Since I just wrote a post on some of the common ailments that can affect cats, I thought it might be helpful to tell you what signs to watch for in your cat. How can you tell if your cat is sick? It isn’t always easy.
You will see in my list of references at the end of this post that I used five total, to research this article. Every one of them gives one piece of advice that is unchanging: If you think your cat is sick, but don’t know for sure, take the cat to your vet.
It’s not always a good idea to diagnose and treat on your own unless it’s a condition you and the cat have dealt with before. Even then, if your cat becomes extremely ill, it is wise to share with your vet to make sure you are following the best treatment plan.
One other piece of advice I found in a couple of articles, and that was to look into pet insurance. A few months ago, I wrote a post about pet insurance. Click on the blue highlighted “pet insurance” to take you to that post. Also, check the link at the bottom of this post. I just learned of a new pet insurance company that may be just what the doctor ordered. (Update: Still waiting to hear from the company. Will put up link as soon as it is available.)
Part of the reason cats hide illness has to do with their wild origins. They have an instinct to protect themselves from predators or from other cats that might be a threat. Our domesticated house cats still have the same tendency to avoid being vulnerable to any threat.
One very interesting reason why cats are less likely to show pain or illness: They have no emotional relationship with their discomfort. If they are in pain, they tend to accept that or an illness as the new normal, and then deal with it as best they can.
For this reason, we human companions are often the last to know that our fur baby is sick.
A couple of important signs of illness were also covered in the last post, and can be indicative of a number of problems. One of these is vomiting and one is diarrhea.
It is not normal for your cat to vomit. If the cat rarely vomits or is just ejecting a fur ball, that’s one thing. Anything more, and it may be the sign of a more serious condition.
Diarrhea might simply come from something the cat ate, or it may be due to parasites. The condition needs to be treated. If ignored, diarrhea can lead to dehydration and a worsening of intestinal inflammation. Besides, it is certainly not a condition your cat enjoys.
Either loss of appetite or an increase in appetite could be another concern. If your cat skips an occasional meal bet eats normally most of the time, watch the cat closely. If the cat stops eating entirely or only eats small amounts, you need to figure out why.
Often this question requires input from a vet to figure out the problem. If the cat doesn’t eat for even a few days, it could lead to a serious problem: fatty liver or hepatic lepidosis.
Increased appetite is also a concern, and could lead to a serious problem. Often, when this increase occurs in an older cat it is the sign of hyperthyroidism. At the very least, it could lead to overeating and obesity.
Weight change can also be a concern, whether either a gain or a loss. This could be an underlying health problem. It’s a more urgent problem if it is weight loss. Weight gain can become a problem over time.
How about kitty’s energy level? If the cat seems lethargic; if he’s sleeping more than usual, there 
might be an underlying health problem.
Increased thirst can be an indication of a problem. Usually, it’s with the kidneys or urinary tract. If your cat is drinking more water than usual, you’d best figure out why.
It is also important to notice changes in the cat’s urination. Changes could indicate a problem in the urinary tract or a kidney problem. Watch for any of these signs: Change in frequency or quantity of urine, using inappropriate spots, blood in the urine. Make a vet appointment.
If your cat is straining to urinate, but nothing is coming out, it could be an emergency, especially if it is a male cat. (See my story about my cat, Carlos, in my last post.) Bring the cat to the vet right away.
If your cat is not breathing normally (rapid breathing, shortness of breath, raspy breathing) you may need to go to an emergency clinic. If signs are mild, see your regular vet as soon as you can.
A possible upper respiratory infection may be indicated by discharge from the eyes or nose. Such a condition can make your cat feel ill and stop eating. This infection can be contagious to other cats in your home. There may be medication that will help.
Ear problems can be due to an ear infection or parasites such as ear mites. Don’t wait to deal with this problem because it can lead to an infected eardrum.
Sometimes increased vocalization can mean your cat is sick or in pain. It’s possible kitty is just bored, but best to rule out health problems first.
Skin irritation or hair loss could be caused by allergies, external parasites, or some other skin 
condition. It may be painful or itchy, so ask your vet for a remedy.
Overgrooming can be caused by a skin issue or pain. It is also related to stress. Before I brought Pogo cat home, he had been in a shelter for 7 1/2 months. A timid cat to begin with, the shelter really frightened him.
For one thing, the dogs at one end of the building never shut up. That was enough to stress him, right there. Consequently, when I got him, he’d pulled all the fur off his stomach and in lines down his legs.
His ears were like parchment — all the fur was off them. It took a while for it all to grow back. For the first few months, he must have dreamt about the place, because he’d start overgrooming, half-asleep. When he did so, I’d talk to him and stroke him, until he’d relax again and go back to sleep.
If your cat suddenly shows extreme personality changes, it could be due to a physical problem. It’s especially urgent to have him checked if he seems confused or disoriented.
Limping or trouble with jumping could be signs of an injury or arthritis. Even though your cat might be eating okay or acting normally, he could be in pain. You need to find out the proper treatment and move ahead accordingly.
When I brought Pogo home, it soon became apparent that he had arthritis. He limped and moved slowly. He wouldn’t run. (Now he does; as I write this post, he is chasing a little “pillow” filled with catnip around the living room.)
I live in a very small town, about a 35-minute flight to Juneau. I do not take Pogo in to Juneau unless it is absolutely necessary, as he stresses a great deal from the trip. So, what’s to do?
I take CBD oil for my arthritis, and online sources say it can be helpful for cats. A California friend makes CBD from hemp plants that are very low in THC (That’s what makes you high, and it is not good for cats.) So, I started giving drops to the cat.
It’s been very helpful. Also, he likes it. I put two or three drops in a little saucer and he laps it up. Since there is no vet here, I’m glad this solution worked.
Does your cat have a swelled spot on any part of his body? It could be a wound that has abscessed, 
or it could even be a tumor. Can you tell if it painful? Is it hot to the touch? If there’s no improvement in a day or two, see your vet.
Bad breath signifies dental problems. With mild halitosis, it’s important to get those teeth checked. Severe bad breath could be the indication of a serious problem.
Watch for excessive drooling and bleeding from the mouth. An oral infection exposes the cat’s whole body to the bacteria in his mouth. Such exposure could lead to problems with the heart or other organs.
Very often when a cat is sick, he will become withdrawn and may hide somewhere. On the other hand, he may become more demanding of attention. Or, he may just get cranky.
He will probably sleep more because his energy level is low. He won’t be interested in playing. He may not be grooming himself well, so you can see a change in the appearance of the coat.
As a summary, perhaps this list of five signs your cat may be sick would be a good one to keep in mind. These are all indications that it’s time to call your vet:
1) Undergrooming or overgrooming; increased shedding
2) Weight loss or weight gain
3) Problems with eyes or ears
4) Bad breath
5) Behavioral changes
Remember, too, if your cat is purring, it may not be because he’s happy. Cats also purr when they are sick or in pain. Purring is a good thing, because it helps the cat to heal, but the problem may need something more than a purr to alleviate it.
Here are the references I used for this article:
vcahospitals.com/know-your-pet/recognizing-signs-of-illness-in-cats
aspcapetinsurance.com/resources/5-signs-your-cat-is-sick/
thesprucepets.com/signs-your-cat-is-sick-4165142
olddominionanimalhospital.com/how-to-tell-if-your-cat-is-sick-7-symptoms-to-watch-out-for