Work

Inflammatory Bowel Disease Prevalence in Patients with Hidradenitis Suppurativa Using Prospective Symptom-Based Questionnaires and Fecal Calprotectin Testing

Year: 2025

Type: article

Abstract: Hidradenitis suppurativa (HS) is associated with inflammatory bowel disease (IBD). Using healthcare databases, an estimated 2.1% of patients with HS have IBD. Prospective screening of patients with HS with IBD sign/symptom-based questions and fecal calprotectin (FC) has not been studied. Our aim was to evaluate the prevalence of IBD in HS and the utility of a sign/symptom-based questionnaire and FC testing. All patients with HS attending two clinics were invited to participate. Information was collected on demographics, HS severity, and IBD risk factors. Fecal samples were returned by patients for calprotectin testing (≤ 50 μg/g = negative, 50–150 μg/g = borderline, ≥ 150 μg/g = positive). We recruited 150 patients including 124 women (82.7%) with a median age of 36 years and Hurley stage 2/3 disease (88.6%); 11 patients had established IBD (7.3%). Up to 44.7% of patients reported gastrointestinal symptoms. In 98 patients who returned a fecal sample for calprotectin measurement, 10 had previously diagnosed IBD (10.3%), 81 had a negative FC (82.7%), 13 had a borderline FC (13.3%) and 4 had a positive FC (4.1%). Among 4 patients with a positive result, 2 had known IBD (50%); 2 without established IBD were referred to gastroenterology and 1 had a negative endoscopy reporting an acute diarrheal illness at the time of their FC. The second patient was diagnosed with endoscopic and histologic Crohn’s disease. We report an IBD prevalence of 8%, higher than previous studies. Routine IBD sign/symptom-based assessment is currently recommended. In our study, this would result in a referral rate of 44.7%. Among 88 FC tests in patients without established IBD, 1 patient was diagnosed with incident occult Crohn’s disease. At a number needed to screen (NNS) of 88, routine evaluation of all patients with HS with FC may be justified especially prior to the use of interleukin (IL)-17 antagonists. Previous research has shown that patients with hidradenitis suppurativa (HS) are more likely to have inflammatory bowel disease (IBD). These studies have been carried out using databases that usually underestimate the prevalence of disease. We aimed to identify the prevalence of IBD in patients with HS attending hospital clinics and whether screening for IBD in patients with HS is worthwhile. We used a screening questionnaire and stool test called a fecal calprotectin. Current guidelines suggest the use of screening questions to detect IBD, referring patients with symptoms to a gastroenterologist. Fecal calprotectin has a very high predictive value in picking up inflammation in the intestines. Among 150 patients, the prevalence of IBD before screening was 7.3%. Using a questionnaire, 44.7% of patients’ signs or symptoms would necessitate referral to gastroenterology. Of 98 patients who returned a stool sample, 10 were already diagnosed with IBD. Of the remaining 88, only 2 patients had a high calprotectin. Both patients underwent a camera test to look at their intestines (endoscopy). One patient was diagnosed with IBD following this. With this one additional case, the overall prevalence of IBD was 8%. These results suggest that using screening questions alone would significantly overestimate IBD prevalence in HS, resulting in unnecessary gastroenterology referrals. Testing for IBD using fecal calprotectin identified 1 new case of IBD in 88 patients. Routine fecal calprotectin testing in HS may be worthwhile, especially before commencing biologic drugs that block interleukin (IL)-17, as these can worsen IBD.

Source: Dermatology and Therapy

DOI: 10.1007/s13555-025-01438-7