An anal abscess is a painful pool of infected liquid (pus) near your back passage (rectum) or bottom (anus). An anal abscess is sometimes referred to as a perianal abscess and is also known as an anorectal abscess.
An anal abscess usually forms when an infection in one of the glands around your anus generates pus. The pus gathers in a cavity in the skin and develops into a painful abscess.
The most common type of anal abscess is a perianal abscess, which occurs near your anus and looks like a boil. Anal abscesses can occur in deeper tissue where they are less visible; however, this is less common than superficial anal abscesses.
Men are twice as likely as women to have anal abscesses, which are more common between age 20-60.
An anal abscess needs medical treatment to drain the pus, relieve pain and reduce the risk of further infection. Surgery is usually successful in treating anal abscesses.
Common symptoms of a superficial anal abscess include:
Common symptoms of a deeper anal abscess include:
If you think you have an anal abscess, see your GP as soon as possible. They’ll ask about your symptoms, and your general health, including any history of bowel conditions.
They’ll examine your anus and rectum to check for pain, redness or swelling, as well as for a visible anal abscess or anal fistula (perianal abscess fistula). About one in two people with an anal abscess develops an anal fistula, a tunnel between your anus and rectum. Sometimes the fistula persistently leaks pus. However, if the opening of the tunnel closes, you may instead have recurring anal abscesses. Surgery is needed to treat anal fistulas.
If there are no visible signs of an anal abscess on the surface of your skin, your GP may use an endoscope (a thin telescope-like tube with a camera on the end) to look inside your anal canal and rectum. If an anal abscess can't be detected by a physical examination, your GP may refer you for an MRI scan or an ultrasound scan.
Your GP will check for conditions that can cause similar symptoms as an anal abscess. You may therefore be referred for further investigations to check for:
Your GP may also refer you to a colorectal surgeon.
The risk of having an anal abscess is higher if you have:
Certain medical treatments can also increase your risk of anal abscesses, such as:
Children and toddlers who have a history of constipation are more likely to have anal fissures, which increases their risk of developing anal abscesses.
In infants and toddlers, frequent nappy changes can lower their risk of developing anal fistulas and perianal abscesses.
An anal abscess must be surgically drained, as quickly as possible, ideally before it erupts. Your GP or consultant will drain your anal abscess, which can be done under a local or general anaesthetic — deep anal abscesses may need to be drained in a hospital under general anaesthetic while superficial anal abscesses can be drained under local anaesthetic. Drained abscesses do not usually need stitches and are left open to heal.
Very large anal abscesses may need surgery and in some cases, a catheter (a flexible tube) will be inserted to ensure the abscess drains completely. If you have diabetes or a weakened immune system, you may stay in hospital for several days to check for infection developing.
Once your abscess is drained, your discomfort and pain should decrease as the pressure of the abscess is relieved. Your anal tissue can then heal. You may still experience some mild pain; your GP or consultant can prescribe you with pain relief and, if necessary, antibiotics.
Your doctor may recommend:
If you have an anal fistula and an anal abscess, surgery to correct both can be performed simultaneously. However, anal fistulas often develop four to six weeks after an abscess is drained, and sometimes several months or years later. Fistula surgery is therefore usually performed separately.
Complications after surgery for an anal abscess include:
There is currently not much known about how to effectively prevent anal abscesses. However, you can reduce your risk by:
Anal abscesses can cause complications but they are treatable.
Is a perianal abscess serious?
A perianal abscess can cause considerable discomfort and pain. If left untreated, the infection can worsen and cause an anal fistula to develop. Anal fistulas need surgery, which is a more involved procedure than draining a perianal abscess.
If you have a perianal abscess, see your GP to have it treated.
Can a perianal abscess heal on its own?
In almost all cases a perianal abscess will not heal on its own. It needs medical treatment to drain the pus, relieve your pain and reduce the risk of further infection. If you have a very large perianal abscess or you also have an anal fistula, you will most likely need surgery.
How long does perianal abscess take to heal?
This depends on the size of your abscess. In general, it will take at least several weeks for your abscess to completely heal.
What does perianal abscess look like?
Perianal abscesses appear as boil-like swellings near your anus.
Can I burst an abscess myself?
Do not burst an abscess yourself. This can spread the infection and cause greater harm. See your GP for treatment — this will usually involve draining your abscess while under local or general anaesthetic, depending on the size of your abscess and whether it is superficial or deep.
Can a perianal abscess spread?
Yes, a perianal abscess can spread around your anus and rectum, as well as deeper into the tissue surrounding your anus and rectum.