Perianal Abscess

What is Perianal Abscess?

A perianal abscess is a cavity pus-filled that forms around the anal canal. Most of the time this is caused by an accumulation of common bacteria that form a pocket of pus. Abscesses can form near or within the anus or develop much higher up in the rectum itself. While an abscess can form spontaneously without an apparent reason, it is also commonly associated with common gastrointestinal diseases. 

What are the symptoms? 

Perianal abscesses may present dull and stabbing pain in the anus or in the rectum, often accompanied by a perianal lump, which may or may not ooze some pus. The lump is usually a palpable mass, tender on palpation. Patients may also experience fever, fatigue, changes in bowel habit, rectal discharge and bleeding. 

If left untreated, a perianal abscess can lead to the development of an anal fistula.

What are the causes? 

An anorectal abscess can develop due to the overgrowth of bacteria which are common in the digestive tract and perianal skin. While anyone can get an anorectal abscess, there are a number of conditions that can increase the risk to develop these abscesses. These include Inflammatory bowel diseases (IBD), HIV and other forms of immune suppression, diabetes, anal intercourse, chemotherapy, chronic or severe constipation or diarrhoea. 

How can a perianal abscess be diagnosed?

Most anorectal abscesses are diagnosed based on medical evidence: history and a physical examination. It is important to exclude that the abscess is communicating with the anal canal and this can be excluded only with a full examination and a lower gastrointestinal endoscopic test. Sometimes an endoanal ultrasound scan or an MRI pelvis is recommended. 

How do we treat perianal abscess? 

Anorectal abscesses sometimes may go away on their own or resolve completely with antibiotics therapy. However, in most cases a surgical incision of the abscess is required. This can be performed either in clinic under local anaesthesia or in a safer environment under general anaesthesia, depending on many factors. If the abscess is especially deep or situated high in the rectum, the procedure needs to be performed in a hospital under general anaesthesia. The drainage in itself normally provides an almost immediate relief. While there may be some pain after the procedure, the wound can take a few days to heal.