Diagnosis is by case history and physical exam.
Careful spreading of the buttocks normally allows visualization of the fissure.
If a fissure is visualized, anoscopy is not indicated.
If this maneuver does not allow visualization, anoscopy with a small caliber
anoscope that is lubricated with lidocaine ointment,
gentle palpation with a lubricated finger,
or endoscopy may be required for diagnosis.
Chronic fissures may give rise to an external skin-tag called a
sentinel pile inferior to the fissure,
an enlarged papilla superior to the fissure,
and white fibrous scar tissue along the path of the fissure.
Muscle fibers may be visible in the trough of the fissure.
Fissures are normally long and narrow with sharply demarcated borders.
Other shapes should raise suspicion of other causes (see DDX).
The most common locations of fissures due to physical abrasion are the
posterior and anterior midlines, and occur singly.
Multiple fissures or fissures located in other areas
should raise suspicion of other causes (see DDX).