Yes, domestic cats can get sinusitis (a sinus infection). They have two frontal and small wedge-shaped sinuses. Secondary infections (bacterial infections) of the frontal sinuses occur quite a lot because URI (upper respiratory infections) are common in cats.
The signs of feline sinusitis are:
- sneezing and snuffling
- a purulent discharge from the nose which is often from one nostril (purulent means a pus)
- the cat sitting with her eyes partly closed and her head hanging indicating a headache
- reduced appetite
- weight loss
- Sometimes an abscessed tooth (probably a top premolar) can lead to sinusitis. There will be a painful swelling under the eye.
Sinus infections can also be caused by a fungal infection: aspergillosis and cryptococcosis. The latter can cause a facial deformity together with ulcers of the nose and skin. It can be caused by the dust of pigeon excreta blowing into the home via an open window.
Feline sinusitis is confirmed by X-ray which will show an increased density in one sinus.
Humans have exactly the same problem: a viral infection causing a secondary bacterial infection of the sinuses. People can do certain things to minimise the chance of getting a ‘cold’. I don’t know of well publicised proactive steps to try and stop cats getting colds. Is it fair to say that more could be done to reduce the risk of a domestic cat getting a cold and therefore sinusitis.
Source: page 228 of third edition of the Cat Owner’s Home Veterinary Handbook. ISBN 978-0-470-09530-0
BACTERIAL INFECTIONS – SOME EXAMPLE PAGES: