When to see a vet urgently
Breathing difficulties can quickly become life-threatening, so go to an emergency vet if:
- your cat breathes with an open mouth or breathing looks laboured;
- the tongue or gums turn bluish;
- your cat stretches their head and neck forwards to get air or cannot stay upright normally.
Find a vet near you and contact the practice. Do not wait for visible oxygen deprivation before seeking help.
Overview
A cat's lungs supply oxygen to the body and remove carbon dioxide. In pneumonia, inflammation affects the alveoli, bronchioles and surrounding tissue, leading to fluid accumulation and reduced lung function. Acute or chronic respiratory failure may result.
Alveoli are tiny air spaces through whose walls oxygen passes into the blood. Inflammation and discharge interfere with this exchange even if your cat tries to breathe faster. Pneumonia is not the same as heart-related pulmonary oedema or fluid in the chest cavity, however. These can cause very similar breathing difficulties but require different treatment.
During aspiration, material entering the lungs can also damage tissue chemically. The acidity of vomit, for example, irritates the lungs, and accompanying bacteria can cause infection as well. Inflammation may therefore occur without the disease having started as an infection caught from another cat.
Causes
Several factors can cause pneumonia in cats:
- Bacterial infections, for example Pasteurella multocida, Bordetella bronchiseptica, Streptococcus and Staphylococcus.
- Viral diseases, including herpesvirus and calicivirus, accompanied by a bacterial infection.
- Fungal infections, such as Aspergillus and Cryptococcus, more typically in immunocompromised cats.
- Aspiration of food, vomit or a foreign body into the airways.
- Parasitic diseases, which are rare, such as lungworms.
- Allergic and toxic reactions to inhaled smoke, toxic fumes or chemicals.
A lung infection can develop from an organism entering through the airways or from bacteria carried to the lungs in the bloodstream from inflammation elsewhere. Airway damage can also predispose to secondary bacterial infection. Investigations therefore often look for both lung changes and another disease that led to them.
Fungal infections can also occur without an identified immune deficiency. Their importance depends on factors including possible environmental exposure and the organism involved. The list of causes above describes several different forms of inflammation, and the same medication does not suit them all. A fungal infection, for example, does not resolve with an ordinary antibiotic targeting bacteria.
Risk factors
- Kittens and elderly cats.
- Cats with chronic viral infections, including FHV-1 and FCV.
- Immunocompromised pets.
- Animals that have recently had general anaesthesia, because of aspiration risk.
- Cats with neurological problems and difficulty swallowing.
Aspiration risk is particularly associated with situations in which swallowing or airway protection does not function normally. Incorrectly giving a liquid medicine or force-feeding can also cause material to be inhaled. Tell your vet if the symptoms followed vomiting, difficulty swallowing, general anaesthesia or coughing while medicine was given. Such an event can help target the investigation.
Typical symptoms
Symptoms of pneumonia include:
- A dry cough or one producing mucus.
- Breathlessness, rapid breathing and wheezing sounds.
- Nasal discharge, either watery or containing pus.
- Tiredness, loss of appetite and listlessness.
- Raised body temperature.
- Bluish mucous membranes (cyanosis) with severe respiratory failure.
- Weight loss with prolonged disease.
Not every symptom in the list has to occur at once. The vet assesses breathing effort and oxygen supply even when coughing is not the main sign you have noticed. Do not wait for fever or bluish mucous membranes before seeking investigation. Unusually fast or heavy breathing together with loss of appetite and weakness needs assessment.
Difficulty breathing alone does not confirm pneumonia. Other common causes in cats include asthma, pulmonary oedema associated with heart failure and fluid around the lungs. Owners find these difficult to distinguish by outward signs, and home treatment based on a wrong assumption can delay appropriate care.
Complications and consequences
Untreated pneumonia can lead to:
- Chronic respiratory failure.
- Lung abscesses.
- Pleuritis, with fluid accumulation in the chest cavity.
- Sepsis, involving infection spreading throughout the body.
- Death, particularly in kittens.
Lung tissue and the chest cavity around the lungs are different areas. Fluid can accumulate in the chest cavity for many reasons, and fluid alone does not mean an infection of the pleural space. If fluid is identified there, testing it may be needed to distinguish the cause.
Severe inflammation can also disrupt other organs' function. Inflammatory mediators originating in the lungs can affect the kidneys, heart and digestive tract, for example. A seriously ill cat may therefore need monitoring of the whole body as well as lung treatment. Treatment needs are not assessed solely by how much your cat coughs.
Diagnosis at the vet
Diagnosis is based on:
- A clinical examination and listening to the lungs.
- Chest X-rays, the main investigation.
- Blood tests showing an increased white blood cell count and signs of inflammation.
- Bronchoalveolar lavage to identify the organism involved.
- Bacterial culture to select appropriate medication.
- Chest ultrasound if needed.
Sampling and the urgency of treatment
Chest images look for changes consistent with inflammation, but the organism responsible usually cannot be identified from an image alone. An airway wash sample can be examined for cells and cultured for bacteria. Susceptibility testing helps choose a medicine effective against the bacterium found. Possible contamination of the sample is considered when interpreting results.
A sample is ideally taken before antibiotic treatment if your cat's condition allows. However, treatment of a seriously ill cat is not delayed while waiting for results. With severe breathing difficulties, breathing support may be needed before more demanding sampling. A result obtained later may change the medication initially chosen.
Blood tests help assess inflammation and other aspects of health, but clinical findings and imaging are needed alongside them. Investigations also look for a predisposing underlying disease. This is particularly important if pneumonia recurs or the response to treatment is weaker than expected.
Routes of transmission in infectious cases
- Direct contact with sick animals.
- Droplets from sneezing or coughing.
- A complication following viral infection.
Contagiousness depends on the cause. Aspiration itself is not an infection that spreads between cats. Calicivirus and certain respiratory bacteria, however, can spread between animals. A viral disease can also predispose to a later bacterial infection; a secondary complication does not mean every form of pneumonia spreads in the same way.
If several cats live at home or eye and nasal discharge have also occurred, mention this at the appointment. Respiratory infections are particularly important in dense cat populations. The practice can advise, according to the cause, whether your sick cat needs a separate space and how to monitor the others for symptoms.
Treatment and follow-up
Bacterial pneumonia is treated with an antibiotic chosen by the vet. In severe cases, medication begins according to the initial assessment and is refined when culture results become available. Another cause may require antifungal treatment, for example. In aspiration cases too, the need for medication is assessed according to inflammation and possible bacterial infection.
Oxygen is given if the lungs cannot maintain an adequate supply. Fluid therapy and nutritional support may also be needed in hospital. In some cases, nebulisation and other respiratory physiotherapy can help clear airway secretions. Their need and delivery are assessed individually; a cat with breathing difficulties is not treated with home steam alone.
Both breathing and general condition are monitored during treatment. Recovery usually includes the return of appetite and activity, but seeming brighter alone does not show whether lung changes have resolved. The vet decides whether repeat imaging and other checks are needed. Treatment duration is not inferred from the first better day.
At home, your cat needs a quiet, warm, dry environment. Watch eating, drinking and breathing at rest. Contact the practice if breathing becomes difficult, your cat will not eat or their general condition worsens again. Persistent symptoms may require reassessment of medication, an underlying disease or complications.
Prevention
- Up-to-date vaccination against viral infections, including herpesvirus, calicivirus and panleukopenia.
- Avoiding chilling, draughts and stress.
- Good nutrition and support for immune defences.
- Ensuring safety by preventing exposure to smoke or chemicals.
- Close monitoring after general anaesthesia and prompt care for conditions in which food or vomit may be inhaled, such as repeated vomiting or difficulty swallowing.
- Regular veterinary health checks.
Herpesvirus and calicivirus vaccinations reduce the risk of associated severe illness but do not prevent every infection or case of pneumonia. Panleukopenia vaccination prevents another disease; it is not a general pneumonia vaccine. Avoiding draughts alone does not prevent disease caused by an infectious organism or aspiration.
To help prevent aspiration, do not give liquid medicine faster than your cat can swallow. If swallowing is difficult or your cat is unusually drowsy, ask for advice before giving medicine or food by mouth. The safety of syringe-feeding also needs to be checked with your vet.
What it means for owners
Pneumonia in cats is a serious respiratory disease rather than ordinary cat flu. It requires prompt veterinary care, particularly for a cat in an at-risk group. The earlier treatment begins, the better the chances of recovery.
This text provides information only and does not replace veterinary treatment. If your cat develops symptoms, seek veterinary attention.
Frequently asked questions
Can a cat's pneumonia spread to other cats?
Any risk of transmission depends on the organism involved. Some respiratory infections can spread, but aspiration pneumonia itself is not contagious. The vet assesses whether special arrangements are needed to protect other animals.
Can pneumonia be treated at home?
Home care may be part of the plan once the vet has examined your cat and judged them stable enough. Difficulty breathing or oxygen deprivation may require hospital care. Do not try medication at home as a replacement for examination.
Why is a check needed if my cat already seems better?
A follow-up examination assesses whether lung inflammation is resolving and whether a continuing predisposing problem is present. Breathing, general condition and chest imaging where needed affect ongoing treatment. Do not stop prescribed medication or miss an agreed follow-up solely because your cat seems brighter.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Pneumonia in Cats, Merck Veterinary Manual, accessed 2026-11-02.
- Pneumonia in Dogs and Cats, Merck Veterinary Manual, accessed 2026-11-02.
- Pneumonia, Cornell University College of Veterinary Medicine, accessed 2026-11-02.
- Respiratory: Companion Animal Medical Guidelines, University of Melbourne, accessed 2026-11-02.
- Respiratory Infections, Cornell University College of Veterinary Medicine, accessed 2026-11-02.
- Dyspnea (Difficulty Breathing), Cornell University College of Veterinary Medicine, accessed 2026-11-02.