What causes a perianal abscess or fistula?
It is not known why some people develop perianal abscesses and fistulas in the average population. Crohn's disease is a condition that can present with multiple or recurrent perianal abscesses or fistulas and should be considered as an underlying diagnosis in people who have recurrent or severe fistula disease.
Perianal abscess treatment options
The treatment for a perianal abscess is incision and drainage of the abscess. This is usually done by making a small cut in the skin overlying the abscess and draining the pus. Simple drainage is enough to treat the infection. Placement of a drain may be needed to help continue drainage of pus as the abscess cavity heals.
Half of the time, a fistula tract will form. This means that the site of drainage will not completely close and will continue to drain stool from the opening where the abscess was drained.
Often a closer look at this tract is needed via an examination under anesthesia (EUA). At the time of EUA, the surgeon can identify the opening on the skin and find the connection to the inside of the anal canal. Once this is identified the surgeon will be able to see how much muscle the fistula tunnel goes through. A fistula can cross the anal sphincter muscle (trans-sphincteric), run above the sphincter muscle (supra-sphincteric), or may be superficial to the sphincter muscle (extra-sphincteric). This will determine treatment options.
If the fistula goes through a small amount or no muscle, a "fistulotomy" can be performed where the fistula is cut open and allow it to heal. This the most effective method of removing a fistula; however it carries a small risk of causing loss of bowel control from injury to the sphincter muscle.
If too much muscle is involved or if a person is at high risk for developing loss of bowel control, a fistulotomy is not recommended. A number of procedures are available in this case and your surgeon will discuss the risks and benefits of each when developing your treatment plan.