Prevalence and comorbidities associated with hidradenitis suppurativa in Korea: a nationwide population-based study

Skin manifestations in spondyloarthritis

Spondyloarthritides (SpA) like psoriatic arthritis, axial spondyloarthritis/ankylosing spondylitis, reactive arthritis and inflammatory bowel disease (IBD)-associated SpA can present with characteristic skin manifestations. These SpA-associated skin disorders may precede joint involvement, reflect a loss of efficacy of a current systemic treatment or can even be treatment associated. Cutaneous manifestations in SpA not only add additional morbidity with physical impact but also impose a psychosocial burden on affected patients. Psoriasis (PsO) - the main skin disease in SpA - has a variety of clinical presentations, including plaque-type PsO, inverse PsO, guttate PsO, erythrodermic PsO, nail PsO and pustular types. SpA associated with IBD presents with neutrophilic and granulomatous skin disorders, including pyoderma gangrenosum, hidradenitis suppurativa and cutaneous Crohn's disease. Reactive arthritides has a favourable prognosis and may feature keratoderma blenorrhagicum or balanitis circinatum as typical skin manifestations. Immunologically, SpA-associated skin diseases share interleukin (IL)-17 and IL-23 dysregulation but show distinctive genetic and immunological profiles. Therefore, they vary in their treatment responses to targeted therapies with biologicals or small molecules. In this review, we highlight the clinical presentation of skin manifestations in SpA and discuss therapeutic approaches in this interdisciplinary field.

Hidradenitis suppurativa is associated with hypothyroidism and hyperthyroidism: a large-scale population-based study

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory disease involving the skin bearing apocrine glands. There are numerous comorbidities and associated diseases among patients with HS. The association of HS and thyroid abnormalities is equivocal. We aimed to explore whether HS is associated with thyroid disorders.

METHODS

In this cross-sectional large-scale population-based study in Israel, patients with a validated diagnosis of HS were matched at a proportion of 1:5 with age- and gender-matched healthy controls without HS. A cross-checking for HS diagnosis by International Classification of Diseases, ninth revision (ICD-9) coding, and hyperthyroidism and hypothyroidism by ICD-9 coding was performed. Demographic and exposure covariates were identified. Univariate and multivariate logistic regressions were utilized to establish the association of HS with thyroid disorders.

RESULTS

Study participants included 4,191 HS patients and 20,941 controls. The average age of patients was 39.7 years old, and 61.8% were female. 53.4% of HS patients and 13.5% of controls (P < 0.001) were smokers. Odds ratios (ORs) for hypothyroidism and hyperthyroidism in HS were 2.91 (95% confidence interval [CI] 2.48-3.40) and 2.25 (95% CI 1.55-3.28), respectively (P < 0.001 for both). While the association of HS with hypothyroidism was maintained across genders and all age groups, and remained positive after controlling for smoking status, the association with hyperthyroidism remained positive only among females, middle-aged patients, and nonsmokers.

CONCLUSION

HS is independently associated with hypothyroidism. The association of HS with hyperthyroidism held significance only in limited subgroups. Smoking status is a major modifier, mainly in the association of HS with hyperthyroidism.

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.

Hidradenitis suppurativa in pediatric patients

Interest in and research on hidradenitis suppurativa (HS) have increased during the past decade, resulting in expanded knowledge about associated comorbidities and treatment efficacy. Knowledge about pediatric-onset HS is still limited, based on case studies, small case series, and extrapolation from adult studies. With increasing prevalence of childhood obesity, decreasing pubertal age, and increasing awareness of HS, physicians may start encountering younger HS patients. This review presents an updated discussion on the epidemiology, pathophysiology, and associated comorbidities in HS, with a focus on pediatric and adolescent patients. It also suggests recommendations for investigation and treatment based on current evidence.

Gastrointestinal involvement of primary skin diseases

Less is known about gastrointestinal (GI) involvement of primary skin diseases due to the difference in embryology, histology, microbiology and physiology between integument and alimentary tract. Oesophagus, following the oropharyngeal mucosa, is the most common GI segment affected by primary skin diseases, especially by eosinophilic oesophagitis, lichen planus and autoimmune bullous dermatoses like pemphigus vulgaris, mucosal membrane pemphigoid and epidermolysis bullosa acquisita. Eosinophilic oesophagitis is an emerging chronic atopic disease with oesophageal dysfunction as the typical presentation, and oesophageal narrowing, rings and stricture as late complications. Oesophageal lichen planus mainly involves the proximal to mid-oesophagus in elderly aged women with long-term oral mucosal lesions. In acute attack of pemphigus vulgaris, oesophageal involvement is not uncommon but often neglected and may cause sloughing oesophagitis (oesophagitis dissecans superficialis) with acute GI bleeding in rare cases. GI manifestation of hereditary bradykininergic angio-oedema with colicky acute abdomen mostly affects small intestine, usually in the absence of pruritus or urticaria, and is more severe and long-lasting than the acquired histaminergic form. Strong evidence supports association between inflammatory bowel disease, especially Crohn disease, and hidradenitis suppurativa/acne inversa. Patients with vitiligo need surveillance of autoimmune liver disease, autoimmune atrophic gastritis or coeliac disease when corresponding symptoms become suspect. Melanoma is the most common primary tumour metastatic to the GI tract, with small intestine predominantly targeted. Gastrointestinal involvement is not uncommon in disseminated mycosis fungoides. Extramammary Paget's disease is an intraepidermal adenocarcinoma of controversial origin, and a high association between the anogenital occurrence and colorectal adenocarcinoma has been reported. As GI tract is the largest organ system with multidimensional functions, dermatologists in daily practice should be aware of the gastrointestinal morbidities related to primary skin diseases for an early diagnosis and treatment.

Questionnaire-based epidemiological study of hidradenitis suppurativa in Japan revealing characteristics different from those in Western countries

Hidradenitis suppurativa (HS) is a chronic relapsing skin disease localized mainly on the apocrine gland‐bearing areas. In Japan, HS is yet to be fully understood, and no criteria have been established for its diagnosis or severity assessment. The purpose of this study was to investigate and characterize HS in Japan. We conducted a nationwide questionnaire‐based study, in which Japanese diagnostic criteria were proposed. Question items included age, sex, disease duration, past history, family history, smoking status, disease severity scores (Hurley stage, modified Sartorius score and Physician Global Assessment [PGA] score), treatments, comorbidities and prognosis. We analyzed 300 patients (219 males and 81 females) diagnosed with HS based on our criteria. Average disease duration was 92.3 ± 6.82 months. Only 12 (4%) patients had a family history of HS. Disease severity was classified by PGA score (mild, 100 [33.3%]; moderate, 133 [44.3%]; severe, 34 [11.3%]; most severe, 29 [9.7%]) and Hurley stage (I, 69 [23%]; II, 109 [36.3%]; III, 121 [40.3%]). Disease severities based on PGA score and Hurley stage were positively correlated to modified Sartorius score using the Kruskal–Wallis test (P < 0.001, respectively). Patients with diabetes mellitus showed higher PGA scores (χ² = 10.977, P = 0.01185). Presence of axillary lesions related to higher PGA scores (χ² = 8.6378, P = 0.03452). The results in this study and previous studies indicate that Japanese HS patients have different backgrounds from those in Western countries, and are characterized by male predominance, higher incidence of Hurley stages II and III, higher PGA scores in patients with axillary lesions and much fewer familial cases.

Novel Mutation of the NCSTN Gene Identified in a Chinese Acne Inversa Family

Acne inversa is a chronic inflammatory follicular disease with autosomal dominant inheritance. In recent years, many functional mutations in the NCSTN genes have been identified as the cause of familial acne inversa. Herein, we recruited four patients and seven unaffected individuals from a Chinese family and performed Sanger sequencing of the NCSTN gene. One novel frameshift mutation, c.450_459del (p.Ser 151GlnfsX48), was identified in exon 5 of the NCSTN gene. Three normal-looking children carrying the mutation were proven to be patients. We also presented a literature review from previous studies of acne inversa, suggesting that NCSTN is a hotspot gene for acne inversa. Most affected individuals experienced onset in adolescence. We confirmed the diagnosis in this family based on the mutation. This finding will help expound the relationship between the NCSTN gene and the pathogenesis of acne inversa and emphasize the value of genetic diagnosis in monogenic disorder.

Prevalence and cutaneous comorbidities of hidradenitis suppurativa in the German working population

The association of hidradenitis suppurativa with other skin diseases has not yet been investigated in larger studies based on dermatological exams. The objectives of this study are to determine the prevalence and cutaneous comorbidities of hidradenitis suppurativa in the German working population. Between 2014 and 2017, 20,112 people in 343 German companies were examined for the presence of clinical features of hidradenitis suppurativa within the framework of a cross-sectional epidemiological study based on whole-body examinations. In addition, all cutaneous comorbidities were recorded. Point prevalence was calculated and the differences between individuals with and without hidradenitis suppurativa were determined by bivariate analysis. All statistical procedures were performed using SPSS 23.0 for Windows. Of 20,112 people examined, mean age was 43.6 ± 10.5 years; 52.3% were male. In total, n = 57 people (0.3%) with hidradenitis suppurativa were identified; 61.4% (n = 35) being male. In addition, non-inflammatory hidradenitis suppurativa-related lesions were found in 674 other individuals. In a bivariate comparison, patients with hidradenitis suppurativa showed significantly more frequently the following cutaneous comorbidities: acne vulgaris, psoriasis, seborrhoeic dermatitis, excoriations, and folliculitis. We determined a point prevalence of hidradenitis suppurativa of 0.3%. Since we have examined the working population, the healthy worker effect, which could have led to underestimation of prevalence, cannot be ruled out. The point prevalence of 0.3% for employed people in Germany and a prevalence of 3.0% for inflammatory and non-inflammatory hidradenitis suppurativa-related lesions show that hidradenitis suppurativa is an important disease for the whole health system.

Reconstruction of bilateral inferomedial gluteal defects after resection of hidradenitis suppurativa with symmetrical keystone flaps designed parallel to relaxed skin-tension lines: A case report

RATIONALE

Surgical treatment of hidradenitis suppurativa (HS) is challenging. Wide excision of affected lesions followed by skin graft or flap coverage has been recommended to achieve remission and prevent recurrence. Herein, we present our experience of bilateral inferomedial gluteal defects coverage using symmetrical keystone flaps (KFs) designed parallel to relaxed skin-tension lines (RSTLs).

PATIENT CONCERNS

An 18-year-old man was admitted for chronic inflammatory lesions in both inferomedial gluteal areas.

DIAGNOSES

Physical examination revealed multiple sinuses with broad surrounding scars in both inferomedial gluteal areas, which led to a diagnosis of HS.

INTERVENTIONS

We performed wide excision on all affected lesions. The size of the final defects was 6 × 10 cm on the right side, and 5 × 9 cm on the left side. We covered the defects with KFs 9 × 15 cm (right) and 8 × 12 cm (left), which were based on the hotspots of the interior gluteal artery and internal pudendal artery perforators, and parallel to RSTLs.

OUTCOMES

The flaps were inset without tension on each side, and the donor sites were closed primarily. All flaps fully survived and there were no postoperative complications. The patient was satisfied with the final outcome after 6 months of follow-up.

LESSONS

Successful reconstruction of bilateral inferomedial gluteal defects was achieved after resection of HS using symmetrical KFs designed parallel to RSTLs. The KF technique considering RSTLs could be a good reconstructive option for gluteal HS.

Hidradenitis suppurativa

Hidradenitis suppurativa (HS; also designated as acne inversa) is a chronic inflammatory disorder, which affects the intertriginous skin and is associated with numerous systemic comorbidities. The estimated prevalence of HS is ~1% in most studied countries. Typically starting in early adulthood, cutaneous inflamed nodules, abscesses and pus-discharging tunnels develop in axillary, inguinal, gluteal and perianal body sites. The comorbidities of HS include metabolic and cardiovascular disorders, which contribute to reduced life expectancy. A genetic predisposition, smoking, obesity and hormonal factors are established aetiological factors for HS. Cutaneous changes seem to start around hair follicles and involve activation of cells of the innate and adaptive immune systems, with pivotal roles for pro-inflammatory cytokines such as tumour necrosis factor, IL-1β and IL-17. The unrestricted and chronic immune response eventually leads to severe pain, pus discharge, irreversible tissue destruction and scar development. HS has profound negative effects on patients' quality of life, which often culminate in social withdrawal, unemployment, depression and suicidal thoughts. The therapeutic options for HS comprise antibiotic treatment, neutralization of tumour necrosis factor and surgical intervention together with lifestyle modification. Nevertheless, there is an enormous need for awareness of HS, understanding of its pathogenesis and novel treatments.

Review of Comorbidities of Hidradenitis Suppurativa: Implications for Daily Clinical Practice

Hidradenitis suppurativa (HS) is a chronic, recurrent skin inflammatory disease associated with a variety of comorbidities, like reduced quality of life, metabolic syndrome, sexual dysfunction, working disability, axial spondyloarthritis, inflammatory bowel disease, depression, and anxiety. Like psoriasis, HS patients have been found to have higher risk of cardiovascular death and suicide risk. Clinicians should be informed about these comorbidities so that appropriate screening is implemented. All this evidence suggests that for such a chronic, multi-comorbid disease, the use of validated outcomes to assess severity and effect of treatment, along with the use of clinically important patient reported outcomes, is essential. The potential of available treatments to negatively and positively affect these comorbidities should also be taken into account when designing treatment strategies. This review provides an outline of important HS comorbidities with emphasis on possible implications for daily clinical practice.

Global prevalence of hidradenitis suppurativa and geographical variation—systematic review and meta-analysis

Background

There is a significant variation in the reported prevalence of hidradenitis suppurativa (HS), ranging from 0.03–4%. We hypothesized that this significant variation may be due to different prevalence rates of HS according to geographical location as well as sex.

Objective

We aimed to perform a meta-analysis to determine pooled overall prevalence of HS, prevalence stratified according to geographical region and sex.

Materials and methods

A systematic review was performed by searching Ovid Medline, PubMed, Cochrane Library, DARE, and Embase, from inception to August 2018. A systematic review and meta-analysis was performed according to PRISMA guidelines. A meta-analysis of proportions was performed to determined pooled prevalence rates, with meta-regression based on geographic region. Prevalence in males versus females was also performed according to region.

Results

The overall pooled prevalence rate was 0.3% (0.2–0.6%) based on 118,760,093 HS cases available. Subgroup analysis demonstrated prevalence differences, with the highest being in Europe 0.8% (0.5–1.3%), compared to 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%). Prevalence in males was lower compared to females in the USA (OR 0.403, 95% CI 0.37–0.439, P < 0.001) as well as in Europe (OR 0.635, 95% CI 0.397–1.015, P = 0.08) but not in the Asia-Pacific region (OR 0.936, 95% CI 0.319–2.751, P = 0.78).

Conclusion

Prevalence of HS varies significantly according to the geographical population. This variation is likely attributed to different ethnicity distributions amongst different continents.

Level of evidence

III

Hidradenitis suppurativa and acne vulgaris and conglobata—systematic review and meta-analysis

Background

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder which involves painful nodules and draining abscesses in flexural areas. Acne vulgaris and its more severe variants including acne conglobata and acne fulminans are also disorders involving the follicular unit. Given that follicular obstruction, dilatation and inflammation feature in both HS and acne vulgaris/conglobata, it has been suggested that HS is associated with acne vulgaris/conglobata.

Methods

The present systematic review and meta-analysis was performed according to recommended PRISMA guidelines. All eligible case-control studies comparing patients with HS vs non-HS were included in the present review. All studies must have included either the proportion of patients with acne vulgaris/conglobata in each group, or the summary effect size for association between HS and acne vulgaris/conglobata. The odds ratio (OR) was used as a summary statistic.

Results

From pooled unadjusted meta-analysis, we found a significantly higher proportion of patients with acne vulgaris/conglobata in HS cases compared to controls (OR 3.44, 95% CI 1.95–6.07, P < 0.0001, I2 = 100%). Pooled meta-analysis was also performed with adjusted effect sizes. This demonstrated that HS was significantly associated with acne vulgaris/conglobata after adjustment for potential confounders (OR 3.44, 95% CI 2.43–4.87, P < 0.00001, I2 = 99%).

Conclusions

In summary, a significant association was found between HS and acne vulgaris/conglobata. This has implications in terms of understanding the burden of disease on patient quality of life as well as consideration of optimal management strategies to target both disorders. Physicians taking care of patients with HS should be aware of this association.

Earwax of patients with hidradenitis suppurativa: A retrospective study

Background

In Western nations, hidradenitis suppurativa (HS) typically affects the apocrine gland-bearing skin of people of African origin, women, smokers, and individuals with obesity. The clinical characteristics of HS in Korea and Japan, however, are reportedly different from those in the West. We therefore hypothesized that wet earwax is associated with HS because most East Asian people are genetically predisposed to produce dry earwax.

Methods

The medical charts of 53 Japanese patients with HS were reviewed retrospectively.

Results

Unlike the results of surveys conducted in Western nations, most of our patients were men (72%), whose buttocks were the most commonly affected site. Apocrine gland-bearing areas, such as the axilla, were affected less often. The proportion of HS patients with wet earwax was 51%, which was substantially higher than that found in the general Japanese population. Moreover, when patients with gluteal HS were excluded, the proportion of patients with wet earwax became even higher (68%).

Conclusions

Although the etiology of HS is unknown, our survey indicated that HS in apocrine gland-bearing skin, such as the axillary and anogenital areas, may be associated with wet earwax. As this study was conducted in a limited clinical setting, a nationwide, multicenter survey is warranted to clarify the clinical characteristics of HS in Japan.

Hidradenitis Suppurativa and Thyroid Disease: Systematic Review and Meta-Analysis

Background:

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by painful nodules, sinus tracts, and significant scarring. Although the pathogenesis of this disease is not well established, there is increasing evidence to suggest that it is an immune-mediated disorder. Previous studies have suggested a relationship between HS and thyroid disease, which is also driven by an autoimmune process. We sought to assess whether an association exists between HS and thyroid disease.

Objectives:

To determine whether HS is associated with thyroid disease via meta-analysis of case-control studies.

Methods:

A systematic review and meta-analysis was performed according to recommended PRISMA guidelines. Electronic searches were performed using 6 electronic databases from their inception until August 2018. Data were extracted and analyzed according to predefined clinical endpoints. Odds ratio (OR) was used as the summary effect size.

Results:

We identified 5 case-controls studies included for meta-analysis. There were a total of 36 103 HS cases compared with 170 517 control cases. We found a significant association between HS and thyroid disease (OR 1.36, 95% CI 1.13-1.64, I 2 = 78%, P = .001).

Conclusions:

This pooled analysis of existing case-control studies to date supports an association between HS and any thyroid disease. Clinicians treating patients with HS should be aware of this potential association with thyroid disease.

Twenty-four-week interim analysis from a phase 3 open-label trial of adalimumab in Japanese patients with moderate to severe hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by recurrent painful inflamed nodules/abscesses and draining fistulas that negatively impact quality of life. Adalimumab, a monoclonal antibody against tumor necrosis factor‐α, has been approved in the EU, USA and Japan for the treatment of moderate to severe HS. This is an interim analysis of an ongoing phase 3, multicenter, open‐label, single‐arm study of the safety and efficacy of adalimumab weekly dosing in Japanese patients with moderate to severe HS. Fifteen patients received adalimumab 160 mg at week 0, 80 mg at week 2 and 40 mg every week thereafter starting at week 4. The fulfillment of Hidradenitis Suppurativa Clinical Response was assessed under adalimumab treatment; clinical response was assessed by skin pain, total abscess and inflammatory nodule count and modified Sartorius score; and quality of life and safety were assessed. At week 12, 86.7% of patients achieved clinical response, with improvements at week 12 across the primary and secondary end points generally sustained through week 24. Adalimumab weekly dosing was generally safe and well tolerated with no new safety findings through week 24. These results suggest that adalimumab is effective and well tolerated in Japanese patients with moderate to severe HS.

Hidradenitis suppurativa and metabolic syndrome - systematic review and adjusted meta-analysis

BACKGROUND

Hidradenitis suppurativa (HS) is a debilitating and distressing chronic systemic inflammatory skin disease. There have been several prior observational studies which reported a possibility link between HS and metabolic syndrome, however the current evidence is not definitive. It is unclear in HS whether this possible relationship is independent or driven by underlying risk factors and comorbidities.

OBJECTIVE

To determine whether HS is independently associated with metabolic syndrome via adjusted meta-analysis of case-control studies.

METHODS

A systematic review and meta-analysis was performed according to PRISMA guidelines. Electronic searches were performed using six electronic databases (Ovid Medline, PubMed, CCTR, CDSR, ACP Journal Club, and DARE) from their inception until September 2018. Data were extracted and analyzed according to predefined clinical endpoints.

RESULTS

We identified six case-control studies included for meta-analysis. Based on unadjusted analysis, we found a significant association between adult cases of HS and metabolic syndrome (OR 1.95, 95% CI 1.31-2.89, P = 0.001). Adjusted meta-analysis, after adjustment for age, sex, other cardiovascular risk factors, and comorbidities, found a significant association (OR 2.19, 95% CI 1.70-2.81, I²  = 32%, P < 0.00001).

LIMITATIONS

Studies reviewed were observational by design which are susceptible to bias, and there was lack of randomization. The quality of the current systematic review is also limited by the quality of available evidence which was predominantly observational in nature.

CONCLUSIONS

This pooled analysis of existing case-control studies supports an association between HS and metabolic syndrome. Clinicians treating patients with HS should be aware of this potential association.

Hidradenitis suppurativa and diabetes mellitus: updated systematic review and adjusted meta-analysis

BACKGROUND

Hidradenitis suppurativa (HS) is a debilitating and distressing chronic inflammatory skin disease. There is also evolving evidence supporting the association between HS and cardiovascular risk factors, including smoking, obesity, hyperlipidaemia and metabolic syndrome. Notably, these are clinical features and risk factors that are closely associated with type 2 diabetes mellitus (DM).

AIMS

We performed a pooled adjusted meta-analysis of comparative studies to investigate the relationship between HS and DM.

METHODS

A systematic review and meta-analysis was performed according to recommended Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. OR was used as the summary effect size.

RESULTS

From pooled analysis of unadjusted data from 12 studies, we found a significantly higher proportion of DM in HS cases compared with non-HS healthy controls (16.1% vs. 15.7%; OR = 2.17; 95% CI 1.85-2.55; P < 0.001). Adjusted effect sizes from five studies were also pooled. A significantly higher proportion of DM was found for HS compared with healthy controls, although the effect size was attenuated compared with unadjusted analyses (OR 1.69; 95% CI 1.50-1.91; P < 0.001).

CONCLUSIONS

To our knowledge, our systematic review and meta-analysis is the first to pool adjusted effect sizes. We found that HS was associated with a 1.69-fold increased odds of diabetes; however, the absolute risk difference was small (16.1% vs. 15.7%) and is probably not clinically relevant. Treating clinicians should be aware of this association, but there may not be an urgent need to perform screening for impaired glucose tolerance or diabetes.

Overall and subgroup prevalence of pyoderma gangrenosum among patients with hidradenitis suppurativa: A population-based analysis in the United States

BACKGROUND

Hidradenitis suppurativa (HS) and pyoderma gangrenosum (PG) are reported to coexist, although the prevalence of PG among patients with HS has not been systematically evaluated.

OBJECTIVE

To evaluate PG prevalence among patients with HS.

METHODS

Cross-sectional analysis of adults with PG among patients with HS and patients without HS through use of electronic health records data from a population-based sample of 55 million patients.

RESULTS

The prevalence of PG among 68,232 patients with HS was 0.18% (125 of 68,232), compared with 0.01% (1835 of 31,435,166) among those without HS (P < .0001). Prevalence was markedly higher among patients with HS and Crohn's disease (CD) (3.68%) than among patients with HS but without CD (0.12%). The odds of having PG were 21.14 (95% confidence interval [CI], 17.51-25.51) times greater among patients with HS than among those without HS. Patients with HS with CD had 12.38 (95% CI, 9.15-16.74) times the odds of having PG than did patients without HS but with CD. Among patients without CD, compared with patients without HS, those with HS had 26.51 (95% CI, 21.07-33.36) times the odds of having PG.

LIMITATIONS

We could not establish HS phenotype among those having coexistent PG, nor could we distinguish syndromic from nonsyndromic cases.

CONCLUSION

Patients with HS have an increased prevalence of PG, regardless of CD status. Painful ulcerations among patients with HS warrant additional evaluation for PG.