If a dog has an abscess often the owner will notice a painful swelling or mass which seems to appear quite rapidly. Sometimes there is a foul smelling discharge present which is often yellowish or blood tinged. This matter is commonly called pus and consists of dying cells and tissue together with serum. The dog may show signs of being in pain and will often stop eating and become lethargic, it may also have a high temperature, but measuring this should be left to the vet! If it is possible to gently palpate the mass it may feel either fluid like or very hard but if attempting to feel the mass remember that even the most placid friendly pet may react aggressively to pain. Common positions for abscesses in dogs are the anal glands, and oral cavity although other parts of the body may be affected, such as the prostate, mammary glands and eyes (orbital abscess); much less common sites are the brain, liver or the lungs. Percutaneous (i.e. skin) abscesses are much less common in dogs than in cats.
Common organisms found in abscesses include Staphylococcus, Streptococcus, Pseudomonas, E.coli and many others. Foreign bodies are also sometimes found within an abscess, this is often material which the dog has been chewing in the case of oral abscesses (e.g. splinters of wood).
When presented with a dog with the signs indicating an abscess the vet may feel it necessary to perform some tests. These tests may include taking an aspirate; this involves carefully inserting a fine needle into the mass to try and withdraw some pus (fine needle aspirates can be used to withdraw cells from masses in order to determine a diagnosis in other sorts of masses as well). The vet may also feel it is necessary to take X-rays to find out if there is a foreign body inside the lesion or in the case of facial abscesses to check the condition of the dog's teeth. Blood samples can also provide useful information. Other tests may be suggested by your vet. Do not be unduly concerned however, if the vet feels no diagnostic tests are initially required as these commonly seen masses are often diagnosed on presenting signs alone.
Treatment usually consists of ensuring adequate drainage for the pus inside the abscess and concurrent treatment with antibiotics. If the abscess has not already burst the vet will drain it by making an incision into the mass in such a position which allows the pus to drain. This may often be done under anaesthesia and sometimes the vet may insert a surgical drain to ensure successful drainage. If a drain is inserted it will look like a tube which usually appears at both ends of the wound and will have been sutured into position. If there is no drain, the wound will be left open and this can appear slightly alarming to the owner but is necessary to allow drainage of pus. In some cases owners may find the appearance so alarming that they wonder why the vet does not suture the wound, I have even had cases where the owners try to insist that I do so. This is completely the wrong thing to do as it would prevent drainage of pus and would usually result in further wound breakdown and discomfort for the animal. If the abscess is caused by a dental problem then dental treatment will be required. This usually involves the removal of the infected tooth or teeth. Again the prognosis is usually good following appropriate treatment.
Antibiotic treatment will be given and may be all that is necessary if the abscess is already burst and draining freely when the vet sees it. The choice of antibiotic given will depend on the type of infection believed to be causing the problem and also upon the individual animal being treated. Often a general broad spectrum antibiotic is prescribed, but your vet may wish to culture a sample of pus taken from the abscess in order to find out which drugs the organism responsible is most sensitive to. Commonly used antibiotics include amoxicillin/ clavulanic acid, and trimethoprim/sulphadiazine among others.
Usually the outcome for abscesses is good with the majority of dogs responding well to treatment within a week to ten days. However the prognosis may be poor if an abscess affects the brain, liver or lungs and also if an abscess ruptures internally. Prevention of recurrence is dependent upon the cause of the abscess, but measures could include prevention of chewing material likely to cause abscesses in the oral cavity, good dental hygiene and regular check ups, prevention of impaction of the anal glands, and possibly castration in the case of prostatic abscess.
If you believe your dog may have an abscess please consult your veterinary surgeon.