Anal sac disorders in dogs

Read our guide to understanding the oft-ignored anal sac disorder.

What are anal sacs and what is their role?

Anal sacs are two small sacs on either side of the anus and are lined with sweat glands that 

produce a fluid which has a foul smell.  They secrete this fluid produced by the anal glands naturally each time they poop. It is one of the ways dogs communicate with each other as they mark their territories because the fluid is a scent marker.

What are anal sac disorders in dogs?

There are different kinds of disorders that develop in the anal sacs: impaction, abscessation, and inflammation. Any one of these diseases or disorders are more common in small dogs such as Chihuahua or Toy Poodles. The larger breeds do not usually succumb to anal sac disorders. 

General causes of anal sac disorders:


This is one of the most common areas of concern. This happens when the fluid stored in the anal sacs do not get expressed naturally. This can lead to an infection in the anal sacs. It causes extreme discomfort in the dog.


Dogs with their anal sacs filled with fluid that is not expressed naturally develop an inflammation of the anal sacs. This is by way of bacterial growth and infection.


When the anal sacs do not secrete the fluid naturally, they need to be treated immediately. Or, they become infected, and can become abscessed. What this means is that the fluid retention in the anal sacs can build too high a pressure in the anal glands and can rupture. As the anal glands are impacted, this rupture happens through your dog’s skin. Surgery may be required to drain the fluid. 


This is an abnormal growth of cells that could be cancerous. It may be benign or become malignant over time; it can be in one of the anal sacs or both of them.

Other Causes

Anal sac disorders arise from a variety of reasons including: 

  • The shape of their bodies; 
  • Allergic reactions (food and environmental); 
  • Bouts of diarrhea;
  • Constipation;
  • Excess amount of glandular secretions;
  • Poor muscle tone of the anus; and
  • Tumors, etc.

Causes for the frequency of anal sac disorders also exist and these include

  • Chronic skin infection containing bacteria or yeast with bacteria; 
  • Demodex or Sarcoptes – skin mite infestation; 
  • Obesity; and
  • Hypothyroidism.

It is good to keep in mind that if, as part of the dog’s grooming process, anal sacs are squeezed to specifically express the fluid too frequently, then it can actually lead to future anal gland problems. 


Physical exam: Any infection or abscessation can be discovered through a physical examination of the rectal area. The anal sacs would appear enlarged and the secretion that is usually clear or pale yellow-brown will be a thicker, brown fluid due to impaction. 

Types of testing: Fecal, blood and urine tests as well as a chemical profile will be used for a thorough diagnosis.  

Microscopy: This may be required if it is found that the anal sacs are too enlarged and you need to know if your dog has a tumor that is causing the impaction of the anal sacs.

Ultrasonography: Further to the physical examination and microscopy, an ultrasound may be necessary to discover the other reasons for a lack of secretion from the anal sacs. 

Symptoms of anal sac disorder in dogs

Scooting: If you see that your dog is scooting or dragging its butt, it is indicative of a potential anal sac disorder.

Licking or biting the rectum: Usually, when you see your dog licking its rectum, you may be able to ignore it. But, when it seems to be excessive, it is time to get it checked out. 

Difficulty in pooping: Is your dog straining to poop? Is your dog showing some signs of pain or even sometimes vocalising the pain when trying to poop? Time to go to the vet.

Swelling: Can you feel around the rectum and see if there is a bump or swelling in that area? If you do, it is a clear sign of something blocking the natural release of the anal sac fluid and is in urgent need to get expressed.

Blood or pus in the stools: This is easy to notice and recognize as a sign of ill health in your dog. If you see either blood or pus appearing in their stools, you can be sure there is a disorder that needs examining.

You may even find blood or pus in the general area where your dog sits or sleeps as in the bed or floor or carpet. 


Once you have shared a complete history with your dog’s vet and have heard the diagnosis, you will find that in certain cases a very simple way of reducing chances of impaction is possible. This includes changing the diet to include more fiber, the right amount of exercise, add Omega 3 fatty acids that help with any skin inflammation and impaction of the anal glands, avoid foods that cause allergies, and avoid frequent resorting to manual expressions of anal sacs.

Some dogs immediately respond to a change in diet with the increased amount of fibre; some do not. A changed diet may counter the effect of loose feces or constipation on  the anal sacs that lead to impaction. If there is found to be an infection, then a course of antibiotics might do the trick. Your dog’s vet would prescribe the right approach and medication.

In the case of impaction, an external expression of the fluid will be exercised. This is aided with a softening agent so that the process is easy and smooth. 

If the anal sacs show signs of infection, your dog’s vet would use antiseptic to clean and include medication. 

If the anal sacs show signs of abscession, they will be opened out near the anus so as to allow easy drainage of the fluid. Then, the sacs can be flushed and cleaned along with an infusion of antibiotics. Using a hot compress every 8 hours and holding it for around 15 minutes would help. Along with this, the vet would recommend regular flushing and a steroid inclusive antibiotic ointment as an external application. 

Worse case scenario is when there is chronic infection in the anal sacs. This would require surgery and a removal of the anal sacs. This is anal saculectomy and an expensive procedure. Your dog’s vet would also be able to advise you on the consequences of such surgeries. Some amount of nerve damage is likely, post anal saculectomy. This is definitely to be considered the last resort. 

If your dog’s vet finds that there are a few abnormal openings called fistulation in the anal sacs, some immunosuppressants may be prescribed.  

What can you do as a pet parent?

Observe and note down the symptoms as and when you see them. This will be useful when going to the vet. Once treatment begins, make sure you keep your scheduled appointments for follow-ups as and when your dog’s vet recommends. Don’t miss a single step of the treatment process. If you need a special collar – a recovery cone to keep your dog away from the anal area, include it as part of the treatment and get your dog used to it with patience and perseverance. 

Above all, ensure that you pay attention to changes in your dog’s behaviour and take steps to keep your dog healthy and happy!

The information contained in VOSD Vet Advice™ is not intended nor implied to be a substitute for professional medical action which is provided by your vet. You assume full responsibility for how you choose to use this information. For any emergency situation related to a dog’s health, please visit the nearest veterinary clinic.

Do you find this information useful? For more medical advice, visit the VOSD website.