The prevalence of hidradenitis suppurativa is shown by the Secure Anonymised Information Linkage ( SAIL ) Databank to be one per cent of the population of Wales

Global consensus process to establish a core dataset for hidradenitis suppurativa registries

BACKGROUND

Several registries for hidradenitis suppurativa (HS) already exist in Europe and the USA. There is currently no global consensus on a core dataset (CDS) for these registries. Creating a global HS registry is challenging, owing to logistical and regulatory constraints, which could limit opportunities for global collaboration as a result of differences in the dataset collected. The solution is to encourage all HS registries to collect the same CDS of information, allowing registries to collaborate.

OBJECTIVES

To establish a core set of items to be collected by all HS registries globally. The core set will cover demographic details, comorbidities, clinical examination findings, patient-reported outcome measures and treatments.

METHODS

Beginning in September 2022, 20 participants - including both clinicians with expertise in HS and patient advocates - from eight countries across three continents participated in a Delphi process consisting of four rounds of voting, with all participants completing each round. A list of potential items for inclusion in the core set was generated from the relevant published literature, including systematic reviews of comorbidities in HS, clinical and examination findings, and epidemiology. For disease severity and progression items, the Hidradenitis SuppuraTiva Core outcome set International Collaboration (HiSTORIC) core set and other relevant instruments were considered for inclusion. This resulted in 47 initial items. Participants were invited to suggest additional items to include during the first round. Anonymous feedback was provided to inform each subsequent round of voting to encourage consensus.

RESULTS

The eDelphi process established a CDS of 48 items recommended for inclusion in all HS registries globally.

CONCLUSIONS

The routine adoption of this CDS in current and future HS registries should allow registries in different parts of the world to collaborate, enabling research requiring large numbers of participants.

The Role of Hormones in Hidradenitis Suppurativa: A Systematic Review

Hidradenitis suppurativa (HS) is a chronic inflammatory disease manifesting in inverse body regions. In a systematic review, the role of hormones in HS will be presented to better understand the pathomechanisms of HS. The review is based on the PRISMA criteria. Systematic research was carried out using keywords. Subsequently, the data were analyzed based on the clinical response and other relevant information. The main focus of our systematic review was on HS manifestation, exacerbation, sex hormones, antiandrogen therapy, thyroid function, polycystic ovary syndrome, insulin resistance, and adipokines. In HS, there appears to be a dysregulated adipokine release that is shifted towards pro-inflammatory adipokines. Insulin resistance is significantly more common in HS than in healthy patients regardless of BMI, age, and gender. Insulin resistance in HS patients leads to further cardiovascular disease. The mechanism of insulin resistance and role of adipokines should be investigated in future studies to better provide the pathomechanisms of HS. The role of androgens seems to be important in a certain subgroup of female patients. Anti-androgenic therapy can be useful and helpful in some patients. However, further studies are needed to better understand the hormonal relationship in HS.

The prevalence of hidradenitis suppurativa outside the hospital setting: the impact of the undiagnosed

Linked Article: Prens et al. Br J Dermatol 2022; 186:814–822.

New Insights in Hidradenitis Suppurativa from a Population-based Dutch Cohort: Prevalence, Smoking Behaviour, Socioeconomic Status and Comorbidities

Background

Hidradenitis suppurativa (HS) is a chronic autoinflammatory skin condition and is associated with several comorbidities. Previous studies report variable prevalence rates of HS, depending on the methodology. However, the exact prevalence remains unknown.

Objectives

To estimate the prevalence of HS in a large population‐based cohort in the Northern Netherlands, and to compare patients with HS to the general population, investigate characteristics and identify potential associated comorbidities.

Methods

Data were collected through a cross‐sectional survey‐based study within the Lifelines Cohort Study (n = 167 729), based on the general population located in the Northern Netherlands. A digital self‐reported questionnaire was developed consisting of validated questions for determining HS.

Results

Among 56 084 respondents, the overall prevalence of HS was 2.1% [95% confidence interval (CI) 2.0–2.2]. The respondents with HS had lower socioeconomic status than the controls (P < 0.001) and more frequently currently smoked (P < 0.001). Several new significant associations in patients with HS were revealed, such as fibromyalgia (OR 2.26, 95% CI 1.64–3.11), irritable bowel syndrome (OR 1.63, 95% CI 1.18–2.26), chronic fatigue syndrome (OR 1.72, 95% CI 1.06–2.78) and migraine (OR 1.48, 95% CI 1.11–1.96). Fibromyalgia and chronic fatigue syndrome remained significantly associated with HS in the multivariate analysis after adjusting for age, sex, body mass index, smoking status and socioeconomic status.

Conclusions

Our study showed a higher prevalence of HS in the Northern Netherlands compared with the overall estimated prevalence of 1% and identified several new associated comorbidities.

Incidence and remission rates of self-reported hidradenitis suppurativa - A prospective cohort study conducted in Danish blood donors

BACKGROUND

A large discrepancy between physician-diagnosed and self-reported Hidradenitis suppurativa (HS) exists. Knowledge regarding incidence and remission rates of self-reported HS is missing, but may help bridge the gap in understanding between these two phenotypes.

OBJECTIVES

To determine the incidence and remission rates of self-reported HS, and to what degree these are affected by sex, smoking and BMI.

METHODS

A prospective cohort of 23 930 Danish blood donors. Information on self-reported HS, symptom-localisation, sex, age, BMI and smoking status was collected at baseline and study termination. Self-reported HS fulfilled clinical obligatory diagnostic criteria. Cox proportional hazards regression analyses were conducted for both incidence and remission rates providing a hazard ratio (HR) of risk for each variable in the regression.

RESULTS

Incidence rate of self-reported HS was 10.8/1000 person-years (95% confidence interval (CI): 9.9-11.7), decreasing as a function of numbers of areas affected. Female BMI points above 25 (HR = 1.11, 95% CI: 1.09-1.13), male BMI points above 25 (HR = 1.07, 95% CI: 1.04-1.11), active smoking (HR = 1.72, 95% CI: 1.15-2.57), male sex (HR = 0.55, 95% CI: 0.45-0.67) and years of age above 25 (HR = 0.97, 95% CI: 0.96-0.97) were all statistically associated with the development of self-reported HS. Remission rate of self-reported HS was 256.7/1000 person-years (95% CI: 223.9-292.6), decreasing as a function of numbers of affected areas. Symptoms in ≥3 areas (HR = 0.54, 95% CI: 0.34-0.85), active smoking (HR = 0.49, 95% CI: 0.32-0.76) and female weight loss (every percentage drop in BMI: HR = 1.07, 95% CI: 1.05-1.11) all significantly affected the remission rate.

CONCLUSIONS

Both incidence and remission rates of self-reported HS are high, indicating that many with self-reported HS are unlikely to be diagnosed, as they to a higher degree experience mild transient HS symptoms.

Primary care management of hidradenitis suppurativa: a cross-sectional survey of UK GPs

Background

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that causes painful discharging nodules and skin tunnels. HS has associations with several systemic diseases, including cardiovascular disease (CVD), anxiety, and depression. High levels of chronic morbidity suggest an important role for primary care. However, little evidence exists regarding current management of HS and its comorbidities in UK general practice.

Aim

To describe current practice among UK GPs in treating and referring people with HS.

Design & setting

A web-based survey was circulated to UK Primary Care Dermatology Society (PCDS) members and GPs in Forth Valley, Scotland.

Method

Survey responses were analysed with descriptive statistics.

Results

A total of 134 UK GPs completed the survey. Seventy per cent (n = 94) saw at least one patient with HS in the previous month. Ninety-four per cent (n = 125/133) reported confidence in diagnosis, and 89% (n = 120/134) in initial treatment of HS. Most GPs initiated topical treatments and extended courses of oral antibiotic for HS, and many gave advice on adverse lifestyle factors. A minority provided analgesia, or screening for CVD risk factors, and depression. Most GPs referred to dermatology if secondary care input was required, with few referrals to specialised multidisciplinary services.

Conclusion

GPs regularly diagnose and manage uncomplicated HS, but screening for important comorbidities associated with HS is not common practice.

Evidence of gene-gene interaction in Hidradenitis suppurativa - A nationwide register study of Danish twins

BACKGROUND

Hidradenitis suppurativa (HS) is a recurrent inflammatory skin disease that, apart from rare causative loss-of-function mutations, has a widely unknown genetic aetiology. Our objective was to estimate the relative importance of genetic and environmental factors underlying HS susceptibility.

METHODS

Through the Danish Twin Registry and the Danish National Patient Registry we joined information on zygosity with that of HS status. HS cases were identified by International Code of Diseases 8 (705.91) and 10 (L73.2). Heritability was assessed by the classic biometric model and the possibility of gene-gene interaction through the multi-locus modeling approach.

RESULTS

Amongst 100,044 registered twins, we found 170 twins (from 163 pairs) diagnosed with HS. The seven concordant pairs were all monozygotic, and monozygotic twins had a casewise concordance rate of 28% (95% CI: 7%; 49%), corresponding to a familial risk of 73 (95% CI 13; 133) times that of the background population. The biometrical modelling suggested a heritability of 0.80 (95% CI 0.67; 0.93), and the multilocus index estimate was 230 (95% CI: 60; 400). This is highly indicative of gene-gene interactions, with the possibility of up to six interacting loci.

CONCLUSION

This twin study is substantially larger, and employs a more valid phenotype than prior studies. Genetics account for the majority of the HS susceptibility, and HS is most likely caused by gene-gene interactions rather than monogenetic mutations or solely additive genetic factors. New approaches aimed at assessing potential interactions at a SNP-SNP level should be implemented in future HS genome-wide association studies.

Family physicians' awareness and general knowledge of hidradenitis suppurativa: A survey research

RATIONALE, AIMS, AND OBJECTIVE

Medical consultations of family physicians play a key role in early diagnosis and proper management of hidradenitis suppurativa (HS). This study aimed to investigate family physicians' disease awareness, general attitudes, and knowledge of HS.

MATERIAL-METHODS

This cross-sectional descriptive study was conducted with 211 family physicians and residents through a web-based survey. The questionnaire consisted of 25 questions about the demographic characteristics of the participants as well as their awareness and general knowledge of HS.

RESULTS

While 90% of physicians know that the diagnosis of HS is made clinically without any need for a laboratory examination, only 23.7% of them felt confident performing such a diagnosis. About 63% of participants defined HS as an infectious disease of the apocrine glands, contradictive to the real pathophysiology. About 21% of them had not been medically trained in HS, and 3% of them even had never heard the name of HS. Only 33% were aware of the role of biological agents. Most of the family physicians (57.4%) were willing to participate in postgraduate education programmes about HS.

CONCLUSION

The family physicians' awareness of HS is limited. Increased practice in medical education and postgraduate education programmes may help increase the knowledge of family physicians.

The epidemiology of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease defined clinically by multiple, painful inflammatory lesions occurring predominantly in flexural sites. Onset is typically soon after puberty; however, it remains unknown whether the menopause induces remission. In North American and European patients with HS the female-to-male ratio is approximately 3 : 1 but the ratio is 1 : 2 in South Korean patients. It may be that some elements of HS epidemiology cannot be generalized across all populations. Elements of HS epidemiology in the USA and Europe are well established, including strong associations with obesity and smoking, which may increase disease severity. There are associations between HS and other cardiovascular disease (CVD) risk factors, including type 2 diabetes and metabolic syndrome. People with HS have double the risk of death from CVD compared with those without HS and 1·5 times the risk compared with patients with psoriasis. Depression and anxiety are associated with HS and completed suicide rates in those with HS are more than double the rates in controls. Associations exist between HS and other chronic inflammatory conditions, particularly inflammatory bowel disease and inflammatory arthritis. Case-control studies demonstrate associations with pilonidal sinus, polycystic ovary syndrome, Down syndrome, obstructive sleep apnoea and pyoderma gangrenosum. Population-based studies using routinely collected healthcare data from the USA estimate a prevalence of 0·1%, suggesting HS is relatively uncommon. European studies include undiagnosed patients and typically estimate prevalence of 1% or more, suggesting a common condition. Resolving the controversy surrounding a greater than 10-fold difference in HS prevalence estimates remains a high priority.