Hidradenitis suppurativa and Crohn’s disease link

Researchers writing in JAMA Dermatology report that patients diagnosed with hidradenitis suppurativa (HS) are at a higher risk for having or developing Crohn’s disease (CD). As such, HS patients with gastrointestinal symptoms suggestive of CD should be evaluated further, with the dermatologist maintaining an important role in optimizing multidisciplinary management in these patients.

“The link between HS and Crohn’s disease is one of those associations that we do not want to miss because both diseases are serious and have significant impact on patients’ health. Having an awareness of this association and taking a thorough review of symptoms will help us to recognize this comorbidity in a timely manner,” said the study’s author, Amit Garg M.D. of Northwell Health in New York.

Dr. Garg and colleagues conducted a study to evaluate the prevalence of CD among patients with HS in the United States and to determine the strength of association between the two diseases. Data was reviewed from 51340 patients (35000 women) with HS who were identified using electronic health records data that included information from more than 50 million unique patients across all US census regions.

Of the 51340 HS patients, 29010 (56.5%) were aged 18 to 44 years, followed by 17580 (34.2%) aged 45 to 64 years, and 4750 (9.3%) aged 65 years or older. The prevalence of CD among patients with HS was 2.0% compared to 0.6% among those without HS. The prevalence of CD was greatest among patients with HS who were white (2.3%), aged 45 to 64 years (2.4%), nonobese (2.8%), and tobacco smokers (2.3%). Patients with HS were also shown to have over three times the risk of having CD compared to patients without HS. It was found that CD was associated with HS across all patient subgroups, which was seen to be stronger in men, patients aged 45 to 64 years, nonobese patients, and nonsmokers.

Hidradenitis suppurativa is a chronic debilitating inflammatory disease affecting the apocrine glands in the intertriginous skin typically presenting as painful, deep-seated, inflamed nodules with potential to suppurate and fistula formation. The disease may also be associated with several comorbidities that can further significantly impact the patient’s health including spondyloarthropathy, dyslipidemia, allergic hypersensitivity reactions, inflammatory bowel disease, polycystic ovary syndrome, psychiatric disorders, obesity, drug dependence, hypertension, diabetes, lymphoma, and thyroid disease^2-3.

There are several features that are shared between HS and CD in particular. Both are inflammatory diseases involving epithelia characterized by suppuration, granulomatous inflammation, and the formation of fistulas and sinus tracts. The two conditions have similar ages of onset and both have been linked to tobacco smoking and arthritis. In addition, both diseases appear to share inflammatory pathways as well as susceptibility genes. As such, it is not unexpected that patients with one disease may develop the other. Although rare, CD may also manifest itself on the skin and resemble HS, making it sometimes challenging to distinguish between a cutaneous manifestation of CD and the disease HS.

According to Dr. Garg, any patient with HS who has a positive review of systems for CD should be screened for inflammatory bowel disease. This work-up may be initiated by the patient’s primary care physician, or by referral to a gastroenterologist. If the patient is ultimately diagnosed with Crohn’s disease, then the dermatologist will likely be involved in the multidisciplinary approach to management of the patient, as existing and future therapies are likely to have overlapping efficacy in both conditions.

“There is certainly a lot more that we need to understand regarding the relationship between HS and Crohn’s disease, their coexistence and their potential influences on one another. In addition to having keen awareness of this Crohn’s disease as a comorbidity, we as dermatologists can also engage our HS patients in a smoking cessation plan that could ultimately impact the development, course and severity of diseases,” Dr. Garg said.

REFERENCES

Garg A, Hundal J, Strunk A. Overall and subgroup prevalence of crohn disease among patients with hidradenitis suppurativa: a population-based analysis in the united states. JAMA Dermatol. 2018 May 23. Doi: 10.1001/jamadermatol.2018.0878.

²Shlyankevich J, Chen AJ, Kim GE, Kimball AB. Hidradenitis suppurativa is a systemic disease with substantial comorbidity burden: a chart-verified case-control analysis. J Am Acad Dermatol. 2014 Dec;71(6):1144-50. doi: 10.1016/j.jaad.2014.09.012. Epub 2014 Oct 14.

³Fimmel S, Zouboulis CC. Comorbidities of hidradenitis suppurativa (acne inversa). Dermatoendocrinol. 2010 Jan;2(1):9-16. doi: 10.4161/derm.2.1.12490.

DISCLOSURES:
Dr. Garg serves as consultants to AbbVie, Pfizer, Janssen, Asana Biosciences