Clinical Trials

Inclusion Criteria:

• Adults aged 18 or older.

• Archive terminal ileum biopsies available in the Mayo Clinic pathology archives.

• Documented diagnosis of:

  • Active Crohn’s disease, or

  • Inactive Crohn’s disease, or

  • No IBD vs UC

• Willing and able to provide informed consent.

Exclusion Criteria:

• Under 18 years of age.

• Has used topical or oral steroids two weeks prior to patch testing.

• Currently taking immunosuppression agents or is immunocompromised due to medical condition.

• No sunburn or rash at site of testing.

• Women who are breastfeeding or pregnant.

• Treatment with ultraviolet (UV) light (including tanning) during the two weeks prior to visit..

• Subjects unable to comply with patch test study requirements including multiple return visits and activity restrictions (e.g., protecting patch test area from excess moisture due to showering)

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 11/25/2025. Questions regarding updates should be directed to the study team contact.