Improved clinical effectiveness of adalimumab when initiated with clindamycin and rifampicin in hidradenitis suppurativa

BACKGROUND

Adalimumab monotherapy for hidradenitis suppurativa (HS) is often insufficient with a maximum clinical efficacy of 60% in Hidradenitis Suppurativa Clinical Response (HiSCR) and limited effect on draining tunnels. Data suggest that adalimumab therapy could be improved by concomitant antibiotics.

OBJECTIVE

To compare the clinical effectiveness of adalimumab with clindamycin and rifampicin versus adalimumab monotherapy after 12 weeks.

METHODS

This retrospective study included patients who started adalimumab with additional clindamycin and rifampicin and patients treated with adalimumab monotherapy, matched on sex and refined Hurley score. The primary outcome measure was the difference in change in the International Hidradenitis Suppurativa Severity Score System (IHS4) at 12 weeks.

RESULTS

In total, 62 patients were included in the combination therapy group (n = 31) and adalimumab monotherapy group (n = 31), showing comparable IHS4 scores; 32.5 versus 29, p = 0.87 at baseline respectively. The combination therapy demonstrated greater clinical effectiveness expressed in median IHS4 improvement (-20 vs. -9, p < 0.001), IHS4-55 (74% vs. 36%, p = 0.002), median draining tunnel reduction (-4 vs. -2, p < 0.001) and pain response (47% vs. 27%, p = 0.02).

CONCLUSION

Adalimumab initiated with clindamycin and rifampicin shows greater clinical effectiveness than adalimumab monotherapy. An important difference in effect was observed in the decrease of draining tunnels, addressing a serious limitation of adalimumab monotherapy.

Complement activation in Hidradenitis suppurativa: Covert low-grade inflammation or innocent bystander?

Hidradenitis suppurativa (HS) is a chronic auto-inflammatory skin disease with a complex and multifactorial pathogenesis involving both the innate and adaptive immune system. Despite limited evidence for local complement activation, conflicting results have been published on the role of systemic complement activation in HS. It was hypothesized that complement was consumed in highly inflamed HS skin, trapping complement from the circulation. Therefore, the aim of this study was to evaluate this local complement deposition in HS skin lesions using routine and commonly used complement antibodies.Direct immunofluorescence for C1q, C3c, C4d, C5b-9, and properdin was performed on frozen tissue sections of 19 HS patients and 6 controls. C5a receptor 1 (C5aR1) was visualized using immunohistochemistry.

Overall, we found no significant local complement deposition in HS patients versus controls regarding C1q, C3c, C4d, C5b-9, or properdin on either vessels or immune cells. C5aR1 expression was exclusively found on immune cells, predominantly neutrophilic granulocytes, but not significantly different relatively to the total infiltrate in HS lesions compared with controls. In conclusion, despite not being able to confirm local complement depositions of C1q, C3c, C4d, or properdin using highly sensitive and widely accepted techniques, the increased presence of C5aR1 positive immune cells in HS suggests the importance of complement in the pathogenesis of HS and supports emerging therapies targeting this pathway.

Register, multicenter and genome-wide association studies in hidradenitis suppurativa

The European Hidradenitis Suppurativa Foundation (EHSF) e.V. has taken several initiatives to collaborative studies. They result from the data of the European Registry of Hidradenitis Suppurativa (ERHS) based on the knowledge obtained from the regional Northern countries (HISREG) and Italian (IRHIS) registries and the real-world data generated from claims data from insurance databases. Multicenter studies, such as the Hidradenitis Suppurativa collaborative study of subtypes (HORUS) and the Global Hidradenitis Suppurativa Atlas (GHISA) are planned to provide an ideal complement to the register studies. Most recently, the role of EHSF as a coordinator or key player is being explored in multiple genetic studies, such as a genome-wide association study (GWAS) and the exome sequencing and cellular/molecular profiling project, which will speed up gene and drug discovery in HS.

Primary alterations during the development of hidradenitis suppurativa

Background

Hidradenitis suppurativa (HS) is a chronic, inflammatory disease of the apocrine gland‐rich (AGR) skin region. The initial steps of disease development are not fully understood, despite intense investigations into immune alterations in lesional HS skin.

Objectives

We aimed to systematically investigate the inflammatory molecules involved in three stages of HS pathogenesis, including healthy AGR, non‐lesional HS and lesional HS skin, with the parallel application of multiple mRNA and protein‐based methods.

Methods

Immune cell counts (T cells, dendritic cells, macrophages), Th1/Th17‐related molecules (IL‐12B, TBX21, IFNG, TNFA, IL‐17, IL10, IL‐23A, TGFB1, RORC, CCL20), keratinocyte‐related sensors (TLR2,4), mediators (S100A7, S100A8, S100A9, DEFB4B, LCN2, CAMP, CCL2) and pro‐inflammatory molecules (IL1B, IL6, TNFA, IL‐23A) were investigated in the three groups by RNASeq, RT‐qPCR, immunohistochemistry and immunofluorescence.

Results

Epidermal changes were already detectable in non‐lesional HS skin; the epidermal occurrence of antimicrobial peptides (AMPs), IL‐1β, TNF‐α and IL‐23 was highly upregulated compared with healthy AGR skin. In lesional HS epidermis, TNF‐α and IL‐1β expression remained at high levels while AMPs and IL‐23 increased even more compared with non‐lesional skin. In the dermis of non‐lesional HS skin, signs of inflammation were barely detectable (vs. AGR), while in the lesional dermis, the number of inflammatory cells and Th1/Th17‐related mediators were significantly elevated.

Conclusions

Our findings that non‐lesional HS epidermal keratinocytes produce not only AMPs and IL‐1β but also high levels of TNF‐α and IL‐23 confirm the driver role of keratinocytes in HS pathogenesis and highlight the possible role of keratinocytes in the transformation of non‐inflammatory Th17 cells (of healthy AGR skin) into inflammatory cells (of HS) via the production of these mediators. The fact that epidermal TNF‐α and IL‐23 appear also in non‐lesional HS seems to prove these cytokines as excellent therapeutic targets.

Quantitative intracellular oxygen availability before and after 5-aminolevulinic acid skin photodynamic therapy

BACKGROUND

During photodynamic therapy (PDT) oxygen is transformed into reactive oxygen species (ROS) to induce cellular apoptosis in (pre)malignant cells. Real time oxygen availability measurement is clinically available with the Cellular Oxygen Metabolism (COMET) monitor.

METHODS

Primary objective is to show that mitochondrial oxygen availability (mitoPO₂) measurement is possible during clinical ALA-PDT. The secondary aim was to determine the pain sensation, because it is the most commonly reported side effect of PDT. Before and after the two fraction PDT treatment, with a 2-hour dark period, mitoPO₂ was measured and reported pain was documented with a visual analog scale (VAS) 0-100.

RESULTS

Nine patients were included. Before the first PDT session the median signal quality was [IQR] 55.0% [34.2-68.0], which decreased after session one to 0% [0.0-10.0]. MitoPO₂ was 40.0 [17.7-53.8] mmHg and increased afterwards to 61.8 [38.2-64.8] mmHg. This likely the result of the delay time between the illumination stop and the mitoPO₂ measurements in a vasodilated, visibly red lesion. Before session two signal quality was 10.4% [0-20.15], 40% lower than at the start. In 5 patients the signal quality after session 2 was too low because of photobleaching and insufficient regeneration of PpIX, median 0% [0-10]. Subjects reported low median VAS scores, all below 3, directly after the mitoPO₂ measurements.

CONCLUSION

With COMET we were able to reliably measure mitochondrial oxygen concentrations during photodynamic therapy. Signal quality drastically decreases after a PDT session because of PpIX deterioration during the illumination phase.

Adalimumab and infliximab survival in patients with hidradenitis suppurativa: a daily practice cohort study

BACKGROUND

Biologics are often required for the treatment of hidradenitis suppurativa (HS). However, data on the drug survival of biologics in daily practice are currently lacking.

OBJECTIVES

To assess the drug survival of antitumour necrosis factor biologics in a daily practice cohort of patients with HS and to identify predictors for drug survival.

METHODS

A retrospective multicentre study was performed in two academic dermatology centres in the Netherlands. Adult patients with HS using biologics between 2008 and 2020 were included. Drug survival was analysed with Kaplan-Meier survival curves and predictors of survival with univariate Cox regression analysis.

RESULTS

The overall drug survival of adalimumab (n = 104) at 12 and 24 months was 56·3% and 30·5%, respectively, which was predominantly determined by infectiveness. Older age (P = 0·02) and longer disease duration (P < 0·01) were associated with longer survival time. For infliximab (n = 44), overall drug survival was 58·3% and 48·6% at 12 and 24 months, respectively, and was predominantly determined by infectiveness and side-effects. Surgery during treatment was associated with a longer survival time (P = 0·01).

CONCLUSIONS

Survival rates were comparable for adalimumab and infliximab at 12 months, and were mainly determined by ineffectiveness. Age, disease duration (adalimumab) and surgery (infliximab) are predictors for longer survival.

A novel nicastrin mutation in a three-generation Dutch family with hidradenitis suppurativa: a search for functional significance

Background

Mutations in the γ‐secretase enzyme subunits have been described in multiple kindreds with familial hidradenitis suppurativa (HS).

Objective

In this study, we report a novel nicastrin (NCSTN) mutation causing HS in a Dutch family. We sought to explore the immunobiological function of NCSTN mutations using data of the Immunological Genome Project.

Methods

Blood samples of three affected and two unaffected family members were collected. Whole‐genome sequencing was performed using genomic DNA isolated from peripheral blood leucocytes. Sanger sequencing was done to confirm the causative NCSTN variant and the familial segregation. The microarray data set of the Immunological Genome Project was used for thorough dissection of the expression and function of wildtype NCSTN in the immune system.

Results

In a family consisting of 23 members, we found an autosomal dominant inheritance pattern of HS and detected a novel splice site mutation (c.1912_1915delCAGT) in the NCSTN gene resulting in a frameshift and subsequent premature stop. All affected individuals had HS lesions on non‐flexural and atypical locations. Wildtype NCSTN appears to be upregulated in myeloid cells like monocytes and macrophages, and in mesenchymal cells such as fibroblastic reticular cells and fibroblasts. In addition, within the 25 highest co‐expressed genes with NCSTN we identified CAPNS1,ARNT and PPARD.

Conclusion

This study reports the identification a novel NCSTN gene splice site mutation which causes familial HS. The associated immunobiological functions of NCSTN and its co‐expressed genes ARNT and PPARD link genetics to the most common environmental and metabolic HS risk factors which are smoking and obesity.

Highlights of the updated Dutch evidence- and consensus-based guideline on psoriasis 2017

Linked Comment: https://doi.org/10.1111/bjd.17390.

Adalimumab medium-term dosing strategy in moderate-to-severe hidradenitis suppurativa: integrated results from the phase III randomized placebo-controlled PIONEER trials

Background

Weekly adalimumab (Humira^®) is approved for the treatment of hidradenitis suppurativa (HS) based on the 12‐week placebo‐controlled periods of the two phase III PIONEER trials.

Objectives

Using PIONEER integrated trial results, we aimed to evaluate the optimal medium‐term adalimumab maintenance dosing strategy for moderate‐to‐severe HS.

Methods

Each trial had two double‐blind periods; 12‐week Period A and 24‐week Period B. Patients randomized to adalimumab 40 mg every week (ADAew) (Period A), were rerandomized in Period B to ADAew (ADAew/ew), ADA every other week (ADAew/eow), or placebo (ADAew/pbo). Placebo‐randomized patients were reassigned in Period B to ADAew (PIONEER I) or placebo (PIONEER II). The primary outcome was HS Clinical Response (HiSCR). Patients who lost response during Period B were discontinued from the study and offered an option to enter the open‐label extension (OLE) to receive ADAew. Results are reported across the two study periods, and data were combined from the two study periods and the OLE.

Results

For week‐12 HiSCR achievers, the HiSCR week‐36 rate was 48·1% (ADAew/ew) vs. 46·2% (ADAew/eow) and 32·1% (ADAew/pbo). Combining (post hoc) these patients with week‐12 partial responders further differentiated outcomes in Period B (ADAew/ew 55·7% vs. ADAew/eow 40·0% and ADAew/pbo 30·1%). Period‐B adverse‐event rates were ADAew/ew 59·6% vs. ADAew/eow 57·4% and ADAew/pbo 65·0%. One patient (ADAew/ew) reported a serious infection.

Conclusions

Weekly adalimumab treatment, effective throughout 36 weeks, was the optimal maintenance medium‐term dosing regimen for this population. At least partial response after 12 weeks with continued weekly dosing had better outcomes than dose reduction or interruption. Patients who do not show at least a partial response to weekly adalimumab by week 12 are unlikely to benefit from continued therapy. No new safety risks were identified.

What's already known about this topic?

Hidradenitis suppurativa (HS) is a chronic inflammatory disease, commonly misinterpreted as an infection and treated with long‐term antibiotic regimens or surgical incisions.

Based on the chronicity of HS and the lack of evidence for efficacious and safe long‐term HS treatments, it is important to evaluate medium‐ to long‐term therapies for HS.

Weekly adalimumab (Humira^®) is approved for the treatment of moderate‐to‐severe HS based on the two phase III PIONEER trials.

What does this study add?

This study pooled data from the two PIONEER trials, providing a more robust assessment of outcomes.

After at least partial treatment success with weekly adalimumab short‐term therapy (12 weeks), continuing weekly dosing during the subsequent 24 weeks had better outcomes than dose reduction or treatment interruption.

Patients who do not show at least a partial response to weekly adalimumab by week 12 are unlikely to benefit from continued therapy.

Linked Comment: https://doi.org/10.1111/bjd.18437.

https://www.bjdonline.com/article/adalimumab-medium-term-dosing-strategy-in-moderate-to-severe-hidradenitis-suppurativa-integrated-results-from-the-phase-iii-randomized-placebo-controlled-pioneer-t/

The anti-inflammatory potency of biologics targeting tumour necrosis factor-α, interleukin (IL)-17A, IL-12/23 and CD20 in hidradenitis suppurativa: an ex vivo study

Background

Biologics targeting inflammatory mediators can achieve clinical improvements in hidradenitis suppurativa (HS). However, their clinical efficacy shows great interpatient variability in daily practice.

Objectives

To investigate the anti‐inflammatory potency of a selection of currently available biologics and prednisolone for the treatment of HS in an ex vivo skin culture system using lesional HS biopsies.

Methods

Lesional skin samples from 10 patients with HS and skin samples from five healthy controls were cultured ex vivo and exposed to prednisolone or biologics targeting tumour necrosis factor (TNF)‐α, interleukin (IL)‐17A, IL‐12/23p40 or CD20 (adalimumab, infliximab, secukinumab, ustekinumab and rituximab, respectively). Real‐time quantitative polymerase chain reaction and cytokine bead arrays were used to measure the inhibitory effect of the biologics on cytokines and antimicrobial peptides (AMPs).

Results

The relative mRNA expression of all tested cytokines and AMPs was significantly downregulated by all anti‐inflammatory agents (P < 0·001). The protein production of the proinflammatory cytokines TNF‐α, interferon γ, IL‐1β, IL‐6 and IL‐17A was significantly inhibited by adalimumab, infliximab, ustekinumab, prednisolone (all P < 0·001) and rituximab (P = 0·0071), but not by secukinumab (P = 0·0663). On both mRNA and protein levels, adalimumab, infliximab and prednisolone reduced the levels of a broader mix of individual cytokines than secukinumab, ustekinumab and rituximab. Moreover, a significant inhibitory effect on mRNA expression levels of inflammatory markers in healthy control skin was observed only for TNF‐α inhibitors (P < 0·001) and prednisolone (P = 0·0015).

Conclusions

This ex vivo study suggests that TNF‐α inhibitors and prednisolone are the most powerful inhibitors of proinflammatory cytokines and AMPs in HS lesional skin, which concurs with our clinical experience in patients with HS.

What's already known about this topic?

A key element of hidradenitis suppurativa (HS) is an aberrant immune response characterized by the overexpression of several proinflammatory cytokines and antimicrobial peptides in lesional skin.

Biologics targeting inflammatory cytokines have the potential to improve HS disease activity.

There is still need for efficacious drugs in the treatment of HS.

What does this study add?

We sought to quantify the anti‐inflammatory effects of currently available biologics in an ex vivo disease model.

Adalimumab, infliximab, secukinumab, ustekinumab and rituximab in addition to prednisolone significantly inhibited a selected panel of proinflammatory cytokines and antimicrobial peptides in ex vivo HS lesional skin.

Adalimumab, infliximab and prednisolone reduced the levels of a broader mix of individual cytokines than secukinumab, ustekinumab and rituximab.

What is the translational message?

The significant inhibition of important proinflammatory cytokines by tumour necrosis factor‐α inhibitors in HS correlates with their clinical efficacy.

Our ex vivo skin culture system represents an adequate model for studies in search of novel candidate drugs for the treatment of HS and to personalize the treatment in specific patients.

Linked Comment: https://doi.org/10.1111/bjd.18173.

https://www.bjdonline.com/article/

Correlation of the refined Hurley classification for hidradenitis suppurativa with patient-reported quality of life and objective disease severity assessment

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic, debilitating, heterogeneous disease requiring different treatment approaches. Recently, we refined the classic Hurley classification into a seven-stage classification in order to guide these treatment choices. This new classification subdivides Hurley stage I and II into three substages, namely mild (A), moderate (B) and severe (C) HS disease. Hurley stage III is not subcategorized and is always severe.

OBJECTIVES

To investigate the correlation between the given severity grades of Hurley I and Hurley II in the refined Hurley classification, and the patient-reported quality of life and physician-assessed objective severity score.

MATERIALS AND METHODS

In this cross-sectional study, patients with HS participating in the observational cohorts of two Dutch tertiary referral centres were included before June 2017. The patient-reported Dermatology Life Quality Index (DLQI) and physician-assessed International HS Severity Score System (IHS4) scores were compared between the refined Hurley stages.

RESULTS

In total, 433 patients were analysed. DLQI and IHS4 scores increased within Hurley stage I and II from A through C. There was a significant positive correlation of DLQI and IHS4 with increasing refined Hurley substages [refined Hurley stage I (A, B and C) to DLQI: r_s = 0·259, P < 0·001 and refined Hurley stage II (A, B and C) to DLQI: r_s = 0·185, P = 0·010; refined Hurley stage I (A, B and C) to IHS4: r_s = 0·603, P < 0·001 and refined Hurley stage II (A, B and C) to IHS4: r_s = 0·532, P < 0·001].

CONCLUSIONS

The refined Hurley classification accurately correlates with HS severity assessed by both patients and clinicians. Therefore, the refined Hurley classification is a useful tool for the quick assessment of severity in HS.

Apremilast for moderate hidradenitis suppurativa: no significant change in lesional skin inflammatory biomarkers

Background

Treatment with apremilast has recently demonstrated clinically meaningful improvement in moderate hidradenitis suppurativa (HS).

Objective

To evaluate the change in expression of inflammatory markers in lesional skin of HS patients receiving apremilast 30 mg twice daily (n = 15) for 16 weeks compared with placebo (n = 5).

Methods

At baseline, 5‐mm punch biopsies were obtained from an index lesion (HSL) and non‐lesional (HSN) skin in the same anatomical area. Subsequent HSL samples were taken as close as possible to the previously biopsied site at week 4 and week 16. After sampling, biopsies were split; one half was processed for in vivo mRNA analysis using real‐time quantitative PCR; the other half was cultured for ex vivo protein analysis using a proximity extension assay (Olink). Linear mixed effects models were calculated to compare the levels of inflammatory markers in HSL skin between apremilast and placebo over time.

Results

At baseline, 17 proteins with a fold change >2 in HSL vs. HSN skin were identified in 20 patients. The top five were IL‐17A (5), S100A12, CST5, IL‐12/23p40, CD6 (1) with fold changes ranging from 6.6 to 1638, respectively (FDR <0.044). Linear mixed effects models for 75 assays were calculated. Protein levels of S100A12 decreased during treatment in the apremilast group compared with the placebo group (p = 0.014, FDR = 0.186). None of the 14 genes exhibited significant changes in expression over time. However, an evident downward trend in relative mRNA expression of IL‐17A and IL‐17F was demonstrated in patients receiving apremilast.

Conclusion

We did not detect statistically significant changes in inflammatory markers in HSL skin of HS patients receiving apremilast compared with placebo, despite clinical improvement in the apremilast group. Nonetheless, S100A12 and IL‐17A were significantly elevated in HSL skin and showed a decrease in response to apremilast. The translational model in clinical trials involving HS clearly needs further improvement.

Hidradenitis suppurativa/acne inversa: a practical framework for treatment optimization - systematic review and recommendations from the HS ALLIANCE working group

Hidradenitis suppurativa (HS)/acne inversa is a debilitating chronic disease that remains poorly understood and difficult to manage. Clinical practice is variable, and there is a need for international, evidence‐based and easily applicable consensus on HS management. We report here the findings of a systematic literature review, which were subsequently used as a basis for the development of international consensus recommendations for the management of patients with HS. A systematic literature review was performed for each of nine clinical questions in HS (defined by an expert steering committee), covering comorbidity assessment, therapy (medical, surgical and combinations) and response to treatment. Included articles underwent data extraction and were graded according to the Oxford Centre for Evidence‐based Medicine criteria. Evidence‐based recommendations were then drafted, refined and voted upon, using a modified Delphi process. Overall, 5310 articles were screened, 171 articles were analysed, and 65 were used to derive recommendations. These articles included six randomized controlled trials plus cohort studies and case series. The highest level of evidence concerned dosing recommendations for topical clindamycin in mild disease (with systemic tetracyclines for more frequent/widespread lesions) and biologic therapy (especially adalimumab) as second‐line agents (following conventional therapy failure). Good‐quality evidence was available for the hidradenitis suppurativa clinical response (HiSCR) as a dichotomous outcome measure in inflammatory areas under treatment. Lower‐level evidence supported recommendations for topical triclosan and oral zinc in mild‐to‐moderate HS, systemic clindamycin and rifampicin in moderate HS and intravenous ertapenem in selected patients with more severe disease. Intralesional or systemic steroids may also be considered. Local surgical excision is suggested for mild‐to‐moderate HS, with wide excision for more extensive disease. Despite a paucity of good‐quality data on management decisions in HS, this systematic review has enabled the development of robust and easily applicable clinical recommendations for international physicians based on graded evidence.

Biofilm production and antibiotic susceptibility of Staphylococcus epidermidis strains from Hidradenitis Suppurativa lesions

BACKGROUND

An aberrant interaction between commensal skin bacteria and the host skin immune system is considered important in the pathogenesis of hidradenitis suppurativa (HS).

OBJECTIVE

In this study, we investigated the antibiotic susceptibility and biofilm-forming capabilities of S. epidermidis strains isolated from HS patients.

METHODS

Skin biopsies were taken from active HS lesions such as inflammatory nodules and/or sinuses and non-involved skin from 26 patients and cultured under optimal microbiological conditions for 24 h. Planktonic growth, biofilm production, antibiotic susceptibility and biofilm eradication by clindamycin, doxycycline, rifampicin and tetracycline were tested including a laboratory control strain of S. epidermidis for reference.

RESULTS

Staphylococcus epidermidis was cultured in 16 of 26 HS patients (62%). In total 27 different S. epidermidis isolates were identified; 16 (59%) from non-involved skin and 11 (41%) from HS lesions. All bacterial strains showed planktonic growth. Twenty-four of 27 (89%) isolates were strong biofilm producers in vitro. The biofilm-forming capability varied amongst the strains from non-involved skin and lesional skin. Twenty-four strains had an intermediate to resistant antibiotic susceptibility to clindamycin (89%). Rifampicin was the most effective antibiotic at inhibiting planktonic growth and at eradication of biofilm (P < 0.05).

CONCLUSION

We observed a slight increase in S. epidermidis virulence, characterized by resistance to commonly used antibiotics, increased biofilm production and resistance to biofilm eradication. In particular, the reduced sensitivity to tetracycline and clindamycin, two standard antibiotics in the treatment of HS, is alarming. Rifampicin, also important in HS treatment, showed the greatest efficacy at eradicating the biofilm at low MIC concentrations.

Current and future treatment of hidradenitis suppurativa

This scholarly review on the current and future treatment of hidradenitis suppurativa (HS) focuses on medical and surgical treatment options, while novel pipeline drugs are also discussed. Treatment goals are to limit the incidence and duration of flares, reducing inflammation and suppuration, achieving local cure after surgery and, most importantly, to improve the quality of life of patients with HS. The type of medication and/or surgery should be chosen based on the stage of the disease and the degree of inflammation. However, the lack of a simple scoring system and the lack of clear surgical outcome definitions hamper the interpretation of treatment efficacy and the comparison between different treatment strategies. The therapeutic pipeline for HS is gradually expanding, and will probably lead to a broader panel of more effective therapeutic options.

Towards global consensus on core outcomes for hidradenitis suppurativa research: an update from the HISTORIC consensus meetings I and II

BACKGROUND

A core outcomes set (COS) is an agreed minimum set of outcomes that should be measured and reported in all clinical trials for a specific condition. Hidradenitis suppurativa (HS) has no agreed-upon COS. A central aspect in the COS development process is to identify a set of candidate outcome domains from a long list of items. Our long list had been developed from patient interviews, a systematic review of the literature and a healthcare professional survey, and initial votes had been cast in two e-Delphi surveys. In this manuscript, we describe two in-person consensus meetings of Delphi participants designed to ensure an inclusive approach to generation of domains from related items.

OBJECTIVES

To consider which items from a long list of candidate items to exclude and which to cluster into outcome domains.

METHODS

The study used an international and multistakeholder approach, involving patients, dermatologists, surgeons, the pharmaceutical industry and medical regulators. The study format was a combination of formal presentations, small group work based on nominal group theory and a subsequent online confirmation survey.

RESULTS

Forty-one individuals from 13 countries and four continents participated. Nine items were excluded and there was consensus to propose seven domains: disease course, physical signs, HS-specific quality of life, satisfaction, symptoms, pain and global assessments.

CONCLUSIONS

The HISTORIC consensus meetings I and II will be followed by further e-Delphi rounds to finalize the core domain set, building on the work of the in-person consensus meetings.

Biosimilars for psoriasis: worldwide overview of regulatory guidelines, uptake and implications for dermatology clinical practice

The introduction of biological drugs for the treatment of patients with psoriasis has revolutionized treatment paradigms and enabled numerous patients to achieve disease control with an acceptable safety profile. However, the high cost of biologics limits access to these medications for the majority of patients worldwide. In recent years, the introduction of biosimilars for inflammatory diseases has become a fast evolving field. The future use of biosimilars offers the potential for decreased cost and increased access to biologics for patients with psoriasis. For approval of biosimilars, different regulatory agencies use highly variable methods for definition, production, approval, marketing and postmarketing surveillance. Due to potential interchangeability between biologics and biosimilars, traceability and pharmacovigilance are required to collect accurate data about adverse events in patients with psoriasis; spontaneous reporting, registries and use of 'big data' should facilitate this process on a global basis. The current article describes biosimilar regulatory guidelines and examples of biosimilar uptake in clinical practice in several countries around the world. As it is apparent that biological therapy treatment decisions may become more physician independent, the International Psoriasis Council recommends that dermatologists should take an active role in the development of biosimilar prescribing policies with their respective healthcare settings and government agencies.

Development and validation of the International Hidradenitis Suppurativa Severity Score System (IHS4), a novel dynamic scoring system to assess HS severity

BACKGROUND

A validated tool for the dynamic severity assessment of hidradenitis suppurativa/acne inversa (HS) is lacking.

OBJECTIVES

To develop and validate a novel dynamic scoring system to assess the severity of HS.

METHODS

A Delphi voting procedure was conducted among the members of the European Hidradenitis Suppurativa Foundation (EHSF) to achieve consensus towards an initial HS Severity Score System (HS4). Strengths and weaknesses of HS4 were examined by a multicentre prospective study. Multivariate logistic regression, discriminant analysis and receiver operating characteristic curves, as well as examination for correlation (Spearman's rho) and agreement (Cohen's kappa) with existing scores, were engaged to recognize the variables for a new International HS4 (IHS4) that was established by a second Delphi round.

RESULTS

Consensus HS4 was based on number of skin lesions, number of skin areas involved and Dermatology Life Quality Index (DLQI), and was evaluated by a sample of 236 patients from 11 centres. Subsequently, a multivariate regression model calculated adjusted odds ratios for several clinical signs. Nodules, abscesses and draining tunnels resulted as the scoring variables. Three candidate scores were presented to the second Delphi round. The resulting IHS4 score is arrived at by the number of nodules (multiplied by 1) plus the number of abscesses (multiplied by 2) plus the number of draining tunnels (multiplied by 4). A total score of 3 or less signifies mild, 4-10 signifies moderate and 11 or higher signifies severe disease. Cohen's kappa was fair (κ = 0·32) compared with Hurley classification, and moderate (κ = 0·49) compared with Expert Opinion. Correlation was good (ρ > 0·6) with Hurley classification, Expert Opinion, Physician's Global Assessment and Modified Sartorius score, and moderate for DLQI (ρ = 0·36).

CONCLUSIONS

The novel IHS4 is a validated tool to dynamically assess HS severity and can be used both in real-life and the clinical trials setting.

Sexual health and quality of life are impaired in hidradenitis suppurativa: a multicentre cross-sectional study

BACKGROUND

Hidradenitis suppurativa (HS) has a major impact on patients' quality of life (QoL). Although it has commonly been assumed that HS impairs sexual health, only a single case-control study has been performed on sexual functioning in a small group of patients with HS.

OBJECTIVES

To investigate the QoL with a particular focus on sexual health in a substantial population of patients with HS.

METHODS

In total 916 patients with HS received an invitation to participate in this multicentre cross-sectional survey.

RESULTS

Three hundred patients completed the questionnaires. This study showed a diminished QoL and sexual health in patients with HS (Female Sexual Function Index: 21·6 ± 9·6, International Index of Erectile Function: 49·7 ± 20·7, Arizona Sexual Experience Scale: 16·7 ± 5·3, Dermatology Life Quality Index: 12·5 ± 7·5). Sexual health was associated with QoL in women but not in men. Female sex and late onset of HS were associated with poor sexual function. Impairment of QoL was associated with anogenital involvement, early onset of HS, disease severity and disease activity.

CONCLUSIONS

HS is associated with impaired sexual health and QoL. Physicians should not hesitate to ask patients with HS about their sexual function and, when needed, offer them psychological support.

Non-invasive anaesthetic methods for dermatological laser procedures: a systematic review

Pain is a common side-effect of dermatological laser procedures. Non-invasive anaesthetic drugs and anaesthetic procedures can be used to provide pain relief and increase patient satisfaction and treatment efficacy. However, it remains unclear which method provides the best pain relief. The objective of this systematic review was therefore to assess the efficacy and safety of non-invasive anaesthetic methods during dermatological laser procedures. A systematic literature search was conducted. Randomized and non-randomized controlled clinical trials (RCTs and CCTs) were included. Two authors independently assessed study eligibility, extracted data and assessed the risk of bias. The quality of evidence was rated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Twenty RCTs and 12 CCTs were included, involving nine different laser indications: hair removal (n = 9), resurfacing/rejuvenation (n = 5), port wine stains (n = 8), leg telangiectasia (n = 3), facial telangiectasia (n = 2), tattoo removal (n = 2), naevus of Ota (n = 1), solar lentigines (n = 1) and HPV lesions (n = 1). The non-invasive anaesthetic methods (i.e. topical anaesthetic drugs, skin cooling, and pneumatic skin flattening [PSF]), types of lasers, laser settings, application time, and types of pain scales varied widely among the included studies. All of the studies had an unclear or high risk of bias, and the overall quality of evidence was rated as low. In general, active non-invasive anaesthetic methods seemed to provide favourable results compared to placebo or no anaesthesia, and topical anaesthetic drugs and PSF seemed to result in a better pain reduction than skin cooling. However, the current evidence is insufficient to provide recommendations for daily clinical practice. There is a need for more high-quality (head-to-head) RCTs. Future studies should also evaluate sex differences in pain perception, have uniformity with regard to validated pain measurement scales and address clinically significant differences in pain reduction besides statistically significant differences.

Comparison of lidocaine/tetracaine cream and lidocaine/prilocaine cream for local anaesthesia during laser treatment of acne keloidalis nuchae and tattoo removal: results of two randomized controlled trials

BACKGROUND

Pain is a common adverse effect of dermatological laser procedures. Currently, no standard topical anaesthetic cream exists for deeper dermal laser procedures.

OBJECTIVES

To compare the efficacy of lidocaine/tetracaine cream and lidocaine/prilocaine cream in reducing self-reported pain during deeper dermal laser treatment of acne keloidalis nuchae (AKN) and tattoos.

METHODS

We conducted two randomized, double-blind, controlled clinical trials with intrapatient, split-lesion designs: study A included patients with AKN (n = 15); study B included patients with black tattoos (n = 15). The primary end point was the patients' self-reported pain on a 10-cm visual analogue scale (VAS). Secondary objectives were the percentage of patients with adequate pain relief, willingness to pay €25 for the cream that provided the best pain relief and safety of the creams.

RESULTS

In both studies, VAS scores were lower for lidocaine/prilocaine cream, with a mean VAS difference in study A of 1·9 [95% confidence interval (CI) 1·0-2·8] and in study B of 0·6 (95% CI -0·7 to 1·9). In study A, adequate pain relief was achieved in 13% (n = 2) with lidocaine/tetracaine cream vs. 73% (n = 11) with lidocaine/prilocaine cream (P = 0·004), and in study B in 53% (n = 8) vs. 80% (n = 12), respectively (P = 0·289). In study A, 47% (n = 7) were willing to pay an additional €25 vs. 73% (n = 11) in study B. No serious adverse events occurred.

CONCLUSIONS

Lidocaine/prilocaine cream under plastic occlusion is the preferred topical anaesthetic during painful laser procedures targeting dermal chromophores.

An Update on Medical Treatment Options for Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by recurrent inflammatory nodules mostly located in the armpits and groin. Over the years multiple treatments for HS have been proposed; however, to date a cure is still lacking. In this update we provide an overview of most drug treatments reported on for HS, where possible with their mode of action and side effects. In mild cases, clindamycin lotion or resorcinol cream have proven effective. Tetracyclines are a first-line systemic option in more widespread or severe cases, followed by the combination of clindamycin and rifampicin. However, the recurrence rate is high after discontinuation of clindamycin plus rifampicin combination therapy. Long-term treatment with retinoids, especially acitretin is feasible, although teratogenicity has to be taken into account in females of reproductive age. Multiple anti-inflammatory drugs have been suggested for HS, such as dapsone, fumarates or cyclosporine. However, their effectiveness in HS is based on small case series with varying results. If most common treatments have failed, biologics (e.g., infliximab or adalimumab) are the next step. Although not addressed in this review, surgical interventions are often needed to achieve remission.

Lentigo maligna - anatomic location as a potential risk factor for recurrences after non-surgical treatment

Background

A higher incidence of lentigo maligna (LM) recurrences on the nose was previously observed in our cohort after non‐surgical treatment.

Objectives

To determine histological parameters that might be related to the previously observed higher incidence of LM recurrences on the nose after non‐surgical treatment.

Methods

We randomly selected 22 surgical specimens of LM on the nose and 22 on the cheek. Histopathological analysis was performed on haematoxylin and eosin stained and microphthalmia transcription factor immunohistochemically stained slides. The number of pilosebaceous units (PSU) per mm, maximum depth of atypical melanocytes along the skin appendages and maximum depth of the PSU itself were determined.

Results

The nose had a significantly higher density of PSU than the cheek. The atypical melanocytes extended deeper along the PSU on the nose with a mean (SD) depth of 1.29 mm (0.48) vs. a mean depth of 0.72 mm (0.30) on the cheek (P < 0.001). The maximum depth of the PSU on the nose was greater than on the cheek, mean (SD) depth of 2.28 mm (0.41) vs. 1.65 mm (0.82) (P = 0.003).

Conclusions

The higher recurrence risk of LM on the nose after non‐surgical treatment that we previously observed in our cohort is most likely based on a higher density of atypical melanocytes and also their deeper extension into the follicles. These results shed more light on our previous findings and learn that anatomical location is relevant for the risk of recurrence of LM after non‐surgical treatment.

European S1 guideline for the treatment of hidradenitis suppurativa/acne inversa

Hidradenitis suppurativa/acne inversa (HS) is a chronic, inflammatory, recurrent, debilitating skin disease of the hair follicle that usually presents after puberty with painful, deep-seated, inflamed lesions in the apocrine gland-bearing areas of the body, most commonly the axillae, inguinal and anogenital regions. A mean disease incidence of 6.0 per 100,000 person-years and an average prevalence of 1% has been reported in Europe. HS has the highest impact on patients' quality of life among all assessed dermatological diseases. HS is associated with a variety of concomitant and secondary diseases, such as obesity, metabolic syndrome, inflammatory bowel disease, e.g. Crohn's disease, spondyloarthropathy, follicular occlusion syndrome and other hyperergic diseases. The central pathogenic event in HS is believed to be the occlusion of the upper part of the hair follicle leading to a perifollicular lympho-histiocytic inflammation. A highly significant association between the prevalence of HS and current smoking (Odds ratio 12.55) and overweight (Odds ratio 1.1 for each body mass index unit) has been documented. The European S1 HS guideline suggests that the disease should be treated based on its individual subjective impact and objective severity. Locally recurring lesions can be treated by classical surgery or LASER techniques, whereas medical treatment either as monotherapy or in combination with radical surgery is more appropriate for widely spread lesions. Medical therapy may include antibiotics (clindamycin plus rifampicine, tetracyclines), acitretin and biologics (adalimumab, infliximab). A Hurley severity grade-relevant treatment of HS is recommended by the expert group following a treatment algorithm. Adjuvant measurements, such as pain management, treatment of superinfections, weight loss and tobacco abstinence have to be considered.

Summary of the Dutch S3-guidelines on the treatment of psoriasis 2011. Dutch Society of Dermatology and Venereology

This document provides a summary of the Dutch S3-guidelines on the treatment of psoriasis. These guidelines were finalized in December 2011 and contain unique chapters on the treatment of psoriasis of the face and flexures, childhood psoriasis as well as the patient's perspective on treatment. They also cover the topical treatment of psoriasis, photo(chemo)therapy, conventional systemic therapy and biological therapy.

Failure of anti-interleukin-1 therapy in severe hidradenitis suppurativa: a case report

Hidradenitis suppurativa (HS) is an inflammatory, debilitating skin disease of follicular origin, characterized by painful deep-seated, inflamed lesions in mainly the inverse areas of the body. HS is notoriously difficult to treat and especially severe disease is often resistant to therapy. New therapeutic options are therefore highly needed. Elevated levels of IL-1 have been demonstrated in HS lesions. Here we report for the first time on the sequential treatment with anakinra (an IL-1 receptor antagonist) and golimumab (a TNF-α-neutralizing antibody) of a patient with severe HS and with comorbid psoriatic arthritis. Although adalimumab and golimumab were efficacious in improving arthritis complaints, both failed in improving the severe HS of our patient. Eventually the patient underwent radical excision of the inflammatory lesions and fistulas.

Can animal skin diseases or current transgenic mice serve as a model for hidradenitis suppurativa?

The pathogenesis of hidradenitis suppurativa (HS) is still enigmatic, and a valid animal model for HS is currently not available. The recent discovery of γ-secretase mutations in a subpopulation of patients with HS suggested γ-secretase transgenic mice as a model for HS pathogenesis. However, the discrepancies between human HS and these mice are daunting. We critically review cases of animal HS and transgenic γ-secretase mouse models for HS and discuss the criteria which should be met for a representative pathogenic model.

Adalimumab (antitumour necrosis factor-α) treatment of hidradenitis suppurativa ameliorates skin inflammation: an in situ and ex vivo study

BACKGROUND

Hidradenitis suppurativa (HS) is a difficult-to-manage disease. Randomized controlled trials with antitumour necrosis factor (TNF)-α biologics have been conducted and in most studies disease activity was reduced. However, the mechanism of action in HS skin is so far unknown.

OBJECTIVES

To assess whether anti-TNF-α treatment affects in situ cytokine production and frequency of inflammatory cell populations in HS lesional skin.

METHODS

Nine patients with HS, participating in a larger placebo-controlled, double-blind phase IIb clinical trial on the efficacy and safety of adalimumab in patients with moderate to severe HS (M10-467), were randomized and treated for 16weeks. In a mechanism-of-action substudy, biopsies were obtained at fixed time points pre- and post-treatment. One part of the biopsy was cultured for 24h for cytokine release in the culture medium, while another part was used for in situ analysis.

RESULTS

Secretion of cytokines, including interleukin (IL)-1β, CXCL9 [monokine induced by interferon-γ (MIG)], IL-10, IL-11, B-lymphocyte chemoattractant (BLC) and IL-17A, was significantly elevated in HS. Adalimumab treatment was associated with decreased production of cytokines in HS skin, especially IL-1β, CXCL9 (MIG) and BLC. Treatment significantly reduced the number of CD11c+,CD14+ and CD68+ cells in HS lesional skin. The numbers of CD3+ and CD4+ T cells, and CD20+ and CD138+ B cells were also reduced by adalimumab treatment.

CONCLUSIONS

Adalimumab treatment inhibits important cytokines and inflammatory cell numbers in lesional HS skin, especially levels of IL-1β and numbers of inflammatory CD11c+ dendritic cells.

Alterations in leucocyte subsets and histomorphology in normal-appearing perilesional skin and early and chronic hidradenitis suppurativa lesions

BACKGROUND

Current insight into the histopathological course of events during disease progression in hidradenitis suppurativa (HS) is fragmentary.

OBJECTIVES

To identify histological alterations and leucocyte subsets in normal-appearing perilesional skin, and early and chronic HS lesions.

METHODS

In this observational study we examined eight perilesional skin samples, and six early and 10 chronic prototypic HS lesions, as well as skin samples from four healthy donors using in situ immunostaining.

RESULTS

Perilesional skin showed mild psoriasiform hyperplasia and follicular plugging as well as a low-grade influx of tryptase-positive mast cells, CD3+ T cells, CD138+ plasma cells and factor XIIIa+ dendritic cells. In early HS lesions, neutrophilic abscess formation and influx of mainly macrophages, monocytes and dendritic cells predominated. In chronic disease, the infiltrate expanded with markedly increased frequencies of CD20+ and CD79a+ B cells and CD138+ plasma cells. As in early lesions, free keratin fibres were detected in the dermis and within giant cells. Single detached keratinocytes and strands of follicular epithelium were observed in the dermis, the latter frequently expressing Ki67, indicative of active proliferation.

CONCLUSIONS

Psoriasiform hyperplasia, follicular plugging and low-grade leucocytic infiltration are already present in normal-appearing perilesional skin. Keratin fibres in the dermis are associated with clinical disease. Early lesions are characterized by neutrophilic abscess formation and influx of mainly histiocytes, and chronic lesions mainly by expansion of B cells and plasma cells in 'pseudo' follicles. Proliferating strands of follicular epithelium may initiate fistula formation. Mast cells are increased in all stages of HS including perilesional skin.

The anti-inflammatory drug colchicine lacks efficacy in hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease. Since current treatments are unsatisfactory for many patients, there is a high need for effective drugs for this debilitating disease. Recent pathogenic insights suggest inflammasome activation and IL-1β production are important in HS. Colchicine is efficacious in the IL-1β- and inflammasome-mediated diseases gout, familial Mediterranean fever and Behçet's disease, and therefore a potentially effective drug in HS.

OBJECTIVE

To investigate the efficacy of colchicine in HS.

METHODS

In an open prospective pilot study, 8 HS patients were treated with the accepted gout maintenance regimen of 0.5 mg colchicine b.i.d. orally up to 4 months. Efficacy was assessed by a physician global assessment.

RESULTS

Colchicine treatment did not result in a clinically relevant improvement of disease severity. Three patients experienced nausea and diarrhea as known side effects.

CONCLUSION

Colchicine in the used dose regimen does not ameliorate HS severity.

Pathogenesis and pharmacotherapy of Hidradenitis suppurativa

The focus of this review is to discuss the pathogenesis and the pharmacotherapy of Hidradenitis suppurativa (HS). HS is a distressing chronic skin disorder characterized by abscesses, boils, fistulas and scarring, generally affecting the groins, anogenital area and axillae. It is a common disease with an estimated prevalence of 1%. The etiology is unknown. HS was thought to be a disease of the apocrine sweat glands, but histological findings indicate that HS is a disease arising from the hair follicles. Several pathogenic factors seem important including genetic predisposition, smoking, obesity and an aberrant immune response to commensal flora. The management of HS is tremendously challenging because effective therapies are lacking. Nevertheless, HS has been treated with topical and systemic antibiotics, retinoids and immunosuppressive drugs such as anti-TNF-α biologics with partial success. In this review we will also discuss a potential new therapy for HS with the anti-psoriases agent acitretin.

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

BACKGROUND

The pathogenesis of hidradenitis suppurativa (HS) is largely unknown and the disease is difficult to treat. Patients are in high need of an effective treatment. Although it is not known whether the levels of tumour necrosis factor (TNF)-α are aberrant in HS skin, anti-TNF-α biologics are used, with variable clinical efficacy.

OBJECTIVES

To determine the cytokine profile in lesional and perilesional HS skin.

METHODS

We cultured 20 lesional and 10 normal-appearing perilesional HS skin samples, seven psoriasis and six healthy control skin samples in a transwell culture system. Two distinct cytokine bead arrays were used to measure the spectrum of inflammatory cytokines in the culture supernatant. Results from HS skin samples were compared with those of healthy and psoriasis skin.

RESULTS

The proinflammatory cytokines interleukin (IL)-1β and TNF-α as well as the anti-inflammatory cytokine IL-10 were significantly elevated in HS skin. Elevated levels of these cytokines were also found in perilesional HS skin. Fold increases relative to control skin of IL-1β, TNF-α and IL-10 in HS were 31, 5 and 34, compared with psoriasis: 4, 1 and 2, respectively. Levels of all three cytokines showed a trend towards a positive correlation with disease severity. IL-2, IL-4, IL-5 and interferon-γ were hardly detectable in HS or healthy control skin.

CONCLUSIONS

This study shows for the first time that IL-1β, TNF-α and IL-10 levels are elevated in HS skin. These data provide a rationale for therapies with biologics targeting cytokines such as TNF-α and IL-1.

Narrowband ultraviolet B inhibits innate cytosolic double-stranded RNA receptors in psoriatic skin and keratinocytes

BACKGROUND

The mode of action of narrowband ultraviolet B (NB-UVB) therapy in clearing psoriasis is incompletely understood, and in vivo studies at the molecular level in patients undergoing NB-UVB therapy are limited. We previously demonstrated increased expression and activity of double-stranded RNA (dsRNA) receptors in psoriasis lesions, and suggested that this enhanced innate signalling contributed to the maintenance of psoriatic inflammation.

OBJECTIVES

We investigated whether NB-UVB affects dsRNA receptor expression and function in vivo as well as in vitro.

METHODS

Skin samples of patients with psoriasis undergoing NB-UVB treatment were analysed for epidermal messenger RNA (mRNA) expression of the various dsRNA receptors by microarray and quantitative reverse transcription-polymerase chain reaction. Primary human keratinocytes were irradiated with NB-UVB and stimulated with interferon (IFN)-α or IFN-γ, critical cytokines in psoriasis. The dsRNA analogue polyriboinosinic-polyribocytidylic acid was used to assess the functional responsiveness of the cells to dsRNA.

RESULTS

NB-UVB therapy of patients with psoriasis resulted in a significantly reduced mRNA expression of the activating dsRNA receptors MDA5 (IFIH1) and RIG-I (DDX58). On the other hand, expression of LGP2 (DHX58), toll-like receptor 3 (TLR3) and PKR (EIF2AK2) was not affected. In vitro, NB-UVB irradiation completely blocked the upregulation of four of the dsRNA receptors in primary human keratinocytes stimulated with IFN-α or IFN-γ, resulting in an attenuated inflammatory response to dsRNA.

CONCLUSIONS

Our results show that NB-UVB irradiation inhibits the local innate inflammatory response to dsRNA, and suggest a novel mechanism of action of NB-UVB phototherapy in psoriasis.

Hidradenitis suppurativa and inflammatory bowel disease: are they associated? Results of a pilot study

Background The co-occurrence of hidradenitis suppurativa (HS) and Crohn disease (CD) published in a few case reports resulted in the wide acceptance of an association between these two diseases. However, the combined prevalence of these diseases is currently unknown; furthermore, it is unknown whether this co-occurrence also applies for ulcerative colitis (UC). Objectives To estimate the prevalence of HS in patients with inflammatory bowel disease (IBD) living in the Southwest of the Netherlands. Methods During an IBD patient information meeting, randomly, 158 patients with IBD were interviewed about recurrent painful boils in the axillae and/or groin and were shown illustrative clinical pictures of the appearance of HS. Results Of the 158 patients interviewed, 102 (65%) had CD and 56 (35%) had UC. Twenty-five people (16%) responded that they had had or still experienced painful boils in the axillae and/or groin, of whom 17 were patients with CD (17%) and eight had UC (14%). Conclusions This pilot study shows for the first time that HS occurs in patients with CD or UC. More prospective studies are warranted to establish the association between HS and IBD and its underlying pathogenesis.