Cat Coughing: Asthma, Heartworm, and When It Is an Emergency

A cough in a cat is a lower-airway problem until proved otherwise, and the commonest cause is asthma - an allergic narrowing of the small airways that Cornell puts at 1 to 5% of cats. This is an emergency and needs a vet now if any of these are true: Breathing with the mouth open, or panting like a dog; Crouched low to the ground with the neck stretched forward.

Is this an emergency?

Worst first. Find the highest rung that matches what you can actually see, and act on that one — not on the one you hope applies.

1. Emergency — go nowGo to an emergency vet or the nearest open clinic now. Do not wait for morning.
   • Breathing with the mouth open, or panting like a dog
   • Crouched low to the ground with the neck stretched forward
   • Gums or tongue that look blue, grey or very pale
   • Fast or heaving breathing while the cat is resting or asleep
   • Collapse, or a cat that has hidden and will not move

   Cornell describes the hunched body and extended neck as the posture many cats take during an asthma attack, and it is the single most useful thing an owner can learn to recognise. Do not delay to try a home remedy and do not force the cat into a carrier roughly - a cat in respiratory distress decompensates when handled, so the useful call is to the clinic first so they can take the cat straight to oxygen. Merck adds a second reason not to wait: in cats carrying adult heartworms, the death of even one worm can cause acute respiratory distress and shock that is sometimes fatal.

2. Same dayGet an appointment today. If your own practice is full, an urgent-care clinic counts.
   • Coughing fits several times a day, or a cough that is getting worse over days
   • A cat that has never coughed before and now does
   • Any audible wheeze
   • Coughing with lethargy, hiding, or a drop in appetite
   • A raised resting breathing rate that has not settled

   Cornell notes signs range from acute crises down to chronic low-grade coughing and increased respiratory effort, and that they can be brought on by light pressure on the throat. A cat that is coughing but not in distress still needs to be seen today rather than watched, because the same signs are produced by lungworm, by heartworm, and by pneumonia, and Cornell warns that drugs used for those conditions may do more harm than good in an asthmatic cat.

3. Routine — book an appointmentBook in the next few days and keep an eye out for anything on a rung above.
   • An occasional cough over weeks or months in a cat that is otherwise well
   • Coughing that appears at the same time each year
   • Coughing that follows a change of litter, a new candle, or building work in the house
   • Repeated 'hairball' episodes that never produce a hairball

   Book the appointment and take a phone video of an episode with you - Cornell notes there is no single test that diagnoses feline asthma, so the history carries real diagnostic weight. Cornell also lists vomiting among the signs of asthma, which is why a cat that hunches and hacks repeatedly without bringing anything up may be coughing rather than vomiting, and is worth filming.

4. Monitor at homeNo visit needed yet. Watch for anything on a rung above and re-read this page if it appears.
   • A diagnosed asthmatic cat that is stable on its inhaler or tablets
   • A cat in a household where someone smokes, with no signs yet

   The useful home measurement is the sleeping respiratory rate - count breaths over 30 seconds while the cat is asleep and double it, on a regular schedule, so a rise is noticed before a crisis. Cornell frames long-term management the same way: monitor respiratory effort, watch for coughing, and intervene with medication when the cat needs help.

Cats do not cough the way dogs do. A dog coughs at a dozen different problems; a cat that coughs is telling you something is wrong deep in the lung, in airways a few millimetres wide, and the commonest reason is asthma.

The hairball that never arrives

The crouched, hacking, retching episode that produces nothing is a cough, not a hairball. Cornell lists vomiting among the signs of feline asthma, which is exactly why the two are confused: the posture is similar, the noise is similar, and only one of them ends with something on the carpet.

Repeated "hairball" episodes that never produce a hairball are the single most commonly missed presentation of this disease. If it has happened three times this month and you have cleaned up nothing, it is a cough.

There is a second tell that costs nothing to check. Cornell notes a cough can sometimes be brought on by light pressure on the throat, which is a thing your vet will do in the consulting room rather than something to practise at home on a cat that is already struggling to breathe.

Film it. Cornell is explicit that no single test diagnoses feline asthma, so the episode itself carries real diagnostic weight — and cats reliably refuse to perform in an examination room. A ten-second phone video is worth more to the vet than your description of it.

Learn your cat's sleeping breathing rate

Count the breaths over thirty seconds while your cat is asleep and double it. Written down weekly, that number is the earliest warning this disease gives. Cornell frames long-term management the same way: monitor respiratory effort, watch for coughing, and medicate when the cat needs help.

Take it while the cat is genuinely asleep. A cat that has just been chased by a toddler is not a baseline, and a rate taken in a carrier is not one either.

What matters is the trend, not one reading. A rate that has crept up over a fortnight in a cat that looks fine is the version of this disease you can still treat in office hours — the alternative is the top rung of the ladder above.

Is it asthma, or is it heartworm?

Merck states plainly that the initial phase of feline heartworm infection is often misdiagnosed as asthma or bronchitis. Immature worms arriving in the pulmonary arteries provoke an inflammatory response that causes bronchitis and bronchoconstriction, producing a cough that mimics feline inflammatory airway disease.

This is not a technicality. Merck also states that heartworm infections are more often lethal in cats than in dogs, and that the death of even a single adult worm can cause acute respiratory distress and shock that is sometimes fatal.

The testing is imperfect and it is worth knowing why before you are quoted for it. Merck notes that cats which abort an immature infection have no detectable antigen, that cats with mature infections usually have none either because worm burdens are low, and that the antibody tests lack sensitivity. A negative result does not rule out current or past infection — it lowers the odds.

Dogs get the same parasite with a different presentation, and a cough in a dog has a longer differential list than a cough in a cat — that sorting problem is on our page about coughing in dogs.

Melarsomine, the adulticide given to dogs, is not recommended in cats at all, because of the risk of severe pulmonary inflammation and death. Feline heartworm is managed, not cleared. Merck puts the lifespan of the adult worms at two to four years, which is the only good news in this paragraph.

The cheapest tests are the ones that change the answer

A faecal examination is the least expensive item in the whole workup and it can end the diagnosis outright. Aelurostrongylus abstrusus — the commonest lungworm of cats, present in the US, Europe and Australia — is diagnosed from faeces because its larvae are coughed up, swallowed, and passed. Merck treats it with ivermectin or selamectin.

Set that against the alternative. A cat put on corticosteroids for presumed asthma is on them for life, and steroids are the wrong drug for a parasite. The faecal test and the heartworm panel cost a fraction of one round of chest radiographs and they are the two results that can move a cat off lifelong medication.

Cornell's own differential list is the argument for testing rather than treating: chronic bronchitis, lungworm, other parasites migrating through the lung, and infectious pneumonia all produce the same signs and similar test results as asthma. Cornell warns that the drugs used for those conditions may do more harm than good in an asthmatic cat, and the reverse is just as true.

A bronchodilator on its own is not treatment

Cornell is direct about this: bronchodilators are usually not used alone, because they do not treat the inflammation that causes the asthma. Merck says the same, listing them as adjunctive therapy and not sole therapy.

It matters because a bronchodilator works fast and visibly. A cat that breathes easier within minutes looks treated, and the airway inflammation underneath is untouched. That is how a stable asthmatic quietly becomes an emergency admission.

Merck lists inhaled fluticasone and budesonide as indicated for feline asthma, delivered through the aerosol chambers made for cats. Inhaled therapy puts the drug where the disease is and lowers the systemic steroid dose — and it is a recurring cost for the rest of the cat's life, not a course of treatment with an end date. Budget it like the lifelong monitoring a cat with kidney disease needs, because that is the shape of it.

Do air purifiers help an asthmatic cat?

Nobody has properly tested it in cats. Cornell recommends purifying indoor air and reducing allergens on the grounds that both help people with asthma, and says outright that these measures have not been rigorously tested in cats. That is a weaker claim than the marketing around air purifiers implies, and the honest version is worth having before you spend a few hundred dollars.

What Merck does support is removing the exposures: cigarette smoke, perfumes, pollens, moulds and dust. Those are free. No smoking indoors, no aerosols or plug-ins near the cat, low-dust litter, and vacuuming with the cat in another room cost nothing and target the same triggers a purifier is sold against.

What we can price here, and what we cannot

The cost section below is deliberately short, and you should know why before you read it. The real bill for a coughing cat is thoracic radiographs, sometimes bronchoscopy with airway sampling under anaesthesia, and then inhaled or oral medication for the rest of the cat's life. We do not yet publish researched price records for any of those three, and we are not going to invent them.

What we do price is the two visits that bracket the disease: the consultation where a stable cough gets worked up, and the emergency visit for a cat that is open-mouth breathing tonight. Those are real numbers, sourced and regional, and they are the beginning of the bill rather than the whole of it.

The other half of the honest answer is that this is a chronic bill, not an episode. Cornell describes feline asthma as often progressive, frequently failing to improve over time, and never truly curable — so the recurring line is the one to plan around, and the emergency visit is the line that appears when the recurring one has been skipped.

Treat the figures below as the floor. A cat whose cough turns out to be a blocked bladder problem rather than a lung one is a different page and a very different bill — urinary blockage in cats is the other feline presentation where posture, not noise, is the sign that decides how fast you move.

Why feline asthma and chronic coughing in cats happens

Allergic inflammation of the lower airways

Cornell: a susceptible cat makes antibodies to an inhaled allergen, and on re-exposure those antibodies recruit immune cells into the airways. The result is irritation, swelling, reactive constriction and mucus, which narrows the airway and makes it hard to move air. Merck describes the same process as airway hyperresponsiveness, airflow obstruction, airway remodelling and eosinophilic inflammation driven by IgE.

Inhaled irritants and aeroallergens

Merck names the exposures that matter in management: cigarette smoke, perfumes, pollens, moulds and dust. These are not the cause of the underlying allergy but they are the triggers an owner can actually remove, and they are the cheapest intervention on this page.

Heartworm

Merck: immature heartworms arriving in the pulmonary arteries provoke an intense inflammatory response that causes bronchitis and bronchoconstriction, producing a cough that mimics feline inflammatory airway disease. Merck states plainly that this initial phase is often misdiagnosed as asthma or bronchitis, and that heartworm infections are more often lethal in cats than in dogs.

Lungworm

Merck: Aelurostrongylus abstrusus is the most common lungworm of cats and is found in the US, Europe and Australia. Clinical signs are often absent, but chronic wasting, cough, dyspnoea and wheezes occur. Larvae are coughed up, swallowed and passed in the faeces, which is why a faecal sample belongs in the work-up of a coughing cat.

Chronic bronchitis and infectious lung disease

Cornell lists chronic bronchitis, lungworm, migration of other parasites into the lungs, and infectious causes of pneumonia as conditions that produce the same signs and similar test results as asthma. That overlap is the reason a coughing cat is worked up rather than simply put on steroids.

How a vet diagnoses feline asthma and chronic coughing in cats

Not every test below is run on every animal. Which ones are depends on what the examination finds, and each one is priced in the cost section further down.

Physical examination with resting respiratory rate and effort

Establishes whether this is a stable cough or an airway emergency, and listens for wheezes. Cornell notes coughing can sometimes be elicited by pressing lightly on the throat. What it costs

Thoracic radiographs

Cornell: in cats with asthma, radiographs often - but not always - show a bright branching pattern along the airways from accumulated inflammatory cells, and lungs overinflated by air trapped behind narrowed airways. A normal chest x-ray does not exclude asthma.

Bronchoscopy with airway cytology

Cornell: a flexible camera passed into the airways under heavy sedation or general anaesthesia, used to see the airway lining and sample the cells that line it. High numbers of inflammatory cells support asthma, though Cornell cautions the same cells appear in other respiratory diseases.

Heartworm antigen and antibody testing

Rules in the differential Merck says is routinely missed. Merck's caveat matters: cats that abort an immature infection have no detectable antigen, cats with mature adult infection usually have none either because worm burdens are low, and the antibody tests lack sensitivity - so a negative result does not rule out current or past infection.

Faecal examination for lungworm larvae

Aelurostrongylus larvae are coughed up, swallowed and shed in faeces, so a Baermann or flotation is a cheap way to find a treatable cause before a cat is committed to lifelong steroids.

How feline asthma and chronic coughing in cats is treated

Emergency stabilisation and oxygen

For the open-mouth-breathing or crouched cat. The first treatment is oxygen and minimal handling, before anything is put on the table. This is the visit that has to happen tonight. What emergency stabilisation and oxygen costs

Corticosteroids, with or without a bronchodilator

Cornell: veterinarians usually prescribe corticosteroids to reduce airway inflammation, with or without bronchodilators to widen the airways, and both come in oral, inhaled and injectable forms. Cornell is explicit that bronchodilators are usually not used on their own because they do not treat the inflammation that causes the asthma - Merck says the same, listing them as adjunctive and not sole therapy. What corticosteroids, with or without a bronchodilator costs

Inhaled therapy through a feline aerosol chamber

Merck lists inhaled fluticasone and budesonide as indicated for feline asthma, delivered through the aerosol chambers and inhaler systems made for cats. It puts the drug where the disease is and reduces the systemic steroid dose, and it is a recurring cost for the life of the cat rather than a course of treatment.

Removing the trigger

Merck: avoidance of environmental aeroallergens - cigarette smoke, perfumes, pollens, moulds, dust - must be considered in management. Cornell is honest about the limits: purifying indoor air and avoiding allergens are recommended because they help people, but they have not been rigorously tested in cats.

Parasite control and heartworm prevention

Merck treats lungworm with ivermectin or selamectin, and manages feline heartworm conservatively - melarsomine, the adulticide used in dogs, is not recommended in cats because of the risk of severe pulmonary inflammation and death. A cat with airway disease should be on a year-round preventive, which is the cheapest line here by a wide margin.

Outlook and prevention

Cornell is direct: feline asthma is often progressive, frequently fails to improve over time, and cats can never be truly cured, but with monitoring of respiratory effort and medication when it is needed, owners can keep an asthmatic cat comfortable for years. Flare-ups vary from mild to life threatening, and the life-threatening ones are why the emergency rung above is the top of this page. Where the cough turns out to be heartworm rather than asthma the picture is different again: Merck puts the lifespan of adult heartworms in cats at 2 to 4 years, so spontaneous recovery is possible, but also notes infections are more often lethal in cats than in dogs.

The allergic tendency itself cannot be prevented, but the exposures can be reduced: no smoking indoors, no aerosol sprays, scented candles or plug-ins near the cat, low-dust litter, and dusting and vacuuming without the cat in the room. Merck's avoidance list is the evidence base for all of it. Keep every cat on a year-round heartworm preventive - it is the only item on this page that prevents a fatal outcome rather than managing a chronic one. And learn the sleeping respiratory rate, because the earliest sign of a deteriorating asthmatic is a resting rate that has crept up.

How common it is: between 1 and 5% of cats — Cats generally; Cornell Feline Health Center's published estimate, not a counted cohort. Source.

What treating feline asthma and chronic coughing in cats costs

Costs for feline asthma and chronic coughing in cats run from $56 for routine vet checkup (wellness exam) to $150 for veterinary urgent care visit. A severe case can run past the top of that range — what treatment adds depends on how bad it gets.

Each block below is one procedure we price in full: the national range, the region-by-region table behind it, and how every row was sourced. Rows marked published come from a real price for that geography; rows marked indexed are the national range scaled by a cited regional cost index, and we label them rather than blending the two.

What the invoice for veterinary urgent care visit looks like

Veterinary Urgent Care Visit is the largest single bill on this page, so this is the one worth reading line by line. Clinics quote a bundled number and itemize afterwards; this is the decomposition.

Does pet insurance cover feline asthma and chronic coughing in cats?

Veterinary Urgent Care Visit is normally covered by a standard accident-and-illness policy. Unlike a wellness visit, an urgent care visit for an actual illness or injury is a normal illness claim under a standard accident-and-illness policy - subject to the annual deductible, the reimbursement percentage, any waiting period and any pre-existing-condition exclusion. The catch sits precisely on the number this page is about: several carriers exclude the examination fee itself while paying for everything done during the visit. Trupanion and State Farm both list examination fees, including specialist and emergency exam fees, among their exclusions; Healthy Paws covers everything but the exam fee; Figo sells exam-fee coverage as a paid add-on rather than including it in the base plan. So the $85-$150 that brought you through the door may be the one line your policy will not touch.

What you would get back: 70-90% of the covered portion after the annual deductible on a standard accident-and-illness plan. The exam fee itself is excluded by several major carriers, so expect reimbursement on the diagnostics and treatment rather than on the visit fee.

The catch, and it is the one that matters here: every US carrier excludes pre-existing conditions. If your animal has already been seen for feline asthma and chronic coughing in cats — or for signs a vet later links to it — a policy bought today will not pay for this episode. Cover is something you buy before the diagnosis, which is why the $56–$150 above is worth knowing while your pet is still well.

Waiting periods, and what each carrier counts as pre-existing, differ enough that the only useful answer is a side-by-side: our pet insurance comparison for veterinary urgent care visit shows which policies pay for it, how long the wait is, and how each one words the pre-existing exclusion.

Common questions

Related conditions and costs

What treating it costs, procedure by procedure

• routine vet checkup (wellness exam) cost $56–$130 — The annual physical examination a healthy dog or cat gets - vitals, ears, eyes, mouth, coat and skin - priced as the exam fee alone, before any test or vaccine is added to the bill.
• veterinary urgent care visit cost $85–$150 — A same-day visit for a problem that cannot wait for an appointment but is not life-threatening, priced between a routine exam and an emergency-room exam at every clinic that publishes all three.

Related conditions

• kidney disease in cat symptoms — The kidneys lose function slowly and permanently, and the cruel arithmetic is that they hide it until most of them are gone.
• signs and symptoms of cat diabetes — A disease in which the cat's cells stop responding properly to insulin, so glucose stays in the blood instead of feeding the body.
• why is my cat meowing so much — Excessive meowing is a sign, not a disease, and it is the sign this dataset can be most useful about — because its differentials range from a cat that has learned meowing produces breakfast to a male cat that cannot pass urine and will die within about two days without treatment.
• urinary blockage cat — A group of conditions causing painful, frequent, bloody or unproductive urination in cats.
• worm cat symptoms — Worms in cats are usually silent, and the signs owners are told to look for - a dull coat, a potbelly, vomiting, diarrhoea - are the same signs as a dozen other things.
• dog dementia treatment — An age-related degenerative brain disease that Cornell describes as causing deterioration similar to Alzheimer's disease in people, with beta-amyloid accumulating and neurons dying.
• dog colitis medication — Inflammation of the colon, which shows up as small, frequent, urgent stools carrying mucus and often fresh red blood, with straining.
• dog coughing — A cough is a sign, not a diagnosis, and the same dry hack can come from an infection that clears itself in two weeks or from a failing heart valve.
• dehydrated dog treatment — Dehydration is not a disease, it is the measurable consequence of one, and the numbers behind it are published rather than guessed.
• dog diabetic symptoms — The pancreas stops making enough insulin, so glucose stays in the blood instead of feeding the cells, spills into the urine and drags water with it.
• dog diarrhea — Loose or watery stool, with or without blood, and the sixth most frequently recorded disorder in dogs in primary practice.
• dog ear infection treatment — Inflammation of the ear canal, almost always with a yeast or bacterial overgrowth on top of it.
• dog pregnancy symptoms — The signs owners read as pregnancy - weight gain, a swollen belly, mammary enlargement, milk, nesting behaviour - are produced just as reliably by a false pregnancy, and there is no home test that tells them apart.
• dog UTI symptoms — A bacterial infection of the bladder, usually Escherichia coli travelling up the urethra from the perineum.
• dog vomiting and diarrhea — Sudden vomiting, usually with diarrhoea, from an inflamed stomach and intestine.
• dog vomiting blood — Blood in a dog's vomit - fresh red, dark clots, or the brown grit that looks like coffee grounds because the stomach has already digested it.
• dog eye allergies — A red, weeping, itchy eye is what owners call an eye allergy, and environmental irritants and allergens genuinely are, in Merck's words, common causes of conjunctivitis in all species.
• hip dysplasia in dogs — An inherited malformation in which the hip joint is too loose, so the ball grinds in the socket and arthritis follows.
• ivdd in dogs — A disc between the vertebrae ruptures or bulges and presses on the spinal cord, causing pain, wobbliness or paralysis.
• kennel cough in dogs — A contagious inflammation of the windpipe and airways caused by a mix of viruses and bacteria, not by one organism.
• dog limping — Limping means something painful is interfering with the normal use of a limb, and Cornell's framing is that it deserves veterinary attention rather than a wait-and-see.
• parvo in dogs — A virus that destroys the lining of a puppy's intestine and the bone marrow that makes its white blood cells, producing vomiting and bloody diarrhoea that can kill in days.
• dog seizures — A burst of abnormal electrical activity in the brain, which in its classic form drops the dog on its side with stiff, paddling limbs, frothing, loss of consciousness and often loss of bladder and bowel control.
• staph infection in puppies — Crusty pustules on a puppy's hairless belly and groin, caused by the dog's own resident bacterium overgrowing.
• dog wound treatment — Cleaning and closing a wound is mostly a timing decision, and the two things owners get wrong are both correctable in the first hour.
• dog skin yeast infection — Malassezia yeast lives on normal dog skin and only causes disease when something changes the skin it lives on.
• dog vomiting yellow — Yellow vomit is bile that has refluxed from the duodenum back into an empty stomach, and it is a description rather than a diagnosis.
• cat teeth disease — Three overlapping diseases, not one: gingivitis, which is reversible; periodontitis, which is not; and tooth resorption, in which the tooth dissolves from the inside out and which Cornell calls the most common cause of tooth loss in cats.
• symptoms of blocked anal glands in dogs — Two small scent sacs sit either side of the anus and normally empty when a dog passes a firm stool.
• dog skin allergies — A lifelong immune reaction to ordinary environmental substances - pollens, moulds, dust mites, dander - that shows up as itching rather than sneezing.
• worms in dogs — Four different worms with four different stories, grouped together only because they all live in a dog's gut.
• ringworm in dogs — Ringworm is a fungal infection of the hair and the surface of the skin, and the name is the first thing that misleads.
• yeast infection in dogs — Malassezia pachydermatis is a yeast that lives on normal dog skin and in normal ears.

Sources

Clinical sources

What this condition is, how it is diagnosed and when it becomes an emergency, from veterinary colleges, professional bodies and peer-reviewed primary-care studies.

1. Feline Asthma: What You Need To Know — Cornell Feline Health Center, Cornell University College of Veterinary Medicine, 2014.
2. Feline Bronchial Asthma — Merck Veterinary Manual, 2024.
3. Heartworm Disease in Dogs, Cats, and Ferrets — Merck Veterinary Manual, 2026.
4. Lung Nematodes in Small Animals — Merck Veterinary Manual, 2024.

Price sources

Where every figure in the cost section comes from. These are US fee schedules, published price surveys and carrier claims data — reported by us, and outside the scope of the clinical review noted at the top of the page.

1. Veterinary Exam and Procedure Costs, including 50-state routine visit tables — CareCredit (Synchrony), 2025-2026 Synchrony Average Procedural Cost Study conducted by ASQ360 Market Research, 2026.
2. Lack of online price transparency of small animal veterinary clinics in the United States — Adams, Gilley, Morris and Wisnieski, Frontiers in Veterinary Science, DOI 10.3389/fvets.2026.1788878, 2026.
3. About Our Pricing — Cane Bay Veterinary Clinic, Summerville, South Carolina, 2026.
4. Pricing and Transparency — Dallas Veterinary Clinic, Dallas, Texas, 2025.
5. Veterinary Clinic Price List — Tequesta Veterinary Clinic, Florida, 2026.
6. Philadelphia Pricing — Love City Vet, Philadelphia, Pennsylvania, 2026.
7. Pricing — Kenmore Veterinary Hospital, Kenmore, Washington, 2026.
8. Service Pricing — Covina Animal Hospital, Covina, California, 2026.
9. Price List — Midvalley Animal Clinic, Taylorsville, Utah, 2026.
10. Prices — Rocket City Mobile Vet, Huntsville, Alabama, 2026.
11. Pricing — Modern Animal, 2026.
12. Pricing Transparency — Animal Urgent Center, Ann Arbor, Michigan, 2026.
13. How Much Does an Emergency Vet Visit Cost? — CareCredit (Synchrony), 2025-2026 Synchrony Average Procedural Cost Study conducted by ASQ360 Market Research, 2026.
14. The Emerging Role of Urgent Care — MSPCA-Angell Animal Medical Center, 2026.