Q: My 5-year-old male cat has been suffering from a stuffy nose that has recently gotten much worse. I’ve seen three different veterinarians, and we’ve tried amoxicillin, prednisone, and clindamycin.
They helped a little, but as soon as the course is over, the problem returns (actually, one worked for four months). He has had several sinus flush-outs and been scoped (no polyps). Can you give me any advice on how to proceed?
A: Thanks for getting in touch, and I am sorry to hear of your kitty’s problems. Rhinitis (inflammation of the nasal passages) is fairly common in cats, and, as you are experiencing, figuring out its cause and treating it can be challenging. Perhaps a review of the most common causes of feline rhinitis would be helpful.
The most common primary cause of chronic rhinitis (i.e., lasting four weeks or longer) in cats is infection by viruses that target the upper respiratory tract, including feline herpesvirus (FHV) and feline calicivirus (FCV). These viruses are highly contagious, and most cats are exposed to them at some point, with most recovering from infection after experiencing a brief period (i.e., a few weeks) of upper airway symptoms (i.e., nasal discharge, sneezing).
In rare cases, calicivirus infections can cause much more serious and potentially life-threatening illness, but this is likely not germane to the situation that your cat is currently experiencing.
The relatively quick recovery that is commonly seen with these infections is particularly prevalent in cats that are appropriately vaccinated.
Vaccination against these viruses does not necessarily prevent infection, but vaccinated cats are less likely to become infected, and if a cat does become infected after vaccination, the degree of illness that infection will cause is usually significantly decreased.
Importantly, cats that are infected with FHV, which is considered the most common cause of chronic rhinitis in cats, are infected for life, and they may intermittently experience bouts of illness/symptoms, particularly during times of stress.
Although bacterial infections are often found in cases of chronic feline rhinitis, these most commonly occur secondary to damage to the lining of the nasal passages caused by an initial viral infection. More recently, allergens have been proposed as playing a more significant role in chronic feline rhinitis than previously thought, particularly in cats that show signs of other allergic airway conditions like feline asthma.
Other less common causes of chronic rhinitis in cats include fungal infection, nasal polyps (which have been ruled out in your cat’s case), foreign bodies, dental disease invading the nasal sinuses, narrowing of the nasopharyngeal (i.e., back of the oral/nasal cavity) region, cleft palate, and certain types of cancer.
A presumptive diagnosis of virally-induced chronic rhinitis in cats (called idiopathic rhinitis) involves ruling out these other causes of rhinitis in cats.
This usually requires bacterial/fungal culture of samples obtained from the nasal cavity, rhinoscopy (visualization of the nasal cavity with a small flexible camera), imaging studies including radiography (X-rays) and/or CT, and, in some cases, polymerase chain reaction (PCR) of nasal flush samples for pathogens (usually viral). In some cases, nasal biopsies may be recommended.
Treatment of idiopathic rhinitis can be challenging, and affected cats are at risk of repeated bouts of symptoms throughout their lives. In most cases, therapy involves a combination of intermittent antibiotic therapy to control secondary bacterial infections, nebulization to make nasal secretions less thick and facilitate breathing, decongestants, and anti-inflammatory drugs. In rare cases, surgery may be recommended if structural abnormalities are believed to contribute to symptoms.
Owners should understand that therapy is geared toward controlling symptoms and preventing complications, and that there is no true “cure” for this condition.
Please discuss these points with your veterinary team, and continue to work closely with them to assure best care for your boy.
Best of luck, and please send an update when you can.