What is the recommended treatment approach for a patient with Crohn's disease and psoriasis?

Treatment Approach for Crohn's Disease with Psoriasis

Ustekinumab is the recommended first-line therapy for patients with both Crohn's disease and psoriasis, as it is FDA-approved for both conditions and provides effective treatment for both diseases simultaneously. 1, 2

Treatment Algorithm

First-line therapy:

• Ustekinumab (IL-12/23 inhibitor)
  • FDA-approved for both moderate to severe Crohn's disease and psoriasis 1
  • Demonstrated efficacy in phase 3 trials for Crohn's disease, including in patients who failed TNF inhibitor therapy 2
  • Adult dosing:
    • Initial IV induction dose based on weight
    • Maintenance: 90mg subcutaneously every 8-12 weeks 1

Alternative options (if ustekinumab is contraindicated or ineffective):

• TNF inhibitors (infliximab or adalimumab)
  • Effective for both psoriasis and Crohn's disease 2, 3
  • Important consideration: TNF inhibitors can paradoxically induce or exacerbate psoriasiform skin eruptions in some patients with Crohn's disease 2, 4
  • If psoriasiform eruptions develop while on TNF inhibitor therapy:
    • Standard psoriasis treatments may be used while continuing TNF inhibitor 2
    • If skin disease persists, discontinuation of TNF inhibitor may be necessary 2

Medications to AVOID:

• IL-17 inhibitors (secukinumab, ixekizumab, brodalumab)
  • Should be strictly avoided in patients with Crohn's disease 2, 3
  • Can cause paradoxical worsening of bowel disease and exacerbate Crohn's disease 2
  • In a 2012 study, secukinumab not only failed to improve Crohn's disease but worsened symptoms in some patients 2

Special Considerations

For mild Crohn's disease:

• Topical steroids such as budesonide may be used 5
• High-dose 5-ASA (aminosalicylates) has limited evidence but may be considered for mild cases 5

For mild psoriasis with Crohn's disease:

• Low-potency topical corticosteroids (class 6-7) for limited areas 6
• Topical calcineurin inhibitors (tacrolimus 0.1%) for long-term treatment to avoid skin atrophy 6
• Limit duration of topical corticosteroid use to 4 weeks 6

Disease monitoring:

• Regular follow-up to assess both skin and bowel disease activity
• Monitor for treatment-related adverse effects
• Early intervention with appropriate systemic therapy may improve long-term outcomes in both conditions 7

Important Caveats

1. Paradoxical reactions: TNF inhibitors can induce psoriasiform eruptions in approximately 10% of IBD patients, with higher risk in Crohn's disease patients, females, and smokers 2

2. Genetic and pathologic connections: There is a significant association between psoriasis and Crohn's disease, with shared inflammatory pathways involving TNF-alpha 8

3. Early intervention: Consider more aggressive treatment early in the disease course rather than prolonged use of topical therapies alone, especially in moderate to severe disease 7

4. Malignancy risk: Patients with both conditions should be monitored for potential increased risk of certain malignancies, though current evidence suggests biologic therapies do not significantly increase overall malignancy risk 2