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Perianal Crohn’s Disease (pCD)
A patient’s guide to fistulas, abscesses, setons, and modern combined-modality care.
Perianal Crohn’s disease (pCD) is a distinct phenotype of Crohn’s that affects roughly 20–30% of patients during their lifetime. It can be the first sign of Crohn’s — or it can develop years after diagnosis. The good news is that modern care, combining biologics with carefully planned surgery, has changed outcomes dramatically over the last decade.
What is Perianal Crohn’s Disease?
Perianal Crohn’s disease (pCD) is a phenotype of Crohn’s that affects the skin, soft tissues, and structures around the anus. It can cause fistulas (abnormal tunnels), abscesses (collections of pus), skin tags, fissures, and strictures (narrowings). It affects roughly 1 in 5 to 1 in 3 patients with Crohn’s during their lifetime.
Common Diagnoses Within pCD
- Perianal abscess — an infection that needs drainage, usually urgently.
- Perianal fistula — an abnormal tunnel between the rectum/anal canal and the skin around the anus. Often follows abscess drainage.
- Anal fissure — a tear in the anal lining; in Crohn’s often atypical (lateral, multiple).
- Anal stricture — narrowing of the anal canal that can make stooling difficult.
- Anal skin tags — usually painless but can be a marker of underlying disease.
Why Imaging Matters
Modern pCD care relies heavily on MRI of the pelvis. MRI shows the precise anatomy of fistula tracts and abscess cavities, which guides both surgical and medical decisions. Examination under anesthesia (EUA) is often paired with MRI.
Treatment — Medical and Surgical Together
Modern pCD management combines biologics (such as infliximab, adalimumab, ustekinumab, or risankizumab) with surgical drainage and seton placement. Treatment plans are individualized; the goal is healing the fistula without compromising continence.
What to Ask Your Doctor
- Has my disease activity been imaged with MRI?
- What type of fistula do I have (simple vs. complex)?
- What biologic options am I a candidate for?
- Is a seton being placed, and what is the plan to remove it?
- What are the warning signs that I should call about?