NEW YORK (Reuters Health) - Patients with hidradenitis suppurativa (HS), a skin disorder characterized by painful nodules and abscesses, may be at increased risk for Crohn's disease (CD), and those with GI symptoms should be seen by a gastroenterologist, researchers in New York say.
"HS and CD share several features, including inflammatory involvement of epithelia with suppuration and granulomatous inflammation, fistula and sinus tract formation, age of onset, link to tobacco smoking, link to arthritis, and potentially shared inflammatory pathways and susceptibility genes," Dr. Amit Garg of Hofstra/Northwell in New Hyde Park told Reuters Health.
"Indeed, we meet patients with HS who describe gastrointestinal symptoms consistent with CD," he said by email. "Although rare, CD may also manifest itself on the skin and resemble HS."
To assess the prevalence of and associations between the two conditions, Dr. Garg and colleagues conducted a cross-sectional analysis of U.S. national health data from 51,340 patients with HS (68% women). Of these, 56.5% were ages 18 to 44; 34.2%, 45 to 64; and 9.3%, 65 or older.
As reported online May 23 in JAMA Dermatology, the prevalence of CD was 2% among patients with HS compared with 0.6% among those without HS. CD prevalence was greatest among HS patients who were white (2.3%), ages 45 to 64 (2.4%), nonobese (2.8%), and tobacco smokers (2.3%).
Subsequent analyses showed that, overall, the odds of having CD were between 3.05 and 3.29 times greater among those with HS compared to those without.
CD was associated with HS across all age groups; however, the association was strongest for men (OR, 3.61), those ages 45 to 64 (OR, 3.49), nonobese individuals (OR, 4.09), and nonsmokers (OR, 3.44).
"There is certainly more we need to understand about the relationship between these two conditions and their overlapping features," Dr. Garg said. Nonetheless, "given that 2% of patients with HS also have CD, HS patients demonstrating symptoms or signs suggestive of CD warrant additional evaluation."
Dr. Ross Levy, Director of Dermatology, Mount Sinai Health System at CareMount Medical in Mount Kisco, New York, told Reuters Health, "The evidence over the last two decades supports an association between the two diseases."
"The concept of dysregulation of the immune system fits for both, and the innate and adaptive immune systems respond in a similar way: in HS, ruptured follicular ducts release antigens, and . . . in CD, antigens are released from the gut," he said by email. "The microscopic histology is similar in both processes."
"The new treatments with 'biologics' further press the case for a similarity, in that both CD and HS have a response to TNF-alpha treatment," he added.
"Both dermatologists and gastroenterologists need to be aware of this association so that their patients can receive optimal care," he concluded. "A careful history, both personal and family, must be a part of the evaluation to effect appropriate referrals."
Dr. Lisa Malter, a gastroenterologist at NYU Langone Health in New York City, said in an email to Reuters Health, "The cross-referral absolutely makes sense. If a patient with HS has bowel symptoms or unexplained iron deficiency, they should absolutely be evaluated by a gastroenterologist."
"The assessment should not be delayed, as there is increasing evidence that early aggressive treatment of CD helps avoid disease complications and improves outcomes," she added. "I have a small group of patients in my own practice with both disease states and I routinely partner with dermatology to ensure the best diagnostic evaluation and treatment for the patient."
The study was sponsored in part by AbbVie. Dr. Garg receives fees from the company.
provided by Medscape.