Sneezing & Nasal Discharge in Dog & Cat: Complete Guide

Sneezing is an involuntary, protective reflex that expels air from the lungs through the nose and mouth in a sudden, explosive manner to clear the upper airways. It is triggered when chemical or physical irritants stimulate the subepithelial receptors in the nose. Sneezing or nasal discharge may occur in diseases of the nose, sinuses and nasopharynx or may be secondary to lower airway or systemic disease.

What are the causes of sneezing & nasal discharge?

(A) Nasal & paranasal causes of sneezing & nasal discharge

Congenital	Cleft palate Ciliary dyskinesia Nasopharyngeal stenosis Choanal atresia
Inflammatory	Idiopathic lymphocytic-plasmocytic rhinitis Allergic rhinitis Nasopharyngeal stenosis Nasopharyngeal polyp (C) Polypoid rhinitis Foreign body
Infectious	Feline calicivirus Feline herpesvirus-1 Mycoplasma spp. Bordetella bronchiseptica Pasteurella multocida Aspergillus Penicillium Rhinosporidium Cryptococcus Pneumonyssoides caninum Eucoleus (Capillaria) boehmi Cuterebra sp. Linguatula sp.
Neoplastic	Neoplastic Adenocarcinoma Squamous cell carcinoma Chondrosarcoma Osteosarcoma Fibrosarcoma Lymphoma Transmissible venereal tumour Neuroendocrine carcinoma
Trauma	Blunt or sharp force
Dental disease	Tooth root abscess Oronasal fistula Vascular Malformation

(B) Nasal & paranasal causes of sneezing & nasal discharge

Haemostatic Disorder	Thrombocytopenia Thrombocytopathia von Willebrand disease Coagulation factor deficiency Congenital (hemophilia A and B, others) Acquired (anticoagulant rodenticide intoxication, disseminated intravascular coagulation, liver failure)
Vasculitis	Toxic Inflammatory Immune-mediated Systemic lupus erythematosus Neoplastic Infectious Ehrlichiosis Feline infectious peritonitis Rocky Mountain spotted fever Leishmaniasis
Hyperviscocity	Multiple myeloma IgM (Waldenstrom’s) macroglobulinemia Chronic lymphocytic leukaemia Lymphoma Ehrlichia canis Feline infectious peritonitis (rare) Amyloidosis Plasma cell leukaemia
Hypertension	Primary or essential (rare) Secondary Acute or chronic kidney disease Pheochromocytoma Hyperadrenocorticism Hyperthyroidism Hypothyroidism Acromegaly Polycythaemia Diabetes mellitus Overhydration
Infections	Infectious tracheobronchitis Distemper Bacterial bronchopneumonia

What are the clinical signs of sneezing and nasal discharge?

Most patients with nasal disease will present for evaluation of nasal discharge or sneezing. Signs of caudal nasal cavity disease include stertor, reverse sneezing, excessive swallowing, gagging, coughing, dysphagia, and changes in phonation. Clinical signs are not usually pathognomonic for a particular disease and various ancillary tests are required to reach a diagnosis.

(i) Stertor

This term refers to a snorting/snoring respiratory sound indicating an obstruction to airflow at the nasopharynx that usually resolves with open-mouth breathing. Nasal discharge, mass lesions, and nasopharyngeal swelling can cause it and it is classically heard in brachycephalic breeds due to an elongated soft palate, excessive nasopharyngeal tissue, and airway stenosis.

(ii) Reverse Sneezing

Reverse sneezing is a loud, sometimes violent, inspiratory snoring sound that occurs without warning. Lasting seconds to minutes, it may give clients the impression that respiratory distress is occurring. Irritation of the nasopharyngeal mucosa triggers spasms of the pharyngeal muscles, leading to obstruction of air passage to the larynx and transfer of secretions and foreign material to the oropharynx for swallowing. It is common, and usually of no consequence. Nasopharyngeal disorders such as a foreign body, the nasal mite (Pneumonyssoides caninum), viral infection, allergic rhinitis or epiglottic entrapment of the soft palate should be investigated when reverse sneezing is new or increases in occurrence.

(iii) Nasal Discharge

Location and character of nasal discharge may help formulate a list of differential diagnoses, keeping in mind the tremendous overlap amongst diseases that cause it. Discharge is typically unilateral with foreign bodies, oronasal fistulas, aspergillosis, and neoplasia, and bilateral in inflammatory, infectious, or allergic disease. It is classified as: serous, mucoid, mucopurulent, purulent, sanguineous (containing blood), epistaxis (frank haemorrhage), or food-containing. Nasal discharge may not be noted in nasopharyngeal disease, as secretions tend to be swallowed.

Serous discharge is watery, clear, and can be a normal finding. If excessive, it may be a sign of non-infectious inflammatory disease or a viral upper respiratory tract infection in cats.

Mucopurulent discharge is more viscous and opaque, usually having a white, yellow, or green coloration. Any nasal disease that causes inflammation and secondary bacterial infection can present with this type of discharge, thus making it nonspecific.

A sanguineous discharge occurs from damaged nasal mucosa and may be brought on by continuous sneezing alone. Significant nasal turbinate destruction or erosion of nasal vascular structures caused by craniofacial trauma, mycotic infection, or neoplasia, can cause a sanguineous nasal discharge or epistaxis. It can also be caused by systemic diseases (hypertension) or haemostatic disorders (thrombocytopenia, thrombocytopathies, vasculitis, or a coagulopathy).

Food material in the nasal cavity suggests a congenital abnormality such as a cleft palate, a dysphagic condition in a young animal, or an oronasal fistula in an older animal.

How sneezing and nasal discharge is diagnosed?

(a) Signalment of sneezing & nasal discharge

Young animals are more likely to have congenital or infectious causes of nasal discharge. Conversely, neoplasia and dental disease are more frequent occurrences in older animals. Animals housed together or stressed (shows, shelters, kennels, new home), or those exposed to regional outdoor environments (mycotic infection), are more susceptible to infectious diseases.

Brachycephalic dogs commonly have conformational causes of upper airway disease and less frequently nasal neoplasia, while brachycephalic cats are at increased risk of fungal rhinitis. Dolichocephalic breeds are overrepresented with respect to nasal disease, likely related to the greater surface area of their mucous membranes increasing exposure to inhaled irritants and allergens. They also have a higher incidence of fungal rhinitis and nasal tumours.

In cats, nonspecific inflammatory rhinosinusitis is likely the sequela of upper respiratory viruses. They alter normal nasal anatomy and defence mechanisms, causing a predisposition to secondary bacterial infections and an abnormal immune response. Cats with neoplasia are more likely to be older, have dyspnoea, or haemorrhagic or unilateral nasal discharge.

(b) History

A thorough history may assist in prioritizing diagnostic tests and treatments. The pet owner should be questioned about attendance at shows/kennels, trauma, travel, outdoor activities (exposure to foxtails/grass awns, fungal organisms) and recent anaesthetic procedures (nasopharyngeal gastric reflux, dental extractions).

Another diagnostic aid is the onset of clinical signs (per acute, acute, chronic). Paroxysmal sneezing in a dog that was recently outdoors might indicate a plant-origin nasal foreign body, especially if accompanied by pawing at the face. In contrast, acute sneezing in cats is commonly from a viral aetiology. It is less likely from foreign body inhalation due to the smaller opening of the external nares in cats. Nasopharyngeal foreign bodies may occur secondary to vomiting or regurgitation of grass or fur into the nasopharynx. Clients may report reverse sneezing, increased swallowing or gagging (postnasal drip), coughing, or audible breathing noises (stertor) in pets with caudal nasal cavity disease.

(c) Physical Examination

Clinical suspicion of nasal disease can be confirmed by a thorough physical exam, although at times no abnormalities may be noted even though significant disease exists. The nose is examined for the presence of discharge, ulceration/crusting around the nares, depigmentation of the nares (nasal aspergillosis), asymmetry of the nose and/or face (nasal neoplasia, cryptococcosis), and pain over the dorsum of the nose (nasal aspergillosis/neoplasia). Placing a glass slide, a few hairs or a wisp of cotton in front of each nares and noting condensation or movement, respectively, assesses patency of the nasal passages. In a quiet area, listen for nasal stertor while keeping the patient’s mouth closed.

A thorough oral exam, usually necessitating anaesthesia, is performed as part of a complete evaluation. Mucosal ulceration (feline calicivirus), fractured teeth, oronasal fistula, cleft palate, inability to depress the soft palate or a ventral displacement (nasopharyngeal space-occupying lesion) may be noted. Halitosis may indicate dental disease, oronasal fistula, or a foreign body.

Exophthalmos, prolapse of the nictitans, deformity of the facial bones, or inability to retro-pulse the eye should lead to suspicion for a retrobulbar mass. Epiphora may be a sign of nasolacrimal duct occlusion. Fundic examination may reveal chorioretinitis (neoplastic or infectious diseases) or tortuous retinal vessels, retinal haemorrhages, or retinal detachment (systemic hypertension).

Nasal disease extending beyond the cribriform plate (neoplasia/aspergillosis) may affect the central nervous system and therefore a neurological exam should be performed.

Primary thoracic diseases may cause secondary nasal signs from secretions coughed into the nasopharynx. Crusting of the nares with the absence of sneezing or nasal discharge suggests keratoconjunctivitis sicca (KCS) or primary dermatoses such as discoid lupus erythematosus.

Epistaxis is the most common clinical sign associated with thrombocytopenia. If petechiae, ecchymoses, or melena are noted, a haemostatic disorder should be the primary consideration.

Diagnostic Plan for Sneezing & Nasal Discharge

Using the information gained from the clinical signs, signalment, history, and physical examination, an appropriate systematic diagnostic plan can be formulated. Despite thorough evaluation, 36.3% of cases of nasal disease in dogs remain undiagnosed and 23.7% of dogs and 64% of cats are diagnosed with nonspecific rhinitis. Likely contributing to these numbers are cases of early neoplasia or foreign bodies, where repeated testing would probably lead to a diagnosis. Testing should also be repeated in patients with chronic rhinosinusitis that have worsening of clinical signs, to investigate the development of a second disease process.

In most cases of nasal disease, complete blood count and chemistry panels are not usually helpful in determining a diagnosis. Despite this, they must be performed to screen for systemic diseases manifesting with nasal signs and before undergoing diagnostics that require general anaesthesia. Cryptococcal serology should be performed in cats. Aspergillus serology by agar gel immunodiffusion test may support a diagnosis of fungal rhinitis, as it was shown to be highly specific (98%) but not sensitive (i.e., a negative result does not rule out the disease). Fungal culture as a sole means of diagnosing fungal rhinitis is not recommended due to the possibility of nonclinical transient fungal organisms. Testing for respiratory viruses (feline calicivirus, feline herpesvirus-1) by immunodiffusion, enzyme-linked immunosorbent assay, or polymerase chain reaction is of no use in most situations due to the high prevalence in healthy cats. In cases of epistaxis, a platelet count, coagulation times (prothrombin time, activated partial thromboplastin time) or levels of proteins induced by the antagonism or absence of vitamin K, and blood pressure should be assessed, and, if indicated, a buccal mucosal bleeding time (BMBT) should be performed.

Cytology of nasal secretions usually reveals nonspecific inflammation. Occasionally, fungal organisms (Cryptococcus sp.), parasitic ova (Eucoleus boehmi) or neoplastic cells are noted. Samples obtained by swabbing, brushing, flushing, or impression smears of tissue fragments can be used. Facial or nasal swellings and enlarged lymph nodes should be sampled by fine needle aspiration or biopsy (needle core [Tru-Cut] or punch).

Bacterial culture of nasal discharge or the nasal cavity (deep swabbing or biopsy) is generally considered of little value as it commonly yields a mixed growth of normal commensal microflora. Although primary bacterial rhinitis is rare, notable exceptions include Pasteurella multocida (dogs), Bordetella bronchiseptica (dogs and cats) and Mycoplasma spp. (cats).

Further assessment beyond these initial steps requires general anaesthesia and should begin with an oral examination. If dental disease is suspected, dental radiographs should be acquired. Imaging studies should be obtained before performing dental probing or endoscopic procedures to avoid causing haemorrhage within the nose that will affect visualization. Regardless of the diagnostic method chosen, it cannot be stressed enough that bilateral examination and sampling of the nose should always occur even when unilateral disease is suspected.

(a) Skull Radiographs

Although not the ideal imaging modality when investigating nasal disease, routine radiography may reveal the extent and character of the disease and help direct biopsy sampling. Advantages are that it is widely available and relatively inexpensive. Disadvantages include the need for general anaesthesia for proper patient positioning and the inability to detect subtle changes within the nasal cavity. Superimposition of structures or accumulated fluid may obscure abnormalities and can be minimized by obtaining intraoral dorsoventral and/or open-mouth ventrodorsal views, the latter allowing assessment of the cribriform plate. Lateral oblique views and rostro-caudal views allow visualization of the dental arcade and frontal sinuses, respectively.

Rhinitis in dogs and cats, regardless of cause, can have a variable radiographic appearance depending on the chronicity and severity. Destruction of conchae can be a feature of both rhinitis (fungal/other) and neoplasia. This finding along with soft tissue swelling, bony invasion and ipsilateral sinus opacity are more commonly noted in nasal neoplasia. In cats, Cryptococcus neoformans does not usually cause bony destruction. Radiopaque foreign bodies may be identified. Radiolucent foreign bodies can be localized by the appearance of a soft tissue opacity caused by secondary inflammation and discharge.

(b) Computed Tomography (CT)

In contrast to skull radiographs, CT is much quicker to perform and provides vastly superior, detailed images without the problem of superimposition. It also allows for visualization of areas inaccessible by endoscopy, provides guidance for biopsy procurement, and helps plan therapeutic strategies for fungal rhinitis (cribriform plate integrity) or neoplasia (radiation therapy). Disadvantages include availability and the need for general anaesthesia, although it is becoming more accessible and, with newer units, sedation may be possible. While cost can be a factor, the superior images obtained may lead to an expedited, cost-effective diagnosis.

Although CT provides a reasonably accurate differentiation between neoplastic and nonneoplastic disease in dogs, confirmation via biopsy should always be performed. Neoplasia is typically associated with a soft tissue density and extensive turbinate destruction, whereas normal to moderate destruction, with or without soft tissue densities, is more typical of inflammatory rhinitis. Fungal rhinitis is associated with extensive turbinate destruction and hyperlucency of the nasal passages. In cats, features overlap between nasal neoplasia and fungal rhinitis. Contrast enhancement may differentiate fluid from vascularized soft tissue, although it cannot determine the nature of the lesion.

(c) Magnetic Resonance Imaging (MRI)

Although studies show the ability of MRI to diagnose neoplastic versus inflammatory nasal disease, it is currently not the advanced imaging modality of choice. In dogs with nasal neoplasia or aspergillosis, studies have failed to demonstrate an advantage of MRI over CT. The lack of a mass effect was significantly associated with inflammatory disease and a mass effect along with vomer bone lysis, cribriform plate erosion, paranasal bone destruction, and invasion of the mass into the sphenoid sinus or nasopharynx was significantly associated with neoplasia. Disadvantages of MRI include prolonged anaesthesia due to the time required to obtain images, the expense, and availability compared to CT. In cases of undiagnosed chronic nasal disease, MRI may be of value.

(d) Rhinoscopy/Nasopharyngoscopy

The nasal cavities, nasopharynx, and, in some cases, the frontal sinuses can be directly visualized with endoscopic equipment. The procedures require expertise and moderately expensive equipment. Small rigid or flexible endoscopes provide adequate visualization of the nasal cavities. A flexible endoscope is required for access to the nasopharynx and frontal sinus, although sinuscopy may require trephination. Rigid scopes have better optics and are easier to manoeuvre, while flexible scopes are associated with less mechanical trauma to the tissue. Nasopharyngoscopy should be performed first, as haemorrhage from rhinoscopy may pool in the nasopharynx and impair visualization.

The procedure can be diagnostic (visualization of fungal plaques, foreign bodies, nasal polyps, mass lesions, nasal mites, nasopharyngeal stenosis) as well as therapeutic (removal of foreign bodies, fungal plaques, flushing/suctioning excessive secretions). It allows for biopsy procurement under direct visualization. Endoscopy was superior to nasal radiographs in achieving a diagnosis in dogs with persistent nasal disease. Evaluation of the choanae correctly identified nasal neoplasia in 26 of 34 animals where biopsies were obtained.

(e) Nasal Biopsy

Several biopsies from each nasal cavity should be procured from all dogs and cats with chronic nasal disease even if aetiology appears to be unilateral, is obvious (foreign body), or no apparent lesion is noted. Rhinoscope-guided biopsies are preferred, as visualization ensures that specific lesions are sampled.

Blind biopsy techniques can also be used, although in order to avoid inadvertent penetration of the cribriform plate, the clinician should measure the distance from the tip of the nose to the medial canthus of the eye and ensure the biopsy instrument does not pass this distance. A CT can determine the length the biopsy instrument must be advanced to reach the affected area. Biopsies may also be acquired via traumatic nasal flush or via rhinotomy.

Cytology of impression smears from biopsy samples may provide a fast tentative diagnosis. If Cryptococcus spp. is detected, serologic testing should be obtained to determine asymptomatic carriage from true infection (positive result) and to help monitor treatment. Haemorrhage (which can be life-threatening) and aspiration of blood are complications that should be expected.

What is treatment and outcome of sneezing and nasal discharge?

The diagnosis and treatment of nasal disease can be frustrating for both the veterinarian and pet owner. Despite a systematic and extensive investigation, an etiologic diagnosis remains elusive in many cases. More often, a descriptive diagnosis based on inflammatory infiltrates is provided (nonspecific rhinitis) with management based on symptomatic therapies to alleviate clinical signs.

Specific treatments are available for neoplasia, fungal rhinitis, foreign bodies, most congenital abnormalities, parasites, and dental disease. Prior to undergoing an extensive and costly investigation, educating the client of possible outcomes and the potential for lifelong management will help minimize unrealistic expectations and frustration.