Treatment of Ulcerative Colitis and Psoriasis

Introduction to Medication Selection

• The American Academy of Dermatology recommends TNF inhibitors (adalimumab, infliximab) or ustekinumab (IL-12/23 inhibitor) as the preferred systemic therapies for patients with both ulcerative colitis and psoriasis, while IL-17 inhibitors must be strictly avoided due to the risk of IBD exacerbation 1, 2
• Infliximab is similarly effective for both conditions and can be used when adalimumab is not suitable, addressing the shared inflammatory pathways in both diseases 1, 3

Medication Considerations

• Ustekinumab (IL-12/23 inhibitor) is an excellent alternative, FDA-approved for both Crohn's disease and psoriasis, and demonstrated effectiveness in phase 3 trials for IBD, including in TNF-blocker failures 1, 2
• The AAD-NPF guidelines explicitly recommend avoiding IL-17 inhibitors in IBD patients (Strength of Recommendation C, Level of Evidence I) 1, 2

Management of Paradoxical Reactions

• If psoriasiform eruptions develop while on TNF inhibitor therapy for UC, the first attempt should be to add standard psoriasis treatments (topical corticosteroids, vitamin D analogues) while continuing the TNF inhibitor, achieving complete or partial skin clearance in 90% of cases 1, 2, 4

Critical Monitoring Requirements

• Screen for IBD symptoms in psoriasis patients before starting therapy, including chronic diarrhea, abdominal pain, rectal bleeding, and unintentional weight loss, as the prevalence of ulcerative colitis is 1.64-1.91 times higher in psoriasis patients versus controls 1, 2, 4, 5, 3
• Monitor for IBD exacerbation during psoriasis treatment, with new or worsening gastrointestinal symptoms warranting immediate gastroenterology referral (Strength of Recommendation A) 1, 2

Special Considerations

• TNF inhibitors combined with thiopurines or methotrexate show superior efficacy for UC remission compared to monotherapy, and this combination approach can benefit both the UC and psoriasis components 6
• JAK inhibitors (tofacitinib, upadacitinib) are FDA-approved for moderate-to-severe UC and should be reserved as second-line after TNF inhibitor failure 6

Increased Risk of Inflammatory Bowel Disease in Patients with Psoriasis

Epidemiology of IBD in Psoriasis

• Patients with psoriasis have approximately 2.5‑fold higher risk of Crohn’s disease and 1.7‑fold higher risk of ulcerative colitis compared with the general population. 7
• The prevalence ratio for Crohn’s disease in psoriasis cohorts versus control groups is 2.49. 7
• The prevalence ratio for ulcerative colitis in psoriasis cohorts versus controls ranges from 1.64 to 1.91. 7

Additional Risk in Psoriatic Arthritis

• Individuals with psoriatic arthritis, especially those with axial involvement, exhibit a higher incidence and prevalence of IBD than patients with skin‑only psoriasis. [8][9]

Screening Recommendations for IBD Symptoms

• Prior to initiating systemic psoriasis therapy, screen all patients for IBD‑related symptoms and continue monitoring during treatment. [8][9]
• Red‑flag symptoms that should prompt immediate gastroenterology referral include:

Therapeutic Considerations

• IL‑17 inhibitors (e.g., secukinumab, brodalumab, ixekizumab) should be avoided in patients with known or suspected IBD because clinical trials have shown they can exacerbate Crohn’s disease. [8][9]
• Methotrexate has demonstrated efficacy for both psoriasis and IBD and may be used in combination with biologic agents. [8][9]

Gastrointestinal Comorbidity Risk and Management in Psoriasis

Magnitude of Gastrointestinal Risk

• Psoriasis patients have a 24 % higher hazard of developing irritable bowel syndrome over a 15‑year follow‑up compared with matched controls (hazard ratio 1.24, 95 % CI 1.17–1.33) in a large population‑based cohort. Evidence level: high‑quality observational study. 10

• Inflammatory bowel disease risk is markedly elevated in psoriasis:

  • Crohn’s disease prevalence is approximately 2.5‑fold higher (prevalence ratio ≈ 2.5).
  • Ulcerative colitis prevalence is 1.7‑fold higher (prevalence ratio ≈ 1.6–1.9). Evidence level: cohort data from a dermatology‑gastroenterology registry. 11

• Subgroup analyses show greater IBS risk among women (hazard ratio ≈ 1.29) and patients aged ≥ 65 years (hazard ratio ≈ 1.33). Evidence level: subgroup analysis of the same cohort. 10

Screening and Patient Education

• All individuals with psoriasis should be counseled about their increased likelihood of both IBS and IBD and advised to report new gastrointestinal symptoms promptly. Evidence level: consensus recommendation based on multiple cohort studies. [10][12]13

Red‑Flag Gastrointestinal Symptoms Requiring Gastroenterology Referral

These symptoms should trigger immediate specialist evaluation in any psoriasis patient. *Evidence level: expert consensus. 14

Risk Stratification by Disease Severity

• Psoriatic arthritis, especially with axial involvement, confers a higher incidence and prevalence of IBD compared with skin‑only psoriasis, warranting heightened clinical vigilance. Evidence level: observational data linking arthritis phenotype to GI outcomes. 14

Treatment Considerations in the Presence of Gastrointestinal Comorbidity

• IL‑17 pathway inhibitors (e.g., secukinumab, brodalumab, ixekizumab) must be avoided in patients with known or suspected IBD because they can exacerbate Crohn’s disease. Evidence level: safety signal from post‑marketing surveillance and clinical trials. [10][12]13

• TNF‑α inhibitors (e.g., adalimumab, infliximab) and IL‑12/23 inhibitor (ustekinumab) are preferred when psoriasis coexists with IBD, as they are effective for both conditions. Evidence level: therapeutic guideline based on dual‑indication trial data. [10][12]13

Clinical Pitfalls

• Misclassifying IBD as IBS in psoriasis patients can lead to missed opportunities for early IBD treatment; IBD risk is substantially higher (approximately 150–250 % increase for Crohn’s disease) than the modest IBS risk increase. Evidence level: comparative risk analysis. [11][10][12][13]

Guideline Recommendations for Managing Psoriasis Patients at Risk of Inflammatory Bowel Disease

Patient Education

• The American Academy of Dermatology recommends that clinicians inform all patients with psoriasis about the increased risk of inflammatory bowel disease (IBD). This recommendation carries a Strength of Recommendation B. 15, 16

Medication Contraindications

• The American Academy of Dermatology–National Psoriasis Foundation (AAD‑NPF) guidelines state that IL‑17 inhibitors (secukinumab, brodalumab, ixekizumab) are contraindicated in patients who have or develop IBD because they can trigger or worsen Crohn’s disease. This carries a Strength of Recommendation C and Level of Evidence I. 15, 16
• Clinical trial evidence cited by the American Academy of Dermatology shows that IL‑17 blockade is ineffective for treating IBD and may precipitate disease flares. 15

Referral and Evaluation of Gastrointestinal Symptoms

• The AAD‑NPF advises that any psoriasis patient who develops persistent gastrointestinal symptoms (e.g., chronic diarrhea, nocturnal bowel movements, rectal bleeding, abdominal pain, perianal fistula/abscess, or unexplained weight loss) should receive prompt gastroenterology referral. This recommendation has a Strength of Recommendation A. 15, 16