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Anal Fissures

 

Anal fissure

This guideline applies to situations where the diagnosis of anal fissure is likely or confirmed. If diagnostic uncertainty, please see the guideline on "Undiagnosed Rectal Bleeding".

 

Aetiology

Anal fissures can be:

  • Acute: < 6wks
     
  • Chronic: > 6wks; a “sentinel tag” may be seen
     
  • Primary: Believed to be due to spasm after defaecatory trauma and poor perfusion/poor healing.
     
  • Secondary: Due to underlying cause, e.g. IBD, sexually transmitted infections, sexual abuse, rectal malignancy, drugs (nicorandil is a potential cause of unusual perianal fissuring and ulceration) and pelvic floor disorders.

Primary fissures are located at the posterior and anterior anal midlines (90% females, 99% males) and are benign. Secondary fissures are often located outside of the midline, and if associated with skin changes or inflamed skin tags should raise clinical suspicion of IBD (though is a very rare initial IBD presentation).

 

Alternative causes for acute anal pain

Acute anal pain requires a face to face consultation for examination to exclude perianal sepsis or malignancy. In extreme circumstances admission may be required.

  • Acute perianal sepsis: usually presents with obvious swelling and tenderness starting on one side of the anus but can spread to the other side (horseshoe pattern). Sometimes it may not be obvious from the outside (if there is an intersphincteric abscess). Patients find PR examination unbearable and have constant pain with recent onset. There may be fever, tachycardia, deranged BG in diabetics. Patients with perianal sepsis should be admitted.
     
  • Malignancy: is rarely painful unless it is very advanced (and very obvious). Anal malignancy typically is noticed due to bleeding or irritation and may be an ulcer or an ‘odd uneven anal lesion’ akin to a bizarre skin tag.
     
  • Thombosed haemorrhoids: are a common cause of acute anal pain and evident externally.
     


Clinical features of anal fissure

Anal pain on defaecation, which typically feels like passing razor blades and often followed by throbbing pain for an hour or two. May be accompanied by blood on toilet paper, not usually high volume.

 

Ask about:

  • Bowel habit – managing constipation may reduce the chance of recurrence, diarrhoea may point towards IBD
     
  • Red flag symptoms – change in bowel habit, blood mixed into stools <LINK to colorectal 2WW>
     
  • Family history- IBD, colorectal disease

 

Examine:

  • Left lateral position with a good light; part the skin of the anal margin. Some fissures are difficult to see particularly in obese patients. Being unable to see a fissure does not exclude it when there is a typical history and anal spasm
     

Primary care management prior to referral

Almost half of acute anal fissures will resolve with conservative measures. The aim is to soften the stool and to use either GTN or Diltiazem topically, to reduce spasm and promote healing.

  • Dietary and lifestyle advice
    • Increase fluid (6-8 glasses/day) and insoluble fibre intake (18-30g/day)
    • Discourage straining
    • Regular exercise
    • Feet-up position
    • Warm baths
    • Good perianal hygiene, keep area clean and dry, minimise use of perfumed toiletries and avoid wet wipes of any sort
  • Consider laxatives
    • Bulk-forming (adults) or osmotic (children)
  • Simple oral analgesia
    • Paracetamol/NSAIDS (avoid codeine as constipating)
  • Topical preparations for pain and symptom relief
    • Anaesthetic preparation, e.g. 1-2ml of lidocaine applied as required before passing a stool (max 14 days)
  • Topical preparations to promote healing
    • 0.4% GTN ointment (Rectogesic) or 2% Diltiazem hydrochloride (Anoheal)
    • These medicines are not analgesics, though may ease pain due to reducing spasm
    • Patients should apply a pea sized amount BD for 6wks, into the lower 1/3 of the anal canal; using a covered finger to minimise double dosage
    • Headaches are a common side effect and often settle within 4 days as the cardiovascular system adjusts

 

When to consider referral


RCHT 2WW Colorectal Form is available here

 

 Information required with referral

  • Patient’s symptoms
  • Findings of DRE (if it has been tolerable and done)
  • Details of prior therapeutic trials, including length of use of medications*

*Referrals will be cancelled if therapeutic trials are not of an appropriate period of time (6-8wks), unless over-riding concerns are detailed.


Clinics

All referrals will be initially triaged by the Colorectal Surgery team and patients will be reviewed accordingly.

 

Resources

https://patient.info/doctor/anal-fissure-pro

 

Page Review Information

Review Date                         14 April 2025

Next Review Date                 14 April 2027

GP Sifter                               Dr Laura Vines

Contributor                            Ms Melanie Feldman