Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
Based on the signs you have reported for Isabella, I would be most suspicious that she may have caught an upper respiratory tract infection. These are very common among cats and especially those that live outside. Otherwise, just to note, we can also see sneezing/coughing with cats that have allergies, foreign bodies (ie seeds, grass) caught in the nose, bacterial tracheitis, fungal nasal infections, lung infections, or polyps/growths in the airway.
In regards ***** ***** to approach this for her, it will depend on whether she has any nasal discharge and what color it is. If you seen any snotty green/yellow discharge this would be a sign of bacterial infection and antibiotics from her vet would be indicated.
Otherwise, if we have a viral infection, then supportive care tends to be the mainstay. Now I appreciate she is an outside cat, but its not clear how easy to handle she may be. Therefore, I will outline some options; but which to use with her will depend on her. Therefore , to start since she is sneezing, you can take her in the bathroom while you run a hot shower. The steam will help loosen and clear some of the snot congesting her You can also use a baby nebulizer/humidifier, but often cats don’t like things held up to their faces (but you can often make little ‘steam tents’ with her in a cat carrier with these and a sheet).
If she is building up mucus that the steam isn't shifting, you can use a cotton ball moistened with warm water to wipe away crust and mucus. Furthermore, you can use saline nasal drops like Ocean Mist (but not anything medicated) to further reduce discharge build up. To do so, just tilt her head back and drop 2-3 drops in one nostril. Cats hate this, but it helps. After the drops go down, you can let the head up and wipe away any discharge that gets loosened. Then repeat with the other nostril.
Furthermore, if allergies are suspect for her and as it does have some decongesting properties, we can potentially trial her on an antihistamine. Most commonly we use Benadryl/Diphenhydramine for these cases (More Info/Dose @ http://www.petplace.com/drug-library/diphenhydramine-benadryl/page1.aspx). A low dose (ie. 0.25mg per pound of her body weight twice daily) can just be enough to reduce any allergic irritation for her We like to keep the dose low in cats, as they can have drowsiness with this medication (just like people). And of course, this medication shouldn't be used if your lass has any pre-existing conditions or is on any other medication without speaking to your vet.
As well, making sure she is getting food
and water is important, as congested cats who can’t smell their food often won’t eat as well as they should. Therefore, any decline in her normal appetite and we would want to consider tempting her with smelly wet foods (since they are high in water). It may help to warm it up a bit in the microwave to help her be able to smell it.
Finally, since feline herpes virus is a common lifetime infection that can cause all the signs you have reported (even the voice loss), you can consider trying her with L-lysine. This is a nutritional supplement that can help them recover quicker if this virus is present. This is available over the counter at pet stores, vets, online, and heath food stores. They tend to come as powders, gels, or crushable tablets that can be mixed into food. An average cat dose is 500mg a day.
Overall, we do have a few concerns for your Isabella's signs but flu is the most likely. Therefore, we would want to use the above for her at this point. Of course, if she doesn't settle or you see snotty discharge, then we'd want to have her checked by your local vet for further treatment.
I hope this information is helpful.
Please do let me know if you have any further questions.
If you have no further questions, feedback is always appreciated.
All the best,
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