Abscess is one of the most common prostatic diseases in dogs. Because of the blood-prostate barrier, only a few lipid-soluble antibiotics are effective when given systemically, and treatment must be continued for 3 to 6 weeks. Surgical treatment carries risks; thus, a good nonsurgical treatment has been sought. Tea tree oil is an essential oil with antiinflammatory and antifungal activity, as well as potent antimicrobial activity against a broad spectrum of gram-positive and gram-negative bacteria, including Escherichia coli and Staphylococcus aureus. In this study, the therapeutic effect of tea tree oil was assessed as a treatment for canine prostatic abscesses. The purulent material from the prostatic abscesses of 6 dogs was removed via ultrasound-guided transabdominal needle aspiration. Tea tree oil, equal to the volume of purulent material removed, was then injected into the cavities of the abscesses. Cultures of the purulent material revealed E coli or S aureus in 5 dogs and Enterococcus species in the sixth dog. Ultrasonographic evaluation of the dogs 3 weeks later revealed markedly reduced prostatic abscess cavities in 2 dogs and slightly contracted cavities in 4 dogs. Removal of purulent material followed by injection of tea tree oil into the prostatic abscesses of these 4 dogs was repeated. No purulent material was found 3 weeks after the second treatment. Pyrexia and anorexia seen at the beginning of the study had improved in all 6 dogs 3 weeks after the first treatment, and all clinical signs (including dysuria, dyschezia, and abdominal pain) had resolved within 3 to 6 weeks after the first treatment. The prostatic abscesses had not recurred in any of the dogs after more than 1 year.

COMMENTARY: Prostatic infections occur in 40% of dogs with prostatic disease, and the presence of abscessation with prostatitis varies, occurring in 60% of these patients in 1 study. While this study presents an intriguing possibility for managing canine prostatic abscesses, care must be taken in a procedure such as this one to avoid creating sepsis along the aspiration needle track. However, if treatment with systemic antibiotics and induction of prostatic involution (eg, castration) do not resolve the abscess, tea tree oil could be an interesting alternative to surgery. Further studies using more patients would be necessary to investigate this as a possible option.

Treatment of prostatic abscesses by aspiration of purulent matter and injection with tea tree oil into the cavities of dogs. Kawakami E, Washizu M, Hirano T, et al. J VET MED SCI 68:1215-1217, 2006.