Rhinitis and sinusitis are the inflammation of the mucous membrane (lining) of the nose and sinus. They may be acute (sudden onset/short duration) or chronic (slower onset/longer duration), noninfectious or infectious, and are not an uncommon occurrence in veterinary medicine. Regardless of the underlying cause, secondary bacterial invasion/infection is relatively common.

It is important to establish the underlying cause, as treatment modalities are multiple and varied. The clinical signs and progression of disease associated with rhinitis and sinusitis may be mild and slow, however, depending on the individual case, signs may be severe and rather devastating. The appropriate diagnostics and therapeutics would be recommended and tailored to that individual.

There are several diseases/disorders that can appear similar to and/or cause rhinitis and sinusitis. These include:

Infectious Diseases

Viral. These include adenovirus, distemper, parainfluenza virus.

Fungal. These include ryptococcus, aspergillus, blastomycosis, histoplasmosis and rhinosporidiosis.

Bacterial. These include primary disease (Bordatella, Pasturella) or secondary invader.

Parasitic. These include cuterebriasis, capillaria and pneumonyssoides

Noninfectious

Facial trauma

Foreign body - plant material, stones, teeth

Allergic/irritant - pollen, mold, litter, cigarette smoke

Immune mediated (lymphocytic plasmacytic)

Dental disease

Oronasal fistula (communication between the nasal cavity and mouth)

Nasal/nasopharyngeal polyp (benign fleshy growth)

Cancer - lymphoma and adenocarcinoma most common

Severe clotting (bleeding) disorders often present with epistaxis (nasal bleeding), and need to be differentiated from rhinitis and sinusitis. These include:

Thrombocytopenia (a decrease in the number of platelets) can cause epistaxis. Platelets are essential for normal clotting, and a decrease in their number is often associated with spontaneous bleeding.

Warfarin toxicity (the ingestion of rat poison) can cause epistaxis by interfering with the normal clotting mechanism.

Liver disease (to include infections, inflammation, cancer) can interfere with the normal clotting mechanism, as a normal functioning liver is necessary to produce ample clotting factors.

Disseminated Intravascular Coagulation (DIC) can be associated with epistaxis. This is an overwhelming syndrome in which spontaneous bleeding is common.

Hypertension (high blood pressure) may cause epistaxis.