Feline asthma is relatively rare but it is not normal for cats to cough. Sometimes they cough from throat irritation or to dislodge foreign objects but a cat that coughs regularly should always be checked out by the vet. Asthma in cats is an immune system in overdrive that causes chronic inflammation within the airways. The bronchioles become narrower from inflammation and eventually, a cat struggles to breathe.
Asthmatic cats mostly cough at night but with severe asthma, coughing can become constant. Cats that place their heads low, parallel to the floor, when they cough are more likely to be coughing from lung irritation than throat irritation. To properly diagnose asthma, X-rays of the lungs must be taken and the only real treatment is steroids (cortisone), to reduce inflammation. Cortisone can be given as long-acting injections, in pill form or, more recently, inhalers have been developed for cats to use. It is much safer to use inhalers as long-term use of steroids will cause a cat to develop diabetes.
My cat had asthma and in those days, inhalers weren't available and the only treatment we could give her was long-term cortisone injections. It also helps not to use solvents or aerosols in the house, as these can really irritate a cat's lungs. I found that when I moved out of the industrialised zone I was living in, she was much better and she only needed injections 3 or 4 times a year. As she got older, her asthma got worse and when she was 10, she started needing injections on a monthly basis. After 2 years of monthly injections, she developed diabetes and I was left with no choice: to discontinue asthma treatment in order to treat the diabetes would have left her unable to breathe so I had to make the heartbreaking decision to say goodbye to her.
My cat Tom also has mild asthma because his immune system has been damaged by the feline herpes virus but fortunately, his coughing isn't severe and he can be managed with Omega 3 supplements and doesn't need cortisone. Salmon oil has a powerful anti-inflammatory action in cats and can be used to manage milder cases of asthma. Although it was recommended to use Omega 3 for my first cat, I was supplied with hemp oil, which is a plant based form that cats can't utilise, they can only use fish oils effectively. I really wish that I had known that when my first cat was diagnosed