Anal fissure

Information has been excerpted from VisualDx clinical decision support system as a public health service. Additional information, including symptoms, diagnostic pearls, differential diagnosis, best tests, and management pearls, is available in VisualDx.


Anal fissures are chronic tears in the mucosa of the anal canal and are a very common cause of bright red blood associated with bowel movements. Fissures should be suspected if a patient complains of long-lasting pain or burning during and after defecation. The pain associated with fissures can be so severe it leads to constipation. This in turn can lead to more firm stool and worsening of the fissure.

Anal fissures are common in infancy and most often occur in children aged 6–24 months. However, the overall incidence of the problem is not well reported. The incidence of anal fissures decreases rapidly with age and is much less common among school-aged children than infants.

Most patients have only one posterior midline anal fissure. Lateral fissures have been associated with trauma, sexually transmitted infections (STIs), and other gastrointestinal disorders such as inflammatory bowel disease. Multiple fissures of the anal canal can be detected after abuse or in patients with significant underlying medical problems.

Careful history and physical examination usually confirm the diagnosis. Parents may report a history of painful constipation and may have noticed red blood associated with bowel movements. It is extremely important to ask about associated fever, rash, oral or skin lesions, diarrhea, abdominal pain, and weight loss, as systemic diseases may manifest with anal lesions. The pain associated with anal fissures is an important psychological feature to evaluate and address.

Anal fissures, constipation, and abnormal anal dilatation may be seen in sexually abused children, although they are not diagnostic of abuse. Most sexually abused children do not have abnormal physical findings.

Look For

Fissures typically appear as short linear breaks or linear erosions in the anal mucosa. As the lesions become more chronic, there may be associated thickening of the border of the fissure.

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