When hard faecolith is passed through anal canal with straining;due to more dilatation,stretching and rubbing of mucosa of anal canal,cracks develop which get infected and cause severe pain while passing motion associated with little bleed.Prolonged history of diarrhoea may also cause cracks,inflammation and anal fissure.It is called acute fissure in ano.It is different entity from piles which are dilated veins in anal canal which cause intermittent fresh bleed during act of defecation. Haemoglobin fall is significant with piles than fissure but mostly piles are painless except when internal haemorrhoids are associated with external haemorrhoids which may get infected or may have thrombosis.
In majority of cases of acute fissure in ano,medical treatment is successful but complete healing of fissure may need two to three weeks.
In very few cases surgical intervention is required when fissure leads to acute spasm of anal sphincter and person has excruciating pain with tremendous difficulty to pass stool.
