Abstract
Perianal fistulising Crohn's disease (PFCD) affects up to 20% of patients with Crohn's disease (CD) and is a complex and challenging form of CD that can result in a significant illness burden. Despite recent advances in PFCD classification systems, disease activity can be challenging to monitor on an ongoing basis when compared to luminal CD where biomarkers, imaging and colonoscopy are readily utilised in a "treat to target" approach.