Anal gland problems in dogs: blockage, infection and abscesses

Overview

Dogs have 2 small anal sacs beneath the skin, one on each side of the anus. Each sac's lining produces secretions that drain through a small duct beside the anus. A strong smell is a normal property of these secretions. Their likely function is scent marking.

Common anal gland problems include impaction, sac inflammation and abscesses. These are distinguished from anal sac tumours, a different disease group. In British veterinary records, non-tumour anal sac problems were diagnosed in about 4.4% of dogs during one year. These were records from 2013. The figure does not describe inflammation alone or provide a universal risk estimate for dogs.

An anal sac normally ranges roughly from pea-sized to grape-sized. Even healthy secretions can be yellow, brown or grey. Consistency can range from liquid to a putty-like mass.

Causes

Passing faeces normally compresses the sacs so secretions leave them. A gland may also empty suddenly when a dog is frightened or excited. If emptying is incomplete, secretions can thicken and the gland enlarge. With impaction, material sometimes becomes so paste-like that it cannot drain normally through the duct.

Secretions remaining in the gland for a long time can favour bacterial multiplication and inflammation. If an inflamed gland's duct becomes blocked, an abscess can result. However, inflammation can also occur without blockage. The problem is therefore not always simply an overfilled sac.

Narrow ducts can impair emptying even when secretions have a normal consistency. After diarrhoea, pressure from faeces may be insufficient to empty the glands. Generalised seborrhoea, involving greasy skin, can be associated with increased gland secretion. This can contribute to accumulation.

Thick paste may remain on the sac walls after expression. Signs can then return quickly. Flushing can sometimes settle the problem for longer than expression alone.

Risk factors

Impaction and inflammation are more common in small dogs than in large or giant breeds. However, any breed can have problems. They are generally seen in dogs older than 1 year. No clear overall difference in susceptibility between the sexes has been established.

In British records, the annual proportion was 14.83% in Cavalier King Charles Spaniels and 13.78% in King Charles Spaniels. Shih Tzus, Bichon Frises and Cocker Spaniels also had a higher diagnosis risk than crossbreeds. This comparison covered all non-tumour anal sac disorders, rather than abscessed inflammation alone.

Food-allergic dermatitis and atopic dermatitis may be associated with anal gland problems. Chronic diarrhoea, constipation and structural gland abnormalities can also predispose to signs. Poor muscle tone associated with excess weight may impair drainage. However, the British population comparison did not demonstrate an association between obesity and anal sac disorders.

In the British comparison, short-nosed dogs had about 2.62 times the risk of anal sac disease compared with long-nosed dogs. Spaniel-type dogs had 2.09 times the risk compared with non-spaniels. Low activity has also been associated with more frequent gland problems.

Impaction risk rises with age. In the British comparison, Dachshund-type dogs had about 1.38 times the risk of anal sac problems compared with other dogs. Poodle-type dogs had 1.46 times the risk compared with non-Poodle types.

Typical symptoms

Your dog may start dragging the bottom along the floor, grass or another surface. This is often called scooting. Common observations include:

• Repeated licking or biting around the anus.
• A strong fishy smell or discharge marks on the floor.
• Holding the tail low.
• Reluctance to pass faeces or prolonged straining.
• Pain when sitting or having the hindquarters handled.
• Redness, swelling or bloody discharge beside the anus.

Signs may initially be so mild that you notice only reluctance to pass faeces or slight constipation. Abscess pain can be very severe.

Your dog may also be restless. They may bite at the hip region. Impaction alone is not always obviously painful, although it causes discomfort. Secretions from an inflamed gland may contain blood.

Complications and consequences

Inflammation can progress to a pus-filled abscess. An abscess may burst through the skin, releasing pus and blood. The resulting draining tract leaves an oozing wound beside the anus. Rupture does not remove the need for treatment. The area may require opening and flushing under sedation or general anaesthesia.

Repeated rupture through the skin creates scar tissue that can impair gland function and complicate removal. Pain when passing faeces can cause constipation. The outlook for non-tumour anal sac disorders is usually good. However, some dogs have recurrences and need a longer-term care plan.

A sac can sometimes rupture towards the rectum instead of the skin. Scar tissue between the sac and rectum can impair healing and worsen the outlook.

Diagnosis at the vet

The vet inspects the anal area and feels the sacs with a finger through the rectum. A painful dog or one resisting handling may need sedation for an adequate examination. Impacted sacs feel like firm masses. Their contents can be a thick brown paste.

Secretions may be examined microscopically for bacteria, yeasts and inflammatory cells. Inflamed material may contain many white blood cells and bacteria. Bacterial culture can help choose medication for a recurring infection. Smell or colour alone does not identify every infection, as normal secretions vary considerably.

A firm, enlarged sac that will not empty even with flushing may raise suspicion of a tumour. Ultrasound helps distinguish a tumour from inflammation or an abscess. Biopsy confirms a suspected tumour. A tumour can sometimes cause increased drinking and urination because of raised blood calcium.

A draining tract from an abscess must be distinguished from perianal fistulosis. The latter is an immune-related disease rather than simply a blocked sac. A swelling around the anus may also involve a perineal hernia or another tumour.

An anal sac tumour may be painless, so lack of pain does not rule it out. Blood calcium may be measured when a tumour is suspected, as it can raise the level.

Treatment

The vet prescribes treatment and medicines. Simple impaction is often treated by gently expressing the sacs. Dry contents can be softened with a solution introduced into the sac. Sometimes repeating expression after 24–48 hours is useful. This need is assessed at the practice, rather than being a home routine for every dog.

Local treatment of inflammation involves emptying and flushing the sac. Doing this without an antibiotic is a first-line approach. An antimicrobial medicine may also be used when needed. Antibiotics are considered particularly when inflammation spreads into tissue around the sac. Local treatment is still necessary then.

Pain and inflammation can be treated with vet-prescribed medicines. Painful flushing may require sedation or general anaesthesia. Sometimes flushing is the only way to empty the sac. An abscess is opened and drained if it has not already ruptured. A collar prevents licking of the healing area.

Surgical removal of the anal sacs may be considered for persistent or frequently recurring disease. Inflammation and scarring can make the operation technically harder. Removal can improve quality of life in a severely affected dog.

Possible surgical complications include infection and faecal incontinence. Incontinence may result from nerve damage in the area. Incomplete removal or rupture of the sac can leave a chronic draining tract. Scarring within the anal sphincter can make passing faeces difficult.

In some cases, the vet places a product containing a topical antibiotic and corticosteroid inside the sac. Supportive abscess care may include a warm compress for 15–20 minutes as instructed by the vet. Local abscess care may also require clipping surrounding hair and cleaning the skin.

Prevention

Preventing recurrence involves treating any skin disease or intestinal problem. Added dietary fibre can increase stool bulk and help compress the glands empty during defecation. An overweight dog may benefit from weight loss. Diet is chosen individually, particularly if an underlying allergy is suspected.

For a dog with repeated impaction, the vet may plan regular checks and expression when needed. However, do not start squeezing a symptom-free dog's glands yourself as a precaution. Pressure can rupture an impacted or inflamed sac, causing bleeding and pain.

Important for dog owners

Record how often your dog licks the bottom or drags it along the ground. Also note stool consistency, difficulty passing faeces and any skin signs. Bring details of previous expression, flushing and medicines. During monitoring, distinguish a bad smell alone from pain and a visible wound. Even normal secretions vary in colour and consistency, so colour alone cannot identify the problem.

As first aid, the area can be rinsed with warm water, but a painful dog or one with ongoing signs needs examination. Do not try to squeeze a painful swelling or puncture an abscess yourself. Persistent licking or repeated rubbing is a reason to book an appointment. After treatment, monitor successful defecation, pain and discharge, and report worsening to the vet treating your dog.

Frequently asked questions

Is scooting always caused by anal glands?

Anal gland problems are a common cause of dragging the bottom. However, not every sign around the anus comes from these glands. Examination may need to distinguish another tumour or a perineal hernia, for example. The sacs can be felt with a finger through the rectum.

Does inflammation always need antibiotics?

Not automatically. One first-line approach is emptying the sac and repeated antiseptic flushing without antimicrobials. Medication needs depend on examination and factors such as spread into surrounding tissue. The vet treating your dog chooses suitable care based on the findings.

Can I empty the glands at home?

Do not start squeezing a painful or swollen gland yourself. Pressure can rupture an inflamed or impacted sac and cause more pain and bleeding. The vet can plan an individual checking and expression schedule for a dog with recurring impaction.

Does fibre help anal gland problems?

Fibre can increase stool bulk and help the glands empty during defecation. However, it does not replace drainage of a painful abscess or other local care. An abscess may need opening and flushing under sedation. Dietary changes are tailored to your dog's other health needs.

When is gland removal considered?

Surgery is considered when treatment does not settle the problem or it recurs frequently. It can improve quality of life in a severely affected dog. The decision also weighs risks of infection and faecal incontinence. Long-standing inflammation and scarring can make removal harder.