What is FHV-1-associated conjunctivitis in a cat?

Category: Feline

My three-year old cat was diagnosed with herpes simplex in her eyes when she was a kitten. At the time the veterinarian called it conjunctivitis. She recently developed a discharge from both eyes and has dark goop in her eyes every day, which we just clean out. Have you heard of this and what should the treatment be? Any help you can give will be most appreciated. Thank you.

A viral infection that causes "pink eye." Herpesvirus (feline herpesvirus-1; FHV-1) can cause conjunctivitis ("pink eye") in the cat. Usually cats recover within 14 days of being infected, often without treatment. However, most cats, once infected with FHV-1, will harbor the virus long-term and about half of these "carrier" cats can experience recurrences later in life. Recurrent viral conjunctivitis can sometimes progress to viral keratitis (an inflammatory disease of the cornea, or outer clear shell, of the eye) and keratoconjunctivitis sicca (KCS), or dry eye. Cats may subsequently develop corneal ulcerations as well. Some cats develop chronic FHV-1-associated conjunctivitis, in which signs of the disease never go away.

There are many other reasons that a cat can develop conjunctivitis and discharge from the eyes. These include allergy, bacterial infection (especially with Chlamydia psittaci and Mycoplasma felis), fungal infection, and other viral infections (especially feline calicivirus), among other causes. Because of this, you will need to have your veterinarian examine your cat. He or she may want to perform other tests depending on what is found on physical examination.

The discharge may be composed of serous fluid with or without pus. When the discharge dries it appears as crusting around the eyes. The eyes are typically blood shot and the affected cat may or may not experience pain.

Affected cats are often treated with topical antibiotic eye drops. This medication is administered to prevent or treat secondary bacterial infections, including those caused by C. psittaci and M. felis, which often accompany FHV-1 infection. Sometimes systemic antibiotics are needed. In severe cases, especially in those that are recurrent or when KCS or chronic conjunctivitis is present, affected cats may also be treated with topical antiviral agents. Cats with KCS may also be given cyclosporine, an immune system suppressor, to attenuate the inflammation associated with this viral infection. Anti-inflammatory agents may be given if pain is present. Lysine, an amino acid, may help to speed recovery. Eyewashes are used to clean the eyes of the discharge.

I recommend that you have your veterinarian examine your cat so that appropriate treatment can be given. It is possible that this problem is not related to the herpes infection that your cat had earlier in life and should therefore be evaluated.