FROM THE JOURNAL OF INVESTIGATIVE DERMATOLOGY

Individuals with hidradenitis suppurativa (HS) may be at significantly greater risk of inflammatory bowel conditions such as Crohn’s disease and ulcerative colitis, according to a Danish populationwide cohort study.

“In HS patients presenting with gastrointestinal complaints, timely referral for gastroenterological evaluation of IBD [inflammatory bowel disease] may be appropriate,” Alexander Egeberg, MD, of the University of Copenhagen and his coauthors wrote.

The study of 7,732 patients with a hospital diagnosis of HS, and 4,354,137 controls from the general population, found that the baseline prevalence of Crohn’s disease was twofold higher in individuals with HS, compared with the general population (0.8% vs. 0.3%; odds ratio, 2.04; P less than .0001), after adjustment for age, sex, socioeconomic status, health care consumption, smoking, and alcohol abuse.

Similarly, the incidence of ulcerative colitis was about 1.8-fold higher among individuals with HS, compared with controls (1.3% vs. 0.7%; OR, 1.75; P less than .002), and the incidence of “unspecified” inflammatory bowel disease was 3.4-fold higher (0.7% vs. 0.1%; OR, 3.40; P less than .007), according to a paper published online in the Journal of Investigative Dermatology.

Dr. Egeberg and his coauthors reported that HS and inflammatory bowel disease similarities suggest a shared pathogenesis, including the worsening effect of smoking on both conditions; the appearance of scarring and sinus tract formation; the apparent involvement of T-helper 17 cells, interleukin-23, and tumor necrosis factor; and the coinvolvement of genes such as SULT1B1 and SULT1E1 ( J Invest Dermatol. 2017 Jan 13. doi: 10.1016/j.jid.2016.11.040 ).

“Finally, an increased prevalence of spondylarthropathy has been reported in patients with IBD as well as in those with HS, raising the hypothesis that genetic, epigenetic, and/or environmental factors cooperate to lead to dysregulated inflammatory pathways across these immune-mediated diseases,” the authors wrote.

While previous study evidence linking HS and IBD has been inconsistent, the authors said their findings suggested an increased incidence of IBD in individuals with HS – ranging from 0.13 to 0.97 per 1,000 HS patients per year.

They acknowledged that the study population was predominantly of Northern European descent, and the results might not be generalizable to patients of other ethnicities. They also noted that patients with HS identified by hospital diagnoses may therefore have had greater comorbidity than patients sampled from a population setting.

The study was funded by Eli Lilly, and one author is an employee of Eli Lilly. Five other authors declared research funding, grants, consultancies, honoraria, consultancy, and board positions for various pharmaceutical companies, including Eli Lilly.

dermnews@frontlinemedcom.com

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