Anal fissures are frequent, simple to diagnose, and often overlooked.
A fissure is a longitudinal tear/wound/ulceration
between the dentate line and the anal verge, typically located in
the midline, associated with high anal sphincter tone. Risk factors:
constipation, chronic diarrhea (idiopathic, IBD, post–gastric
bypass), but fissure may also occur with normal bowel movements.
- • Acute fissure is defined as new onset, no
signs of chronicity, typically related to identifiable acute episode
of constipation or diarrhea.
- • Chronic fissure is defined as either > 3 months
of symptoms or morphologic signs of chronicity (elevated/indurated
wound edges, exposed sphincter muscle, sentinel skin tag, hypertrophic
Complications are rare: development of a perirectal fistula/abscess,
chronic pain (even if fissure healed), ie, anismus.
Pathophysiology: acute or chronic stress/trauma to the
anal canal (constipation, diarrhea) results in superficial tear;
acute fissure will heal in 40–60% with appropriate
improved stool management, or may turn into chronic anal fissure
and result in a vicious circle: increasing sphincter tone, hypertonicity
of internal anal sphincter muscle (resting tone) → fissure
hiding between anal canal folding such that it cannot clean out → pain → increased
sphincter spasm → etc.
Treatment of fissure aims at normalizing stool regularity and
decreasing sphincter tone.
Exact prevalence and incidence are unknown (referral bias); in
a specialist clinic, 3–5% of patients have a fissure
as presenting symptom. More common in young and middle-aged adult patients;
most frequent cause of rectal bleeding in children.
Patients often present with “painful hemorrhoids” as
they feel the sentinel skin tag and notice the pain during and after
Pain: typically post defecation, varying degrees, ranging from
mild itching to discomfort to massive excruciating pain periods.
But an estimated 10% of patients do not complain of pain,
or they just have pruritus or mild discomfort.
Duration of pain: typically during and post bowel movements,
occasionally several hours thereafter, or permanent/constant
Bleeding: acute fissure—sometimes significant bright
red bleeding; chronic fissure—more often just traces of
blood on toilet paper. Severe hemorrhage or anemia unlikely related
Lump: “irritated” external hemorrhoids (sentinel
skin tag), but absence of dynamic protrusion during bowel movement.
Pain: thrombosed external hemorrhoid, abscess, levator ani spasm,
HIV-associated ulcer: HIV infection+; ulceration: often
in the same location and/or eccentric; sphincter tone typically
not increased, or even decreased.
Crohn disease: anal symptoms may be the only manifestation or
be associated with other signs/locations of active Crohn
Perirectal fistula/abscess: particularly horseshoe fistula
characteristically originates from posterior midline.
Tuberculosis: clinical suspicion, atypical presentation, associated
pulmonary symptoms, positive PPD test.