At a glance
“What does it look like?” is one of the most common questions people have when they suspect they have an anal fissure. The answer is nuanced — fissures can look different depending on whether they are acute or chronic, and many fissures are not visible from outside the body.
This guide describes what clinicians look for when examining a fissure, what the visible features mean, and why self-diagnosis based on appearance alone has significant limitations.
What a fissure actually is
An anal fissure is a tear or crack in the lining (mucosa) of the anal canal. The anal canal is the short passage between the rectum and the outside. Fissures most commonly occur at the posterior midline — the back of the anal canal — though they can occur in other positions.
The tear involves the surface lining and sometimes the tissue beneath it. It is essentially a wound in a location that is constantly exposed to the trauma of bowel movements, which is why healing can be difficult.
Acute fissure appearance
An acute fissure — one that is recent, typically less than six to eight weeks old — has a relatively simple appearance:
- A fresh tear in the anal lining, similar in appearance to a paper cut
- Shallow — involving the surface layers
- Clean edges — not raised or thickened
- Surrounding redness — inflammation around the tear
- Possibly some visible blood at the site
- No associated skin tags or thickened tissue
Acute fissures can be difficult to see from the outside because they are often within the anal canal rather than at the very edge.
Chronic fissure appearance
A chronic fissure — one that has been present for more than six to eight weeks — develops additional features:
- A deeper tear that extends further into the tissue
- Raised, thickened edges — the body’s response to ongoing inflammation
- Exposed muscle fibres — the internal sphincter may be visible at the base of the fissure
- A sentinel pile — a small skin tag at the external (lower) end of the fissure
- A hypertrophied papilla — thickened tissue at the internal (upper) end
- Pale or fibrous tissue at the base — scar-like tissue indicating chronicity
These features together are sometimes called the “triad of chronicity” — the deep fissure, the sentinel pile, and the hypertrophied papilla. Their presence helps clinicians determine that a fissure is chronic rather than acute, which influences treatment decisions.
What you might see or feel
People describe their own observations:
What people see
- A small flap of skin at the anal margin — often a sentinel pile
- Redness or raw-looking tissue
- A crack or split in the skin, sometimes visible when the area is gently spread
- Blood on the tissue or toilet paper
What people feel
- A tender area that is painful to touch
- A small lump — typically a sentinel pile or swollen tissue
- A sensation of a cut or tear during bowel movements
- Burning or stinging at a specific point
The limits of self-assessment
People consistently describe the difficulty of self-examination:
- The area is hard to see, even with a mirror
- Anxiety makes the examination uncomfortable
- It is nearly impossible to distinguish between a fissure, a haemorrhoid, and other conditions by feel or sight alone
- Internal fissures are not visible externally
Fissure vs other conditions
Several other conditions can look or feel similar to a fissure:
Haemorrhoids
- Swollen blood vessels that may protrude from the anus
- Can cause similar symptoms — pain, bleeding, lumps
- External haemorrhoids are typically more rounded and blue-purple when thrombosed
Perianal abscess
- A painful, swollen lump
- Usually more significantly swollen than a sentinel pile
- May feel warm to touch
- Often associated with fever
Skin tags
- Soft flaps of skin at the anal margin
- Can exist independently of fissures
- Generally painless unless irritated
Anal fistula
- An abnormal tunnel that may produce discharge from an external opening
- Can cause a small opening visible on the skin near the anus
A clinician can distinguish between these conditions with an examination.
The clinical examination
If you suspect a fissure, a clinical examination typically involves:
- A visual inspection of the perianal area — the clinician gently parts the buttocks to visualise the anal margin
- Identification of features — the fissure itself, any sentinel pile, redness, or other findings
- A digital examination — a gloved finger examination, though this may be deferred if the area is too painful
- Proctoscopy — a small instrument to view inside the anal canal, sometimes deferred until treatment has reduced pain
The examination is brief. Most fissures can be diagnosed with a visual examination alone.
Why appearance matters
The appearance of a fissure provides clinical information:
- Acute vs chronic: Determines the treatment approach
- Location: Posterior midline is typical; lateral fissures may prompt investigation for other conditions
- Depth: Deeper fissures may be less likely to respond to conservative treatment
- Associated features: Sentinel piles and papillae indicate chronicity
- Other findings: The examination may reveal other conditions contributing to symptoms
When to get it checked
Any persistent anal symptoms — pain, bleeding, lumps, or discharge — are worth having assessed by a clinician. Self-diagnosis is unreliable for conditions in this area, and a clinical examination provides:
- Confirmation of the diagnosis
- Assessment of severity and chronicity
- A treatment plan appropriate for the specific findings
- Exclusion of other conditions
- Peace of mind