Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Pulmonary fibrosis is scarring of lung tissue that makes it stiff and harder to breathe. It’s uncommon in cats and is usually seen in middle-aged to older cats. Signs include fast or labored breathing and reduced activity, which can look like asthma or heart disease. Diagnosis often requires a CT scan or lung biopsy. There’s no cure, and treatment focuses on comfort and slowing progression.
Signs
- Fast breathing at rest
- Labored breathing or open-mouth breathing (emergency)
- Coughing in some cats
- Tiring easily, weight loss
Conditions that look similar
- Feline asthma
- Heart disease and heart failure
- Lung tumors
- Pneumonia
- Fluid around the lungs
Diagnosis
- Chest X-rays
- Heart ultrasound to rule out heart disease
- CT scan
- Lung biopsy in some cases
Management
- Treating any secondary infection
- Anti-inflammatory medications in some cats
- Oxygen during breathing crises
- Keeping your cat calm, cool, and at a healthy weight
- Monitoring sleeping breathing rate at home
The outlook is often guarded. Your vet can help you monitor comfort and quality of life.
Sources
- Cohn LA, et al. Identification and characterization of an idiopathic pulmonary fibrosis-like condition in cats. J Vet Intern Med. 2004
- Merck Veterinary Manual: Respiratory diseases of cats
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.