Perianal Crohn’s (Fistulas, Abscesses, Skin Tags)

Perianal Crohn’s disease affects the skin and tissues around the anus. It can cause fistulas, small tunnels that connect the bowel to the skin, and abscesses, pockets of infection. Care works best when gastroenterology and colorectal surgery teams plan together. The goals are to control infection, close fistulas when possible, protect continence, and keep rectal inflammation quiet. (journals.lww.com)

Key takeaways

• Pelvic MRI and an exam under anesthesia map tracts and drain any abscess before starting immune therapy. (pubmed.ncbi.nlm.nih.gov)

• Complex fistulas usually need seton drainage plus an anti‑TNF medicine, often after short‑term antibiotics. (journals.lww.com)

• Steroids and 5‑ASA do not heal fistulas. Mesalamine and prednisone are not effective for this purpose. (journals.lww.com)

• Nonhealing or long‑standing fistulas carry a small cancer risk, so new or changing symptoms need reevaluation. (academic.oup.com)

• Skin tags rarely require removal, and excision should be avoided during active disease. (pmc.ncbi.nlm.nih.gov)

How perianal disease is evaluated

• History and exam focus on pain, drainage, continence, and rectal bleeding. A digital rectal exam and anoscopy look for internal openings and rectal inflammation.

• Pelvic MRI is the imaging test of choice. It shows fistula paths, abscesses, and relation to the sphincter muscles. Endoanal ultrasound can help when MRI is not available. (pubmed.ncbi.nlm.nih.gov)

• Many cases need an exam under anesthesia. The surgeon drains any abscess, identifies tracts, and often places a seton, a soft loop that keeps the tract open to drain. (journals.lww.com)

Clinicians classify fistulas as simple or complex. Simple usually means a low single tract without abscess. Complex means higher tracts, multiple openings, associated abscess, or rectovaginal involvement. This guides whether fistulotomy is safe, or if seton plus medical therapy is needed. (pmc.ncbi.nlm.nih.gov)

First priority: treat abscesses

An abscess needs prompt drainage. Antibiotics alone are not enough. Drainage comes before starting or escalating immunosuppression. Typical antibiotics are metronidazole and ciprofloxacin as short‑term helpers, especially with sepsis, but they do not replace drainage. (journals.lww.com)

Medical therapy to close fistulas

• Anti‑TNF therapy, especially infliximab, has the strongest evidence for inducing and maintaining fistula closure. Early short‑term antibiotics can improve response. Adalimumab also helps, though data are less robust. (journals.lww.com)

• Drug levels matter. Higher maintenance levels of infliximab and adalimumab are linked with better fistula healing. Teams often use therapeutic drug monitoring to reach targets. (pubmed.ncbi.nlm.nih.gov)

• Other options: vedolizumab and ustekinumab can help some people, often after anti‑TNF. Upadacitinib has emerging data, but evidence is limited and mixed across guidelines. (journals.lww.com)

• Thiopurines may support maintenance in select cases. Tacrolimus can be used short term for cutaneous or perianal fistulas when other options are limited. (journals.lww.com)

Surgery and timing

Seton placement is common in complex disease. It controls sepsis and preserves continence while medicines work. Seton alone is usually not a definitive strategy. When the tract is quiet and rectal inflammation is controlled, the seton can be removed, or the surgeon may attempt closure. (academic.oup.com)

Choice of procedure depends on anatomy and rectal health:
- Simple, low tracts without active proctitis may be treated with fistulotomy.
- For complex tracts, options include endorectal advancement flap or LIFT. Coordination with anti‑TNF increases success and lowers relapse. (journals.lww.com)

Severe, refractory disease may require temporary diversion. Proctectomy is reserved for the most resistant cases. Long‑term success of diversion alone is low, so it is used selectively. (journals.lww.com)

Skin tags, fissures, and strictures

Perianal skin tags are common. Most do not need surgery. Excision during active disease can heal poorly. If tags cause hygiene problems, careful removal can be considered in deep remission by an experienced surgeon. Anal fissures and strictures should be managed with medical control of rectal inflammation, with procedures only in select cases. (pmc.ncbi.nlm.nih.gov)

Living with perianal disease: practical care

Warm sitz baths, gentle cleansing, barrier creams, and absorbent pads can improve comfort. Ask how to care for a seton and how long it will stay in place. Seek urgent care for fever, rapidly worsening pain, swelling, or new drainage, which can signal a new abscess. (crohnscolitisfoundation.org)

Monitoring and targets

Teams aim for no drainage with gentle pressure, improved quality of life, and healed rectal mucosa. MRI helps track healing, although scarring and slow radiologic change are common. Combined surgical closure plus biologic therapy achieves deeper MRI healing than medicine alone in some series. Drug‑level–guided dosing is often used to sustain remission. (academic.oup.com)

What about stem cell injections

Darvadstrocel, an adipose‑derived stem cell product, is not approved by the U.S. Food and Drug Administration as of November 2025. Its European authorization was withdrawn after a large trial failed to confirm benefit. (ema.europa.eu)

Quick reference: common treatments

FAQs

What counts as “healed”

Clinically, no drainage with gentle pressure. Many teams also use MRI to confirm deeper healing, since tracts can look better on the outside before they are quiet inside. (academic.oup.com)

How long does a seton stay in

It varies. Many remain for weeks to months while infection settles and medicines work. Removal or definitive repair is timed after clinical response. (academic.oup.com)

When should cancer be considered

A small number of people with long‑standing perianal Crohn’s develop cancer in a fistula. New pain, bleeding, growth, or nonhealing drainage should prompt evaluation, often with biopsy under anesthesia. (academic.oup.com)