Anal Abscess​


An anal abscess is a collection of pus which forms near the anus, mainly due to infection from the small anal glands. One type of abscess is a perirectal abscess, which is a collection of pus that forms in the deep tissue around the anus. But the most common type of abscess is a perianal abscess which is a shallower and more serious case of pus under the skin surrounding the anus, which often appears as a painful boil-like swelling. This swelling may seem red in colour and feel warm to the touch. In some instances, a perianal abscess may appear from infected skin that is adjacent to the anus. Both perirectal and perianal abscesses are sometimes referred to as anal abscesses. 

Possible causes of anal abscesses include:

  • Infection of an anal fissure​​– this is a small superficial tear in the skin of your anal canal
  • Infections transmitted sexually 
  • Obstructed anal glands. 

Amongst others, some risk factors that increase the chances of developing perianal accesses include diabetes, inflammatory bowel diseases (such as Crohn’s disease​) and certain medications. You should seek medical attention of either form of abscess; however a perirectal abscess is considered the more severe form of infection. A delay in treatment has the potential to worsen condition and unavoidable complications, eventually developing into a serious systematic infection.

Common symptoms of superficial or deeper anal abscesses include:

  • Pain – you may experience a constant, throbbing pain, in the anal or buttocks area which tends to get worse while sitting down
  • Skin irritation – the skin around the anus may be irritated, swollen, red and feel tender
  • A lump – near the anal area 
  • Discharge of pus or bleeding 
  • Constipation – you may experience constipation, or pain or discomfort during bowel movements 
  • Fever 
  • Chills 
  • Fatigue 

However, in some cases a fever is the only indicator of deep anal abscesses. 

If you suspect that you may have anal abscess, you should seek the advice of a healthcare professional working with the GI and Surgery Service Line at The Aga Khan University Hospital. However, you should go to 24/7 Emergency and Acute Care Services at The Aga Khan University Hospital immediately if you are experiencing any of these symptoms:

  • High fever 

  • Shaking chills

  • Severe anal or rectal pain

  • An inability to have a bowel movement or a very painful bowel movement 

  • Persistent vomiting 

  • Any other concerning symptoms or indicators that suggest an emergency situation.  

​Your time with your doctor maybe limited, so make sure to prepare for your visit beforehand. Here are some tips to help get you started.

If you visit the doctor at the GI and Surgery Service Line at The Aga Khan University Hospital with symptoms of a perirectal or perianal abscess, they will usually begin with questions about the symptoms you are experiencing, and examine your medical records and history. They will then conduct a physical examination, and check the area for any nodules. This is nothing to be embarrassed about, and is quite essential for a proper diagnosis. They will also check to see if there is any observable swelling, redness or pain in the anal area. However, in some instances there may not be any visible indicators of an abscess on the surface of your skin that surrounds your anus. Your doctor may need to perform further tests in order to make a proper diagnosis. This could include:

  • A digital rectal examination 

  • Anoscope – this will help to examine the inside of your anal canal and lower rectum 

  • Blood tests – these will help rule out any other contributing factors that may be causing the negative symptoms of anal abscesses

  • Magnetic Resonance Imaging (MRI), ultrasound or Computerized Tomography (CT) scan – these will help to get a better look for an accurate diagnosis

The most common form of treatment for anal abscesses is surgical incisions and drainage. Your doctor will drain the pus from the infected area after anaesthesia then relieving the contents, allowing the tissue to start to heal properly. In some cases, a catheter may be used for few days in order to make sure the abscess drains completely.  Your doctor may prescribe antibiotics after the surgery in order to treat infection or as support for those with a compromised immune system.  This is usually successful in alleviating the symptoms. However, many patients with anal abscesses will develop a complication known as a fistula, especially if it is left untreated for too long. A fistula is when a small tunnel forms between the site of your abscess and your skin. Sometimes, fistulas cause persistent drainage, which can lead to recurrent anal abscesses. Surgery is required for most cases of anal fistulas.  

​Please click here for some guidelines on “what to do before your surgery”

Please click here for some guidelines on “what to do on the day of your surgery”

The outcome of surgery is usually positive, especially with prompt treatment. However, as with any surgical procedure, here are some potential risks and complications:

  • Problems associated with anaesthesia - such as pain, bloating, gas or diarrhoea. 

  • Systemic infection 

  • Recurrence 

Please click here for some guidelines on “what to do after your surgery”

The Aga Khan University Hospital offers various support services to help with managing or recovering from the disease or condition. These include but are not limited to nutrition, physiotherapy, rehabilitation, specialized clinics and some patient support groups. Your doctor or nurse will advise you accordingly.

The Aga Khan University Hospital offers financial assistance to those who are in need and fulfil the eligibility criteria. For further information, you can contact the Patient Welfare Department. You can find the contact number of the Patient Welfare Department in the ‘Important Numbers’ section on the website homepage.

​The financial counselling staff is available during office hours, at the main PBSD (Patient Business Services Department), to answer your financial queries on treatments’ costs and authorize admissions on partial deposit as per hospital policies allow. The financial counsellor in the emergency room is open 24/7. You can find the contact number of the Patient Business Services in the ‘Important Numbers’ section on the website homepage.

​Your doctor and or nurse will give you specific instructions about the prescribed medication. Please ensure that you take or use the prescribed medicine as advised. It can be dangerous to your health if you self-prescribe. Please inform the doctor or nurse beforehand if you have experienced any adverse reactions to any medications in the past. If you experience any symptoms of drug poisoning, overdose or severe reaction please contact the Pharmacy Service at The Aga Khan University Hospital immediately. You can find the contact number of the Pharmacy Services in the ‘Important Numbers’ section on the website homepage.



The information provided on our website is for educational purposes and not intended to be a substitute for medical advice, diagnosis or treatment. You should always seek the advice of your doctor or other healthcare professional provider. ​