How should I treat a patient with jejuno‑ileal enteritis and a 10 mm asymmetrically enlarged appendix, who also has psoriatic arthritis and oral lichen planus and is currently on a disease‑modifying antirheumatic drug?

Management of Jejuno-Ileal Enteritis with Asymmetrically Enlarged Appendix in a Patient on DMARD Therapy for Psoriatic Arthritis

You must immediately evaluate for inflammatory bowel disease (IBD) and consider switching from your current DMARD to a TNF inhibitor or IL-23 inhibitor (such as infliximab, adalimumab, guselkumab, or risankizumab) that effectively treats both psoriatic arthritis and IBD, while avoiding etanercept and JAK inhibitors that may worsen or unmask intestinal inflammation 1, 2.

Immediate Clinical Assessment

The combination of jejuno-ileal enteritis in a patient with psoriatic arthritis raises critical concerns:

• IBD-associated spondyloarthritis occurs in approximately 15% of IBD patients, and musculoskeletal symptoms can precede IBD diagnosis in 25% of cases 1
• The 10mm asymmetric appendiceal enlargement combined with small bowel inflammation suggests active inflammatory bowel disease requiring urgent gastroenterological evaluation
• Your current DMARD choice is critical—certain agents can paradoxically induce or worsen intestinal inflammation

Critical Drug Considerations for Your Patient

Agents to AVOID:

Etanercept is contraindicated in this clinical scenario. This TNF inhibitor is intestinally inactive and has been directly implicated in unmasking or inducing Crohn's disease in patients with psoriatic arthritis 2. A documented case showed a patient developing active colitis with ulcerations and non-caseating granulomas after switching to etanercept for psoriatic arthritis treatment.

JAK inhibitors require extreme caution. While upadacitinib successfully treated refractory oral lichen planus in one psoriatic arthritis patient 3, recent EULAR guidelines emphasize worldwide safety concerns regarding JAK inhibitors 4. Given your patient's intestinal inflammation, the risk-benefit ratio is unfavorable.

Sulfasalazine should be avoided as it can induce lichen planus 5, worsening your patient's existing oral lichen planus.

Preferred Therapeutic Options:

TNF inhibitors (excluding etanercept) are first-line for IBD-associated spondyloarthritis:

• Infliximab, adalimumab, certolizumab, or golimumab effectively treat both psoriatic arthritis and IBD 4, 1
• These agents address the intestinal inflammation while controlling joint disease

IL-23 inhibitors (guselkumab or risankizumab) represent an excellent alternative:

• Approved for psoriatic arthritis 4
• Effective for Crohn's disease
• Risankizumab specifically improved refractory oral lichen planus when switched from secukinumab in a psoriatic arthritis patient, resolving the lesion within 4 weeks without candidiasis recurrence 6
• IL-23p19 inhibitors do not affect the oral mycobiome, making them particularly suitable for your patient's oral lichen planus

Ustekinumab (IL-12/23 inhibitor) is another strong option:

• Successfully induced remission in both psoriatic arthritis and new-onset Crohn's disease in a patient who developed IBD on etanercept 2
• Addresses cutaneous, joint, and gastrointestinal manifestations simultaneously

Management Algorithm

1. Obtain urgent gastroenterology consultation for colonoscopy with terminal ileum intubation and biopsy to confirm IBD diagnosis and assess disease extent

2. If currently on etanercept, apremilast, or JAK inhibitor: Discontinue immediately and switch to:

   • First choice: Risankizumab or guselkumab (addresses PsA, potential IBD, and oral lichen planus)
   • Alternative: Infliximab or adalimumab (proven efficacy in IBD-associated SpA)

3. If currently on IL-17 inhibitors (secukinumab, ixekizumab, bimekizumab):

   • These can induce or worsen oral lichen planus through IL-17-mediated changes in oral mycobiome 6
   • Switch to IL-23 inhibitor (risankizumab/guselkumab) or TNF inhibitor

4. Monitor for appendicitis: The 10mm asymmetric enlargement requires surgical consultation if patient develops fever, right lower quadrant peritoneal signs, or worsening symptoms

5. Address oral lichen planus:

   • Topical management with clobetasol gel or dexamethasone rinses as adjunct
   • Systemic therapy choice (as above) will be definitive treatment
   • Avoid topical calcineurin inhibitors if immunosuppression is already significant

Key Pitfalls to Avoid

• Do not continue etanercept in the presence of intestinal symptoms—it cannot induce T-cell apoptosis in intestinal mucosa and may worsen IBD 2
• Do not assume the appendiceal finding is incidental—asymmetric enlargement with small bowel inflammation suggests IBD involvement
• Do not use sulfasalazine despite its traditional role in spondyloarthritis—it will exacerbate the oral lichen planus 5
• Do not overlook the temporal relationship between DMARD initiation and symptom onset—drug-induced enteritis is possible

Integration of Comorbidities

Per EULAR 2024 guidelines, when managing psoriatic arthritis, non-musculoskeletal manifestations (skin, eye, and gastrointestinal tract) must be considered in treatment decisions 4. Your patient exemplifies this principle with three distinct inflammatory manifestations requiring a unified therapeutic approach. The IL-23 inhibitors (particularly risankizumab) or non-etanercept TNF inhibitors represent the optimal strategy to address all disease domains simultaneously 1, 6.