New-Onset Collagenous Colitis in a Patient With Psoriatic Arthritis: Can It Be Secukinumab?

Collagenous colitis is a chronic inflammatory condition and one type of a bigger entity, microscopic colitis. Collagenous colitis is associated with autoimmune diseases, such as psoriatic arthritis, suggesting an immune mechanism involved in the pathogenesis of the disease. New onset and flares of inflammatory bowel disease have been associated with the use of secukinumab, but no cases of microscopic colitis have been reported yet. We present a case of a 41-year-old woman with psoriatic arthritis treated with secukinumab who developed chronic diarrhea and was found to have collagenous colitis.