Definition of Feline Asthma
Asthma in cats, also referred to as allergic hypersensitivity, feline allergic bronchitis, feline bronchopulmonary disease (FBD), chronic obstructive pulmonary disease (COPD), asthmatic bronchitis, feline lower airway disease, extrinsic asthma, eosinophilic bronchitis and immune-mediated airway disease, is a common condition triggered by activation and overreaction of a cat’s immune system to something in the environment.
The substance that stimulates the asthmatic reaction is called an “allergen.” Different cats will react to the same allergen in a wide range of ways. In other words, one cat may develop asthma because it is allergic to a certain carpet deodorizer, while other cats in the same household may have no reaction to the same product.
Asthmatic cats typically have recurrent attacks of wheezing, sneezing, coughing and labored breathing due to their immune system’s response to the offending allergen, which causes their airways to constrict. Feline asthma is similar to bronchial asthma in people.
Primary Causes of Asthma in Cats
How Cats Get Asthma
Feline asthma is triggered by an allergic reaction to some environmental allergen which usually, but not always, is inhaled. Exposure to the allergen causes inflammation of the cat’s airways and constriction or narrowing of the smooth muscle associated with those airways. It also can cause mucus to build up inside the lungs. The allergen itself can be almost anything. Common inciting causes of asthma in cats include:
- Tobacco or fireplace smoke
- Air pollution (smog, smoke from wildfires or smoke from crop burning)
- Carpet cleaners and deodorizers
- Heartworm infection
- Lung parasites
- Hair sprays
- Room/air fresheners
- Kitty litter
- Home remodeling products
- Landscaping materials
- Grasses, weeds and other shrubbery
- Animal dander (new pets, kennels or veterinary visits)
Many other things can also trigger asthma. Indoor allergens that cause feline asthma tend to be present year-round, while outdoor allergens typically are more seasonal. Many times, the exact trigger of a cat’s asthma is never identified.
Prevention of Asthma in Cats
Most cases of feline asthma can be prevented by identifying and removing the inciting allergen(s) from the cat’s environment. Unfortunately, this is not always possible, particularly since in many cases the offending substance is never determined.
If removing the offending stimuli can’t be accomplished, the cat may require medical treatment and supportive care to relieve its symptoms. Fortunately, several types of prescription and over-the-counter drugs are available to help manage the symptoms that cats have from asthma, although medication won’t actually “prevent” the cat from having asthma, nor will it “cure” the condition.
Special Notes On Causes of Asthma in Cats
Feline asthma is fairly common in companion cats. The symptoms usually appear in young to middle-aged cats, but older cats can be affected as well. Because the signs of asthma mimic those associated with so many other respiratory disorders, the root cause of this condition can be difficult if not impossible to determine, despite extensive investigation and the best efforts of the cat’s owner and veterinary team.
Symptoms of Asthma in Cats
Effects of Feline Asthma – From the Cat’s Point of View
Feline asthma is a well-recognized medical disorder in domestic cats. The symptoms of this condition typically are episodic, which means that they come and go, or wax and wane, over time. Some cats have sudden or acute asthmatic attacks, while others develop symptom more slowly or chronically.
Asthma in some cats is fairly mild and doesn’t really seem to bother the animal, while other cats have severe and potentially life-threatening respiratory distress. Regardless of whether the symptoms of asthma come on quickly or slowly and whether they are mild or marked, all asthmatic cats will have some degree of trouble with their breathing.
Asthma – What the Cat’s Owner May See
Owners of cats with very mild or only occasional bouts of asthma may not even notice signs of the condition. In most cases, however, owners of affected animals will notice that something is wrong with their cat’s breathing.
The signs usually are most prominent when the cat exhales and typically can be heard easily by the owner or nearby people. These signs may include one or more of the following:
- Coughing (often sounds like the cat is “coughing up a hairball”)
- Labored breathing; difficulty breathing (dyspnea); comes on suddenly in acute cases
- Abdominal press when breathing out (exhaling); often visible
- Loss of appetite (inappetence; anorexia)
- Rapid breathing (tachypnea)
- Open-mouth breathing (panting; cats do not normally pant unless something is seriously wrong)
- Pale gums and other mucous membranes (pallor; cyanosis; caused by inadequate oxygen intake)
- Hunched shoulders (due to respiratory discomfort and distress)
These severe symptoms can also be seen in cats with pleural effusion and/or pulmonary edema, both of which frequently are associated with heart failure or other heart disease. When the consequences of asthma become this extreme – which is called “status asthmaticus” – the cat needs immediate veterinary attention. Status asthmaticus is a true medical emergency and should never be taken lightly or ignored.
Cats at Increased Risk
As a breed, Siamese cats seem to be over-represented among the large population of cats that have asthma. Parasitic lung infections are more commonly causes of asthma in cats living in the southern and mid-western United States, while heartworm as a cause of asthma is more prevalent in cats living in the South. Although asthma can affect cats of any age, it tends to be most common in middle-aged cats between 2 and 8 years of age.
Diagnosing Asthma in Cats
There is no single test that will conclusively confirm whether a cat is coughing, wheezing or having other breathing difficulties because it has asthma or some other respiratory condition.
The attending veterinarian presented with such a cat most likely will conduct a thorough physical examination and take a full history from the cat’s owner about its medical history and the onset and nature of its present symptoms. But further diagnostics will almost certainly be necessary to make a definitive determination as to the causes of the cat’s condition.
The veterinarian must rule out other disorders that could cause or contribute to the cat’s respiratory symptoms. These might include pneumonia, bronchitis, ingested hair balls, cancer, heartworm infection or lung parasites, among other things.
The results of routine blood work (a complete blood count and serum biochemistry profile) and a urinalysis typically are normal in asthmatic cats, although certain white blood cells called eosinophils may be elevated if heart or lung parasites are present.
Other laboratory tests, such as fecal flotation and heartworm testing, may be helpful if parasites are involved. Allergy tests, called intradermal skin tests, have not proven promising in helping to identify the cause(s) of asthma in cats.
Chest X-rays (thoracic radiographs) are extremely important when trying to diagnose the cause of feline asthma. Chest films can reveal inflammation, infection or scarring of the lungs, or they may be normal.
The presence, absence or severity of any radiographic changes does not always correlate with the seriousness of a cat’s asthma. An echocardiogram (ECG) can be used to detect heartworm infection or other possible heart involvement. This is a non-invasive test that most cats tolerate quite well, although sedation may be necessary to quiet the cat for this procedure.
Other, more advanced tests that may help to confirm or rule out feline asthma include transtracheal wash (TTW), bronchoalveolar lavage (BAL) and bronchoscopy. A urine evaluation can be done to assess the cat’s overall health and organ function.
The samples obtained through TTW, BAL and/or bronchoscopy are assessed microscopically through a procedure called cytology, where a veterinary pathologist or pathology technician analyzes the samples at a cellular level.
If abnormal levels of bacteria are found, they can be cultured (grown) in the laboratory so that an appropriate antibiotic can be prescribed.
Lung biopsy is also available, although it is rarely used in cats because it is so invasive and usually isn’t necessary. Sometimes, a positive response to treatment with medication will help to confirm a diagnosis of asthma, when other tests are inconclusive. Fortunately, feline asthma typically can be treated successfully, although it may require lifelong medical therapy.
Special Notes On Diagnosing Asthma in Cats
Owners should keep notes of when their cats show signs of asthma, and the nature and extent of those signs. This can be quite helpful to the cat’s veterinarian, especially if there is any seasonality of the cat’s symptoms that might be due to seasonal exposure to the offending allergens.
Treatment of Asthma in Cats
Goals of Treating Asthma in Cats
Owners of asthmatic cats can take comfort from the fact that there are a number of treatments available to minimize the symptoms and consequences of this disorder. The goals of treating feline asthma are to stabilize respiratory function, alleviate inflammation and remove the inciting allergens from the cat’s environment if possible. Of course, all of these goals are designed to make the cat as comfortable as possible.
Treatment Options for Cats with Asthma
Once asthma is diagnosed, the veterinarian will try to identify the underlying cause(s) of the cat’s allergic reaction. Owners are encouraged to keep an “asthma diary,” which records when the cat has an asthma attack, the severity of the attack and how long the attack lasts.
While it may seem burdensome, an accurate record of a cat’s asthmatic episodes can really help the veterinarian identify their asthmatic triggers. Cats with asthma should be treated aggressively in order to minimize long-term airway inflammation and chronic bronchial damage.
Cats with severe asthma attacks should be hospitalized until the crisis has passed. Sedation and administration of oxygen may be necessary to stabilize the animal. In emergencies, the veterinarian will probably administer one or more injectable medications to relieve acute respiratory distress.
A number of drugs can help reduce the number and severity of asthma attacks. Once the disorder becomes chronic, however, complete resolution may not be possible. The most common treatment protocol is to give corticosteroids to reduce inflammation. Bronchodilators will help inhibit airway constriction.
These medications both can be given orally or in an inhaled form. In the past, nebulizers were used to administer inhaled treatments to asthmatic cats. However, nebulizers are difficult to use on animals – especially on cats.
More recently, form-fitting metered-dose inhalers have become available. These inhalers are specifically designed to fit a cat’s muzzle and are especially helpful to administer bronchial dilation medications in acute situations.
Cats with asthma also often benefit from periodic oral anti-histamines. In cats with secondary bacterial infections, antibiotics that penetrate airway secretions may be recommended.
Incorporation of antibiotic therapy usually follows culture of airway samples. If the cat has heart or lung parasite involvement, anthelminthic drugs can be prescribed based on the specific parasite involved.
Finally, cough suppressants are available for cats suffering from prolonged or exhausting coughs. Antihistamines and cough suppressants are used cautiously in cats, because coughing is a helpful and normal mechanism for clearing airway secretions.
Environmental and life-style changes are also important. Cats with asthma usually limit their activity level on their own. Obese cats should be placed on a calorie-restricted diet under the supervision of a veterinarian.
Affected animals should be housed in a stress-free, clean, calm environment, preferably indoors, with a high-quality diet and free access to fresh water. In-house air filters can be helpful. Air conditioning and furnace filters should be changed regularly.
The prognosis for asthmatic cats ranges from good to grave, depending on the severity of their disease. If the inciting allergen can be identified and avoided or removed, the prognosis is good. Life-long treatment will be necessary in most other cases. Some cats don’t respond well to treatment and have a much more guarded prognosis.