Tear in the mucosa of the anal canal, just inside the anal margin

Aetiology

• Usually due to passage of a constipated stool
• Multiple fissures may be due to Crohn’s disease

Clinical features

Symptoms

• Acute onset of severe anal pain usually following an episode of constipation
• Pain lasts for up to 30 mins after defecation
• Bright red rectal bleeding

Signs

• The fissure can be seen on external examination of the anus - usually in the midline posteriorly but may occasionally be anterior

Investigations

• Diagnosis is clinical and further investigation is only required if there are features of underlying pathology

Management

• Treatment usually involves dietary advice, an anesthetic cream and a stool softener
• Pharmacological sphincterotomy (GTN, diltiazem) may be used
• Chronic – lateral sphincterotomy, Botox injection