Final answer:
For chronic canine keratoconjunctivitis sicca, the preferred treatment is topical cyclosporine and topical steroids to stimulate tear production and manage inflammation, tailored to the individual needs of the dog.
Step-by-step explanation:
The treatment of choice for chronic canine keratoconjunctivitis sicca (KCS), also known as dry eye syndrome, is topical cyclosporine along with a topical steroid. The condition is characterized by a deficiency in tear production, leading to dryness, inflammation, and discharge.
Cyclosporine acts to stimulate tear production and decrease inflammation in the eye, whereas steroids can help reduce the immediate inflammatory response. Although corticosteroids have a role in the management of certain inflammatory eye conditions, their use is controversial with infections like Acanthamoeba keratitis due to their immune-suppressing effects and potential to worsen the infection. A Schirmer tear test is often used to diagnose KCS by measuring tear production, and a result indicating no tear production confirms the need for treatments that stimulate tear secretion and manage inflammation.
Other treatments mentioned, such as systemic administration of immunosuppressants or antibiotics, are typically reserved for specific types of conjunctival or corneal infections, such as those caused by bacteria like Chlamydia trachomatis or Neisseria gonorrhoeae, and are not the primary treatment for KCS.
Antibiotics are ineffective against viral causes of conjunctivitis and are only used when a bacterial infection is present. In comparison, Herpes keratitis requires antiviral medications, as it is caused by the Herpes Simplex Virus-1 (HSV-1), and bacteria-induced conjunctivitis may require antibacterial agents.