CONDITION

Chronic Upper Respiratory Disease in Cats

Why this matters now

Chronic upper respiratory disease in cats often develops as a sequel to acute viral infections acquired early in life, particularly feline herpesvirus-1 and feline calicivirus. These initial infections may occur during kittenhood, in shelter environments, or through contact with carrier cats. The acute phase typically resolves within two to three weeks, but the viruses — particularly herpesvirus — can establish lifelong latent infections in the trigeminal ganglia. Reactivation may occur during periods of stress, immunosuppression, or concurrent illness, leading to recurrent episodes of upper respiratory signs throughout the cat's life. Environmental stressors such as changes in housing, introduction of new cats, boarding, or veterinary visits can trigger viral reactivation and flare-ups of clinical signs.

The progression of chronic upper respiratory disease varies considerably between individual cats. Some cats experience only occasional mild episodes of sneezing and nasal discharge that resolve spontaneously within days. Others may develop progressively worsening chronic rhinosinusitis with persistent nasal congestion, mucopurulent discharge, and secondary bacterial infections that become increasingly difficult to manage. Over time, the chronic inflammatory process can damage the delicate nasal turbinate structures, creating altered nasal architecture that predisposes to bacterial colonisation and biofilm formation. This turbinate destruction is largely irreversible and can establish a self-perpetuating cycle where structural changes promote infection, and infection promotes further structural damage. Some cats develop chronic sinusitis with thickened sinus walls and impaired mucociliary clearance that maintains the disease process even between viral reactivation episodes.

Signals & patterns

Early signals

Intermittent sneezing episodes

Periodic bouts of sneezing that may occur in clusters, often triggered by stress, environmental changes, or seasonal factors. The sneezing may produce clear or slightly cloudy nasal discharge and typically resolves within a few days during early stages.

Mild nasal discharge

Clear to slightly cloudy discharge from one or both nostrils that may be most noticeable after the cat has been sleeping or resting. The discharge may be intermittent and relatively easy to miss, particularly in cats that groom frequently.

Occasional eye watering

Mild serous ocular discharge or increased tear production that may accompany sneezing episodes. The eyes may appear slightly watery or the periocular fur may show staining from excessive tearing, particularly in light-coloured cats.

Audible nasal congestion

Subtle changes in breathing sounds during rest or sleep, including mild stertor or snuffling sounds that indicate some degree of nasal passage obstruction. The cat may occasionally breathe through its mouth briefly during episodes of congestion.

Later signals

Persistent mucopurulent nasal discharge

Thicker, yellowish or greenish nasal discharge that persists between episodes and does not fully resolve. The discharge may crust around the nostrils and the cat may show reduced grooming of the face due to discomfort or chronic malaise.

Chronic open-mouth breathing

More frequent or sustained periods of mouth breathing due to significant nasal obstruction. The cat may resist physical activity, show reluctance to eat normally, and display visible distress during episodes of complete nasal blockage.

Reduced appetite and weight loss

Progressive decline in food intake related to impaired olfaction from chronic nasal congestion. Cats rely heavily on smell to initiate eating behaviour, and chronic nasal obstruction can significantly reduce food appeal and lead to gradual weight loss.

Facial deformity or asymmetry

In severe cases, chronic infection and inflammation may produce visible swelling over the nasal bridge or frontal sinuses, or asymmetry of the face related to unilateral disease progression or bone involvement.

Click to read about the biological mechanisms

How this is usually investigated

Investigation of chronic upper respiratory disease in cats typically begins with a thorough history and physical examination, assessing the duration, pattern, and character of clinical signs. The approach may progress from less invasive assessments to more detailed imaging and sampling depending on the severity and chronicity of the condition.

Physical examination and history review

Purpose: To assess the character and distribution of nasal discharge, the presence of facial asymmetry, oral health status, and overall body condition. The temporal pattern of signs, vaccination history, and known exposure to other cats provide important context.
Considerations: Differentiating between unilateral and bilateral disease can help narrow the list of possible causes. Unilateral disease may suggest foreign body, dental disease, or neoplasia, while bilateral disease is more typical of chronic viral-associated rhinosinusitis.

Skull radiography or computed tomography

Purpose: To evaluate the extent of turbinate destruction, sinus involvement, and the presence of fluid or soft tissue density within the nasal passages and sinuses. CT provides significantly more detailed assessment of nasal architecture than radiography.
Considerations: Advanced imaging requires general anaesthesia, which adds procedural considerations. CT is considered the imaging modality of choice for feline nasal disease, as it can reveal turbinate lysis, sinus opacification, and bone involvement that may not be apparent on radiographs.

Rhinoscopy and nasal biopsy

Purpose: Direct visual examination of the nasal passages allows assessment of mucosal condition, identification of masses or polyps, and targeted biopsy collection. Rhinoscopy can also identify foreign bodies that may not be visible on imaging.
Considerations: Rhinoscopy requires specialised equipment and general anaesthesia. The nasal passages of cats are narrow, limiting the size of endoscope that can be used. Biopsy samples help distinguish between inflammatory, infectious, and neoplastic causes of chronic nasal disease.

Bacterial culture and sensitivity

Purpose: To identify the bacterial species involved in secondary infection and determine which antimicrobials may be effective. This is particularly relevant for cats with mucopurulent discharge that has not responded to empirical antibiotic therapy.
Considerations: Interpreting nasal cultures can be challenging because the nasal passages harbour a normal commensal bacterial population. Deep nasal cultures or samples obtained during rhinoscopy may be more representative of the pathogenic organisms than superficial nasal swabs.

Viral PCR testing

Purpose: Polymerase chain reaction testing of nasal or conjunctival swabs can detect the presence of feline herpesvirus-1 or calicivirus nucleic acid, helping to confirm viral involvement in the disease process.
Considerations: A positive PCR result confirms the presence of viral genetic material but does not necessarily indicate active viral replication, as latent herpesvirus DNA may be detected. Negative results during quiescent periods do not rule out latent infection. The clinical significance of a positive result must be interpreted alongside the clinical picture.

Options & trade-offs

Management of chronic upper respiratory disease in cats is typically long-term and aims to control clinical signs rather than achieve cure, particularly when irreversible turbinate damage has occurred. The approach often involves combining environmental modifications, supportive care, and medical interventions tailored to the severity and pattern of the individual cat's disease.

Environmental and stress management

Minimising stressors that trigger viral reactivation can reduce the frequency and severity of flare-ups. This may involve maintaining stable routines, providing environmental enrichment, managing multi-cat household dynamics, and minimising changes in the cat's environment where possible.

Trade-offs: Environmental modifications address a root trigger but may not be sufficient to control signs in cats with established structural damage. The degree of stress reduction achievable varies with the cat's living situation and temperament.

Systemic antimicrobial therapy

Antibiotics targeting secondary bacterial infection can reduce mucopurulent discharge and associated discomfort during flare-ups. The choice of antibiotic may be guided by culture and sensitivity results, particularly for recurrent or refractory infections.

Trade-offs: Antibiotics address secondary bacterial infection but do not treat the underlying viral or structural components. Repeated or prolonged antibiotic courses raise concerns about antimicrobial resistance. Improvement during antibiotic therapy may be followed by relapse after discontinuation if the underlying structural and viral factors persist.

Antiviral therapy

Antiviral medications such as famciclovir may be used during herpesvirus reactivation episodes to reduce viral replication and shorten the duration of clinical signs. Topical antiviral therapy may be used for associated ocular disease.

Trade-offs: Antiviral therapy can help manage acute flare-ups but does not eliminate latent virus. The evidence base for systemic antiviral efficacy in feline herpesvirus varies, and cost and duration of treatment are practical considerations. Antiviral therapy is most useful during active viral shedding episodes rather than as continuous long-term management.

Nasal flush and topical treatments

Saline nasal flushing under anaesthesia can physically remove accumulated mucus, debris, and bacterial biofilms from the nasal passages, providing temporary relief from congestion. Nebulisation with saline may be used at home to help maintain nasal moisture and facilitate mucus clearance.

Trade-offs: Nasal flushing provides symptomatic relief but typically requires repeated procedures as mucus and bacteria re-accumulate. Home nebulisation requires cat cooperation, which varies considerably between individuals. The benefit is temporary but can significantly improve comfort during acute episodes.

L-lysine supplementation

Lysine has historically been suggested as a supplement to reduce herpesvirus replication, based on the theory that it competes with arginine, an amino acid essential for viral replication.

Trade-offs: The evidence supporting lysine supplementation in cats has been increasingly questioned, with several studies suggesting no benefit and potential harm at high doses. Current veterinary consensus has moved away from routine lysine supplementation, though it remains widely available and some practitioners continue to use it.

Common misconceptions

Misconception:

"Chronic sneezing and nasal discharge in cats is just a cold that will eventually resolve on its own."

Reality:

Unlike the self-limiting upper respiratory infections commonly seen in humans, feline upper respiratory disease can establish a chronic, lifelong condition. Herpesvirus establishes permanent latent infection, and the structural damage to nasal turbinates from repeated episodes may be irreversible. While some cats have only mild intermittent signs, others develop progressively worsening chronic rhinosinusitis that requires ongoing management.

Misconception:

"Antibiotics will cure chronic upper respiratory disease in cats."

Reality:

While antibiotics can help manage secondary bacterial infections that contribute to mucopurulent discharge and discomfort, they do not address the underlying viral infection or the structural changes to the nasal passages. Chronic upper respiratory disease is typically managed rather than cured, and the approach usually involves multiple strategies addressing different aspects of the disease process.

Misconception:

"A cat that has been vaccinated against upper respiratory viruses cannot develop chronic respiratory disease."

Reality:

Vaccination against feline herpesvirus and calicivirus reduces the severity of clinical signs but does not prevent infection entirely. Vaccinated cats can still become infected, develop latent herpesvirus carriage, and experience chronic respiratory signs. Vaccination is most effective at preventing severe acute disease but offers less protection against chronic carriage and recurrent mild episodes.

Understanding the pattern of a cat's respiratory signs — whether they are truly chronic and persistent or episodic with identifiable triggers — can help frame expectations for management. Noting the character of nasal discharge (clear versus coloured, unilateral versus bilateral), the relationship between episodes and identifiable stressors, and whether signs have been progressively worsening provides useful context. Maintaining the cat's nutrition is particularly important, as nasal congestion can significantly reduce appetite through impaired olfaction, and warming food or offering strongly aromatic options may help maintain food intake during flare-ups.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS