How do you treat abscesses in dogs?

Our dogs can get up to all sorts of mischief. Occasionally, this can result in an infection, which may lead to an abscess. How an abscess affects your dog depends on the size and location of the abscess. These factors also influence how your vet will want to treat it.

What is an Abscess?

Abscesses are most commonly caused by bacteria, although they can arise from other types of infection. When bacteria break through the body’s physical defences, such as through a cut in the skin, the immune system reacts by activating infection-fighting white blood cells. These activated cells are then sent to the site of infection. Inflammation is also triggered by the invasion. As the white blood cells fight off the infection, an accumulation of dead cells, dead tissue, and fluid can occur. This is pus. As the body tries to contain the infection, it creates a capsule around the pus, creating a pocket of infection, known as an abscess.

Types of Abscess

Abscesses can occur anywhere on, or in, your dog. The most common location for an abscess is externally, in the skin. Vets also regularly see dogs with abscesses associated with the anal sacs and occasionally dogs present with abscesses associated with the mouth and throat. These external abscesses are usually more obvious to an owner and more straightforward to treat.

The more dangerous form of abscess are internal. These can stem from any organ if an infection occurs there. Abscesses of the pancreas and prostate are examples of internal abscesses that vets periodically see in dogs. Internal abscesses are more dangerous because of their effect on organ function, or the risk of septic spread if they burst.

Abscess of the Skin

This type of abscess usually results from something penetrating into the skin from outside. You may notice a cut or wound that later swells into a bump. The skin may redden, and it may feel either firm, or soft and spongy. Local inflammation and infection can be uncomfortable, and you may notice your pet is reactive to the area being touched. Your dog might feel a bit under the weather at this time or could behave as normal.

In breeds with long or thick coats, a wound or swelling may not be immediately obvious. If the infection is not brought under control by the body’s immune response, or by medical intervention, then the abscess may burst. This occurs due to continued tissue death as well as a build-up of pressure from the swelling and pus. When an abscess bursts, animals are inclined to lick them, and this may be the first time you notice a problem. Hair may fall out, or the pus and saliva might make the fur wet and sticky. This is also the point in the infection where you are most likely to notice a bad smell.

Foreign objects that burrow into the skin, such as barley grass seeds or thorns, can trigger an abscess. These typically occur between the toes after your dog has stood on them. Short-legged dogs, curly-coated, or long-coated dogs may also get burrowing grass seeds in skin folds, including the armpits and groin. Dog- or cat-bites are another common cause of abscess due to the culprit’s tooth pushing mouth bacteria through the skin into deeper tissues.

Anal Sac Abscess

Dogs have a pair of sacs with glands that open through ducts either side of the anus. These glands produce a pheromone which dogs sniff when they greet each other. Whenever your dog poops, these sacs should squeeze their contents out, covering the deposited faeces. Sometimes, bacteria pass up the duct into the sac where they fester into an abscess. This may not be immediately obvious to an owner until it bursts through the skin to the outside.

Prior to bursting, you may notice your pet licking under their tail. A red mark starts to appear on the skin next to the anus before it bursts. Licking often continues after bursting because of the discharge. Depending on the size of the swelling around the sac, your dog may show discomfort with pooping.

Dental and Oral Abscess

Because dogs like to chew objects as well as grab and chase objects during play, abscesses under the tongue (sublingual) or the back of the throat (pharyngeal) occasionally occur. Sticks or splinters are a common culprit for this, and penetrating injuries are a known risk if you throw sticks for your dog. Chewing cooked bones is another risk factor due to sharp pieces breaking off in the mouth. Both sublingual and pharyngeal abscesses are usually quick to develop a foul smell, but your dog will usually look uncomfortable generally, or specifically while eating. They may also drool saliva out the mouth or have difficulty opening or closing their mouth.

Broken teeth (often from chewing hard objects and raw bones) and gum disease can result in a tooth root abscess. Bacteria reach the root if a broken crown exposes the inner pulp cavity, or if the gum and socket support around the tooth root recedes (periodontitis). Infection builds into an abscess which can swell and burst through the gum, the nasal passage, or the outer surface of the face. Upper molar roots sit just below the eye, so abscesses there usually cause a firm swelling below the eye that eventually bursts through the skin. There may be bad breath or discomfort with eating, but many dogs mask dental pain and continue to eat.

Internal Abscess

Internal abscesses can occur from inhaling or ingesting something foreign or irritating. Inhaling food (aspiration) or objects such as grass seeds, can trigger an abscess in the lung tissue. Because breathing becomes compromised, you may notice your dog’s breathing is laboured, or they may develop a cough.

Swallowing sharp objects, such as sticks or kebab skewers, can result in the offending object poking through the gut wall, or completely exiting into the body cavity. An abscess can form around the foreign object itself, or around the hole if there is leakage of gut fluids. This process is very painful, and your dog will likely stop eating, could vomit, and may develop a firm tummy which is painful when touched.

Pancreatic abscesses can occur as a complication of pancreatitis.

Pancreatitis results from the pancreatic enzymes, which usually activate in the gut to digest the fat in the diet, becoming activated within the pancreas resulting in digestion of pancreatic tissue. Pancreatitis is itself painful and often triggers vomiting, but a pancreatic abscess is a much more severe form of the disease.

Male dogs occasionally get infection of the prostate, known as prostatitis

It is much more common in entire male dogs and usually results from a urinary tract infection. If inflammation causes a blockage at the exit duct, the infection within the prostate develops into an abscess. As with other internal abscesses, this is a painful condition, and affected dogs may have pain and difficulty with urination, or they may have an increase in urination frequency. Blood may be seen in the urine.

Dogs with internal abscesses will usually have generalised signs of ill-health as well as symptoms specific to the affected organ. They may have a fever, which can cause lethargy making your pet appear withdrawn or sleepy. Pain can also make your pet reluctant to move, and some individuals can become vocal, defensive or snappy if you touch them.

Medical Care of Abscesses

If you suspect your dog is unwell, or you notice a wound, swelling, or bump on your dog’s body, it is important to seek veterinary attention to determine the cause. Your vet can then advise the best treatment plan for your pet. This most often involves medical management at home but may also include surgical management or hospitalisation.

One of the smallest forms of skin abscess is a pimple (known as a pustule). A single pustule or small patch of pustules that is not itchy or uncomfortable, may need no medication at all as these can often self-resolve. Young, growing dogs sometimes get large patches of pustules on their underbelly, known as juvenile acne. Allergy-prone dogs can also break out in a lot of pustules. Larger patches can be more uncomfortable and may warrant a medicated skin wash or oral antibiotics.

Most other forms of external abscess and all bacterial forms of internal abscess will require antibiotics. The specific antibiotic used will depend on the location and cause of the abscess. It is usually chosen based on the most likely bacteria to be involved, for example, a bite wound will likely be infected with oral bacteria, and an anal sac infection will likely involve bacteria that came from the digestive tract.

With severe or recurrent abscesses, your vet may recommend taking a swab from the abscess to send to a laboratory for culture

This allows identification of the exact bacteria involved. Antibiotic sensitivity testing can also be used to determine the best antibiotic, or combination of antibiotics, to use against the infection. Regardless of the choice of antibiotic, it is important to give the entire course according to the prescribed instructions.

Most antibiotics will be given orally, with the majority of options being a tablet. A few liquid or capsule options exist also. If you think your dog may be difficult to orally medicate, it is important to discuss this with your vet, as missed doses could reduce the effectiveness of treatment. Some options may need avoiding if your dog has a known allergy or a food sensitivity to the flavour additive in some brands. If your dog is very sick or requires internal surgery, they will likely receive intravenous antibiotics at the start of their treatment.

Additionally, your vet may dispense pain medication to help with the inflammation and discomfort of the abscess. These will also usually be given orally, and there are tablet and liquid options available. If your dog has a reduced appetite or a fever, they may instead be given injections to commence treatment.

For external abscesses, a Buster collar may be needed

Also known as an Elizabethan Collar, or ‘Cone of Shame, this is used to prevent licking. Licking not only risks causing further damage to the already fragile skin, but it can also add to the bacterial load in the area. If there is an active discharge from a burst abscess, your vet may provide you with a skin disinfectant to help clean and dry the area.

Surgical Intervention

If an abscess is suspected to have occurred due to foreign material, then surgery will need to be performed. This involves removing the offending object, as well as cleaning out (debriding) the diseased and damaged tissue before suturing the wound closed to allow healing. Large abscesses or deep bites may also benefit from being debrided to help reduce the quantity of infected tissue. In some cases, the whole abscess may need to be cut out. Depending on size, this could require a drain to be placed, or a skin graft to be used to provide adequate wound closure and healing.

If your dog suffers from recurrent anal sac infections, your vet may discuss flushing the sac through the duct or removing the anal sacs in their entirety to prevent future problems. Removal is best done when the infection and inflammation are under control but does carry some risks which your vet will discuss with you.

Although antibiotics and pain medication will relieve the symptoms of a tooth root abscess, they will not cure the infection. As in people, a root canal may allow the tooth to be saved for function after draining the infection but is not always suitable or available locally. More commonly, dental abscesses require the diseased tooth or teeth to be extracted. This requires dental x-rays to confirm the number of affected teeth. Removal of the entire tooth structure may involve removing some of the bony socket to facilitate the extraction.

When medical management is not sufficient alone, internal abscesses often require surgery to treat them

As affected dogs may be quite sick, your vet may recommend hospitalisation for initial stabilisation before performing a general anaesthetic. An ultrasound, CT scan or MRI may be required to plan the best surgical approach. Removal of the whole abscess would be the optimal goal but is not always possible, especially if doing so compromises the structure or function of an organ.

Within the abdomen is omentum, a part of the lining of the cavity which may be folded over to create a pouch round the organs. It has a rich blood supply and is packed with both immune cells and stem cells. This can sometimes be used to pack inside an abscess’ capsule to promote healing, a treatment known as omentalisation. In the case of a prostatic abscess, omentalisation may be combined with castration due to the prostate’s response to testosterone – remove the testosterone and the gland shrinks away almost to nothing, helping to resolve the infection.

Conclusion

Abscesses arise from infection and the subsequent immune response. They are most often bacterial in origin and can occur externally or internally. The size and severity influence the degree of symptoms, as well as the level of intervention required to manage them. Your veterinary team can advise on the best course of action to treat your dog’s condition, whether this is at home as an outpatient, or in the clinic if more supportive care is required.