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

Perianal Crohn’s disease affects the area around the anus and rectum. It can cause fistulas (abnormal tunnels), abscesses (pockets of infection), fissures, skin tags, and strictures. Around 1 in 5 people with Crohn’s develop perianal disease within 10 years, and it is linked with more severe illness and lower quality of life. Effective care usually combines advanced medical therapy with careful, often repeated, surgical procedures. (pubmed.ncbi.nlm.nih.gov)

Key Takeaways

• Perianal Crohn’s includes fistulas, abscesses, ulcers, fissures, strictures, and skin tags, often in people with rectal or distal colonic Crohn’s. (pubmed.ncbi.nlm.nih.gov)

• Evaluation usually includes gentle examination, pelvic MRI or anal ultrasound, and often an exam under anesthesia by a colorectal surgeon. (pmc.ncbi.nlm.nih.gov)

• Abscesses are surgical emergencies that need prompt drainage; antibiotics alone are not enough. (pmc.ncbi.nlm.nih.gov)

• Fistulas are usually managed with drainage (often a seton) plus medical therapy, most often biologics such as infliximab or adalimumab, sometimes with short-term antibiotics. (gastro.org)

• Skin tags are usually harmless markers of past inflammation and are removed only when necessary and when Crohn’s is well controlled. (academic.oup.com)

• Best outcomes come from a multidisciplinary team and from treating both the perianal problem and the underlying intestinal Crohn’s at the same time. (pmc.ncbi.nlm.nih.gov)

What Is Perianal Crohn’s Disease?

Perianal Crohn’s disease means Crohn’s-related inflammation or damage affecting the anus and surrounding skin. Common problems include:

• Fistulas (abnormal tunnels from the anal canal or rectum to the skin or nearby organs)

• Abscesses (pockets of pus)

• Fissures (painful splits in the anal skin)

• Skin tags, ulcers, and strictures (narrowing) (pubmed.ncbi.nlm.nih.gov)

Perianal disease is more likely when Crohn’s involves the rectum or left side of the colon and is considered a more aggressive phenotype, with higher use of biologics and more perianal surgeries over time. (pmc.ncbi.nlm.nih.gov)

Living with perianal disease can be painful, embarrassing, and disruptive to work, intimacy, and daily life. That is why current care emphasizes early diagnosis, strong medical therapy, and close collaboration between gastroenterologists and colorectal surgeons. (academic.oup.com)

Common Perianal Problems in Crohn’s

Perianal fistulas

A fistula is an abnormal tunnel that connects the inside of the bowel to the skin near the anus or sometimes to another organ, such as the vagina or bladder. Symptoms can include:

• Persistent drainage of pus or stool

• Pain, swelling, or a lump near the anus

• Episodes of abscess formation and fever

Fistulas are often classified as simple (single, low tract, no abscess) or complex (multiple tracts, high through the sphincter, with abscesses or involving other organs). Most Crohn’s-related anal fistulas are complex and need both medical and surgical treatment. (pmc.ncbi.nlm.nih.gov)

Perianal abscesses

A perianal abscess is a painful, swollen pocket of infection. It may cause:

• Severe perianal pain

• Redness and warmth

• Fever or feeling unwell

Guidelines recommend urgent surgical drainage under anesthesia. Surgeons usually avoid aggressive fistula surgery during the acute infection. If there is an obvious fistula opening, they may place a loose seton to keep it draining, but do not lay it open. Antibiotics are used as a supplement, not a replacement, for drainage. (pmc.ncbi.nlm.nih.gov)

Skin tags and other non‑fistulizing lesions

Perianal skin tags are small or large flaps of skin around the anus. In Crohn’s, they can be thick, soft “elephant ear” tags or small sentinel tags that signal a fissure. They are usually painless but can trap stool, bleed, or cause hygiene problems. (academic.oup.com)

Most tags are observed rather than removed. Surgery is considered only when:

• Tags are clearly causing symptoms, and

• Rectal Crohn’s is well controlled, to reduce the risk of poor wound healing. (academic.oup.com)

Other non‑fistulizing lesions include ulcers and strictures, which often improve when the underlying Crohn’s is treated with systemic therapy like biologics. (academic.oup.com)

How Perianal Crohn’s Is Evaluated

Clinical examination

Evaluation usually starts with:

• A careful history of pain, drainage, bleeding, continence, prior abscesses or surgeries, and impact on daily life

• Inspection of the perianal skin

• A gentle digital rectal exam when tolerated

Because this area is sensitive, exams are often done slowly, sometimes with topical anesthetic or sedation if needed.

Imaging

Pelvic MRI is the preferred test for mapping fistula tracts, detecting hidden abscesses, and distinguishing simple from complex fistulas. Anal endoscopic ultrasound is another option, especially in experienced centers. (pmc.ncbi.nlm.nih.gov)

MRI findings help the team plan surgery, choose where to place setons, and monitor response to treatments such as biologics.

Exam under anesthesia (EUA)

For complex or painful disease, a colorectal surgeon often performs an exam under anesthesia. This allows:

• Full inspection of the anal canal and rectum

• Drainage of any abscesses

• Placement of one or more loose setons through fistula tracts

EUA is commonly combined with imaging results to give the most accurate map of the perianal disease. (pmc.ncbi.nlm.nih.gov)

At the same time, clinicians usually review how active the intestinal Crohn’s is, because untreated rectal inflammation worsens healing and limits surgical options. (pmc.ncbi.nlm.nih.gov)

Treatment Principles: Combining Medical and Surgical Care

Perianal Crohn’s care follows a few key principles:

1. Control sepsis first (drain abscesses, secure drainage with setons).

2. Protect continence by avoiding aggressive cutting of sphincter muscle.

3. Treat the underlying Crohn’s with effective systemic therapy.

4. Use staged surgery for closure or reconstruction once inflammation is controlled. (pmc.ncbi.nlm.nih.gov)

Treating abscesses

• Prompt incision and drainage in the operating room

• Culture-directed antibiotics when there is fever or systemic illness

• Assessment for fistula and possible loose seton placement if a tract is obvious, without attempting definitive repair at that time (pmc.ncbi.nlm.nih.gov)

Managing fistulas: setons and biologics

A seton is a soft loop of suture or rubber passed through the fistula and tied outside. It:

• Keeps the tract open so it drains

• Prevents recurrent abscesses while medical therapy works

Evidence and guidelines support combining seton drainage with biologic therapy, especially anti‑TNF agents such as infliximab or adalimumab. (pubmed.ncbi.nlm.nih.gov)

The American Gastroenterological Association recommends:

• Infliximab for induction and maintenance of fistula remission in active perianal Crohn’s

• Adalimumab, ustekinumab, or vedolizumab as alternatives

• Adding a short course of antibiotics (often ciprofloxacin and/or metronidazole) to biologics for better short‑term fistula response

• Avoiding antibiotics alone for fistulas without abscess, because they rarely produce lasting remission (gastro.org)

Many patients need long‑term biologic therapy to keep fistulas quiet. Setons are usually left in place for months and removed once imaging and symptoms suggest healing, although the ideal timing is still debated. (pmc.ncbi.nlm.nih.gov)

Definitive surgical options

When sepsis is controlled and Crohn’s is well treated, surgeons may consider:

• Fistulotomy for carefully selected simple, low fistulas

• Mucosal advancement flap or LIFT (ligation of the intersphincteric fistula tract)

• Plugs or glues in selected cases

The PISA randomized trial suggested chronic seton drainage alone led to more re‑interventions than anti‑TNF therapy or surgical closure after short‑course anti‑TNF, so setons are usually not used as the only long‑term treatment. (pubmed.ncbi.nlm.nih.gov)

For severe, refractory disease with badly damaged rectum, options may include a temporary diverting stoma or, rarely, proctectomy with permanent stoma. These decisions are major and typically made in high‑volume IBD centers. (pmc.ncbi.nlm.nih.gov)

Managing skin tags and fissures

• Skin tags are usually left alone unless they interfere with hygiene, cause pain, or hide other lesions. Excision is timed for periods of well‑controlled disease to improve healing. (academic.oup.com)

• Anal fissures are treated by softening stools, reducing diarrhea, and controlling inflammation. Topical medicines or botulinum toxin may be used, though high‑quality data in Crohn’s are limited. (pmc.ncbi.nlm.nih.gov)

At‑a‑Glance: Problems and Typical Management

(pmc.ncbi.nlm.nih.gov)

Living With Perianal Crohn’s: Ongoing Care

Long‑term management usually includes:

• Regular follow‑up with both gastroenterology and colorectal surgery

• Tracking of symptoms such as pain, drainage, fevers, continence, and sexual function

• Adjustments in biologic dosing or switching therapies if fistulas re‑activate

• Careful perianal hygiene, often with warm sitz baths and barrier creams, adapted to individual tolerance

Smoking is a known risk factor for more aggressive Crohn’s disease overall and is linked in several studies to higher rates of complications and surgery, so most IBD programs strongly encourage smoking cessation. (pmc.ncbi.nlm.nih.gov)

FAQs

Can perianal Crohn’s be the first sign of Crohn’s disease?

Yes. In some people, a perianal fistula or abscess appears years before intestinal Crohn’s is diagnosed. Studies suggest that a significant minority of Crohn’s patients present this way, which is why persistent or recurrent perianal problems often prompt a search for underlying IBD. (pubmed.ncbi.nlm.nih.gov)

Do perianal fistulas ever heal completely?

Many fistulas improve or close with a combination of drainage and modern biologic therapy, but recurrence is common and some tracts remain “quiet” rather than fully closed. Long‑term control, not guaranteed cure, is usually the realistic goal, especially for complex fistulas. (pmc.ncbi.nlm.nih.gov)

Are perianal skin tags dangerous?

Most Crohn’s‑related perianal skin tags are benign and do not turn into cancer. Their main issues are discomfort and hygiene. They can also signal other hidden perianal disease, so clinicians usually examine carefully and use imaging if there are symptoms such as pain or drainage. (academic.oup.com)

When is a stoma considered for perianal Crohn’s?

A temporary diverting stoma or permanent stoma is considered when there is severe, refractory perianal disease, often with uncontrolled rectal inflammation, repeated sepsis, or major damage to the anal sphincter. These decisions weigh quality of life, continence, and the safety of further local procedures. (pmc.ncbi.nlm.nih.gov)