Anal fissure: Clinical sciences

Anal fissures are longitudinal tears in the anal mucosa under the dentate line. Since this region is innervated by somatic nerves, anal fissures are often quite painful. Now, there are two types of anal fissures: typical or primary fissures, caused by local trauma, and atypical or secondary fissures, which are associated with some other condition, such as Crohn disease.

Alright, the first step when approaching a patient with signs and symptoms suggestive of an anal fissure is to obtain a focused history and physical examination.

Patients with typical, or primary, anal fissures usually report severe anal pain that might be present at rest, but worsens during defecation and may persist for several hours. Additionally, they might report anal bleeding or hematochezia. History might reveal local trauma, such as constipation and passing large, hard stools.

On physical exam, typical anal fissures usually present as superficial lacerations located in the posterior midline. Less commonly, they can be seen in the anterior midline, or in both the anterior and posterior midline.

Similarly, individuals with atypical or secondary anal fissures usually report anal bleeding and pain that’s present at rest but worsens during defecation. History typically reveals chronic, multiple, recurring, and non-healing fissures. On physical examination, you may see multiple wide, deep fissures that are healing poorly.

In contrast to typical fissures, atypical fissures are found in locations other than the midline, often the lateral region. Additionally, a patient might have perianal skin tags, which are remnants from previous bouts of inflammation. In some cases, perianal skin tags can become edematous and painful.

Alright, now that you’ve obtained a history and physical examination, let’s move on to the management of typical anal fissure. Individuals with typical anal fissures are initially treated with supportive care, which includes stool softeners, sitz baths, and a fiber-rich diet, with or without topical analgesics. If this initial treatment doesn’t help, you should continue supportive care and add topical calcium channel blockers like nifedipine or topical nitrates. These can help relax the smooth muscles of the internal anal sphincter and promote healing.