS. Comorbidities of hidradenitis suppurativa: A review of the literature. Int J Women’s Dermatology. 2019;5(5):330–334.
  45. Egeberg A, Gislason GH, Hansen PR. Risk of major adverse cardiovascular events and all-cause mortality in patients with hidradenitis suppurativa. JAMA Dermatology. 2016;152(4):429–434.
  46. 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.
  47. Kouris A, Platsidaki E, Christodoulou C, Efstathiou V, Dessinioti C, Tzanetakou V, et al. Quality of Life and Psychosocial Implications in Patients with Hidradenitis Suppurativa. Dermatology. 2017;232(6):687–691.
  48. 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.
  49. Esmann S, Jemec GBE. Psychosocial impact of hidradenitis suppurativa: A qualitative study. Acta Derm Venereol. 2011;91(3):328–332.
  50. Matusiak Ł, Bieniek A, Szepietowski JC. Hidradenitis suppurativa markedly decreases quality of life and professional activity. J Am Acad Dermatol. 2010;62(4). doi:10.1016/j.jaad.2009.09.021.
  51. Theut Riis P, Thorlacius L, Knudsen List E, Jemec GBE. A pilot study of unemployment in patients with hidradenitis suppurativa in Denmark. Br J Dermatol. 2017;176(4):1083–1085.
  52. Huilaja L, Tiri H, Jokelainen J, Timonen M, Tasanen K. Patients with Hidradenitis Suppurativa Have a High Psychiatric Disease Burden: A Finnish Nationwide Registry Study. J Invest Dermatol. 2018;138(1):46–51.
  53. Dalgard FJ, Gieler U, Tomas-Aragones L, Lien L, Poot F, Jemec GBE, et al. The Psychological Burden of Skin Diseases: A Cross-Sectional Multicenter Study among Dermatological Out-Patients in 13 European Countries. J Invest Dermatol. 2015;135(4):984–991.
  54. Raison CL, Capuron L, Miller AH. Cytokines sing the blues: Inflammation and the pathogenesis of depression. Trends Immunol. 2006;27(1):24–31.
  55. Van Der Zee HH, De Ruiter L, Van Den Broecke DG, Dik WA, Laman JD, Prens EP. Elevated levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-10 in hidradenitis suppurativa skin: A rationale for targeting TNF-α and IL-1β. Br J Dermatol. 2011;164(6):1292–1298.
  56. Matusiak Ł, Bieniek A, Szepietowski JC. Increased serum tumour necrosis factor-α in hidradenitis suppurativa patients: Is there a basis for treatment with anti-tumour necrosis factor-α agents? Acta Derm Venereol. 2009;89(6):601–603.
  57. Kurek A, Johanne Peters EM, Sabat R, Sterry W, Schneider-Burrus S. Depression is a frequent co-morbidity in patients with acne inversa. JDDG - J Ger Soc Dermatology. 2013;11(8):743–749.
  58. Matusiak Ł, Bieniek A, Szepietowski JC. Psychophysical aspects of hidradenitis suppurativa. Acta Derm Venereol. 2010;90(3):264–268.
  59. Matusiak Ł, Jemec GB, Szepietowski JC. Pharmacological development in hidradenitis suppurativa. Curr Opin Pharmacol. 2019;46:65–72.
  60. Freysz M, Jemec GBE, Lipsker D. A systematic review of terms used to describe hidradenitis suppurativa. Br J Dermatol. 2015;173(5):1298–1300.
  61. Schrader AMR, Deckers IE, Van Der Zee HH, Boer J, Prens EP. Hidradenitis suppurativa: A retrospective study of 846 Dutch patients to identify factors associated with disease severity. J Am Acad Dermatol. 2014;71(3):460–467.
  62. Revuz J. Hidradenitis suppurativa. J Eur Acad Dermatology Venereol. 2009;23(9):985–998.
  63. Boer J. Should Hidradenitis Suppurativa Be Included in Dermatoses Showing Koebnerization? Is It Friction or Fiction? Dermatology. 2017;233(1):47–52.
  64. Jemec GBE, Hansen U. Histology of hidradenitis suppurativa. J Am Acad Dermatol. 1996;34(6):994–999.
  65. Van Der Zee HH, De Ruiter L, Boer J, Van Den Broecke DG, Den Hollander JC, Laman JD, et al. Alterations in leucocyte subsets and histomorphology in normal-appearing perilesional skin and early and chronic hidradenitis suppurativa lesions. Br J Dermatol. 2012;166(1):98–106.
  66. Wortsman X, Moreno C, Soto R, Arellano J, Pezo C, Wortsman J. Ultrasound in-depth characterization and staging of hidradenitis suppurativa. Dermatologic Surg. 2013;39(12):1835–1842.
  67. Virgilio E, Bocchetti T, Balducci G. Utility of MRI in the diagnosis and post-treatment evaluation of anogenital hidradenitis suppurativa. Dermatologic Surg. 2015;41(7):865–866.
  68. Davidson TM. Dermatologic Surgery. 1989. CRC Press doi:10.1288/00005537-198909000-00019.
  69. Horváth B, Janse IC, Blok JL, Driessen RJB, Boer J, Mekkes JR, et al. Hurley staging refined: A proposal by the dutch hidradenitis suppurativa expert group. Acta Derm Venereol. 2017;97(3):412–413.
  70. Kimball AB, Kerdel F, Adams D, Mrowietz U, Gelfand JM, Gniadecki R, et al. Adalimumab for the treatment of moderate to severe hidradenitis suppurativa: A parallel randomized trial. Ann Intern Med. 2012;157(12):846–855.
  71. Sartorius K, Emtestam L, Jemec GBE, Lapins J. Objective scoring of hidradenitis suppurativa reflecting the role of tobacco smoking and obesity. Br J Dermatol. 2009;161(4):831–839.
  72. Zouboulis CC, Tzellos T, Kyrgidis A, Jemec GBE, Bechara FG, Giamarellos-Bourboulis EJ, et al. Development and validation of the International Hidradenitis Suppurativa Severity Score System (IHS4), a novel dynamic scoring system to assess HS severity. Br J Dermatol. 2017;177(5):1401–1409.
  73. Kokolakis G, Sabat R. Distinguishing mild, moderate, and severe hidradenitis suppurativa. JAMA Dermatology. 2018;154(8):971–972.
  74. Hessam S, Scholl L, Sand M, Schmitz L, Reitenbach S, Bechara FG. A novel severity assessment scoring system for hidradenitis suppurativa. JAMA Dermatology. 2018;154(3):330–335.
  75. Pedersen CB, McHorney CA, Larsen LS, Lophaven KW, Moeller AH, Reaney M. Reliability and validity of the Psoriasis Itch Visual Analog Scale in psoriasis vulgaris. J Dermatolog Treat. 2017;28(3):213–220.
  76. Kimball AB, Naegeli AN, Edson-Heredia E, Lin CY, Gaich C, Nikaï E, et al. Psychometric properties of the Itch Numeric Rating Scale in patients with moderate-to-severe plaque psoriasis. Br J Dermatol. 2016;175(1):157–162.
  77. Ferreira-Valente MA, Pais-Ribeiro JL, Jensen MP. Validity of four pain intensity rating scales. Pain. 2011;152(10):2399–2404.
  78. Chernyshov P V. The Evolution of Quality of Life Assessment and Use in Dermatology. Dermatology. 2019;235(3):167–174.
  79. Matusiak Ł, Salomon J, Nowicka-Suszko D, Bieniek A, Szepietowski JC. Chitinase-3-like protein 1 (YKL-40): Novel biomarker of hidradenitis suppurativa disease activity? Acta Derm Venereol. 2015;95(6):736–737.
  80. Tsaousi A, Witte E, Witte K, Röwert-Huber HJ, Volk HD, Sterry W, et al. MMP8 Is Increased in Lesions and Blood of Acne Inversa Patients: A Potential Link to Skin Destruction and Metabolic Alterations. Mediators Inflamm. 2016;2016. doi:10.1155/2016/4097574.
  81. Wolk K, Wenzel J, Tsaousi A, Witte-Händel E, Babel N, Zelenak C, et al. Lipocalin-2 is expressed by activated granulocytes and keratinocytes in affected skin and reflects disease activity in acne inversa/hidradenitis suppurativa. Br J Dermatol. 2017;177(5):1385–1393.
  82. Witte-Händel E, Wolk K, Tsaousi A, Irmer ML, Mößner R, Shomroni O, et al. The IL-1 Pathway Is Hyperactive in Hidradenitis Suppurativa and Contributes to Skin Infiltration and Destruction. J Invest Dermatol. 2019;139(6):1294–1305.
  83. Jiménez-Gallo D, De La Varga-Martínez R, Ossorio-Garciá L, Albarrán-Planelles C, Rodríguez C, Linares-Barrios M. The Clinical Significance of Increased Serum Proinflammatory Cytokines, C-Reactive Protein, and Erythrocyte Sedimentation Rate in Patients with Hidradenitis Suppurativa. Mediators Inflamm. 2017;2017. doi:10.1155/2017/2450401.

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