Bridging Gut and Skin: What Dermatology APPs Need to Know About IBD

At the Masterclasses in Dermatology APP Institute, gastroenterologist Dr David Fudman gave APPs a crash course in managing patients who walk the line between inflammatory bowel disease (IBD) and dermatologic conditions.

In his engaging session titled “Inflammatory Bowel Disease Considerations for the Dermatology and Rheumatology APP,” Dr Fudman made it clear that “IBD is not rare; it is common,” affecting about 1% of the US population. Yet, diagnosis remains delayed, particularly for Crohn’s disease, with patients often seeing 3.5 physicians over 6 months before being properly diagnosed.

Dr Fudman urged APPs to rethink the classic presentation. “Making the early diagnosis: it’s not just diarrhea,” he warned, pointing out that right lower quadrant pain, weight loss, or unexplained fevers could be subtle red flags. He also championed the use of fecal calprotectin testing, noting that values under 40 µg/g can reliably rule out IBD in patients with irritable bowel syndrome-like symptoms.

Once diagnosed, managing IBD is not just about suppressing symptoms; it is about changing the disease course. “Lack of symptoms does not mean lack of disease activity,” Dr Fudman explained. “Objective data drives therapy.” He emphasized using endoscopic assessments, inflammatory markers, and disease severity indices to guide treatment decisions.

The treatment landscape for IBD has advanced, with nearly a dozen advanced therapies introduced in the last 15 years. From tumor necrosis factor (TNF) antagonists to IL-23 inhibitors and Janus kinase inhibitors, Dr Fudman offered attendees a practical algorithm for selecting and sequencing agents, especially when crossover exists with dermatologic therapies.

“After infliximab failure, upadacitinib outperforms IL-23s,” he noted, while in cases of prior vedolizumab failure, “infliximab is often the next best step.”

Therapeutic drug monitoring (TDM) was another key focus. Dr Fudman emphasized using both reactive and proactive TDM to prevent anti-drug antibodies and optimize long-term response. “Combination therapy lowers anti-TNF immunogenicity risks,” especially with agents like methotrexate or thiopurines.

Perhaps most forward-looking was Dr Fudman’s discussion on combining biologics. “If 1 is good, are 2 better?” he asked, pointing to real-world data and emerging trials suggesting combination therapy could benefit refractory IBD or cases with overlapping inflammatory conditions like psoriasis or axial arthritis.

For dermatology APPs navigating the complexities of shared patients, this session offered critical insights, strategic frameworks, and a strong reminder: When skin and gut inflammation intersect, collaboration is key.

Reference

Fudman D. Inflammatory bowel disease considerations for the dermatology and rheumatology APP. Presented at: Masterclasses in Dermatology APP Institute; October 11–12, 2025; Dallas, TX.