Pinkeye in Cats: Causes, Symptoms & Cure – Catmart
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Pinkeye in Cats: Causes, Symptoms & Cure

You may have noticed that your cat has a runny and swollen eye. But are those symptoms caused by conjunctivitis, or a similar cat-specific condition?

Can cats get conjunctivitis? They can, and it’s similar to the conjunctivitis people get. Conjunctivitis is an issue that affects the conjunctiva, the membranous covering of part of the eye. This covering can become infected or inflammed by bacteria, viruses or environmental triggers. Symptoms include redness, swelling, irritation and discharge. As conjunctivitis can be a symptom as well as a standalone issue, you may also notice sneezing, a runny nose and lethargy. Treatment depends on the cause, but antibiotics help with bacterial infection. Talk to a vet.

Untreated conjunctivitis in cats is a serious health issue, and can lead to blindness or the loss of the eye. You should therefore take your cat to the vet as soon as possible. Treatment for conjunctivitis in cats comprises

Can Cats Get Conjunctivitis?

Cats can develop conjunctivitis in the same way that we do. It can either be a stand-alone health problem, or be related to a separate health problem, such as cat flu or feline herpes virus.

What Is Conjunctivitis?

Conjunctivitis is a kind of infection. It affects the eyes, specifically the ‘conjunctiva’, which is the membrane over the whites of the eye. While cats don’t have whites in their eyes like we do, they do still have this membrane, and it can get infected. These infections can be stand-alone infections, caused by bacteria entering the eye; they can also be the knock-on effect of other kinds of infection like cat flu or herpes virus. Poor health can also, in a general sense, make cats more susceptible to pink eye. It’s for this reason that you should talk to a vet, as they can identify the true cause of the issue.

Is Cat Conjunctivitis the Same as Human Conjunctivitis?

cat eye
Your cat’s eyes should look clear and healthy like these. Conjunctivitis causes pinkness and goop, like it does in people.

Cat conjunctivitis is the same health issue as conjunctivitis in people—in every sense.

Cat conjunctivitis can be caused by the same bacteria as cause pink eye in people. These bacteria aren’t species-specific, meaning they can affect any mammal including people and cats. And since mammalian biology is broadly similar across species, the effects of these bacteria are the same: runny eyes, redness and swelling, and so on.

Besides that, cat conjunctivitis affects the same part of the eye as ‘human’ conjunctivitis. Bacteria infect the conjunctiva, which both cats and people have. It may look different in a cat’s eye, but it’s still there, and can get infected in the same way. The outcome of conjunctivitis is more serious in cats, however. In severe cases, it can cause blindness and the loss of an eye. This is also possible in human cases, but it’s much rarer.

This raises the question: can you get pink eye from your cat? The answer is that you can. Since it’s caused by the same bacteria, if you get those bacteria in your eye, it will cause pink eye. This could happen after you examine your cat’s eye to see what’s wrong with it, or touch the goop coming from your cat’s eye. Or your cat could rub its eyes on things or on its paws and you could catch it that way. You should be careful to wash your hands frequently and avoid touching your eyes if your cat has pink eye.

What Causes Conjunctivitis in Cats?

Conjunctivitis in cats is caused by the same things as conjunctivitis in people.

Bacterial Conjunctivitis

Bacterial conjunctivitis is perhaps the most common kind. Microscopic bacteria get into the eye and multiply, feeding on skin flakes and any dead tissue around the scratch or wound that led them there.

The eye is a perfect place for bacteria to thrive. That’s because the eyeball is surrounded by fluid at all time, and is kept warmer than the environment, as are all body parts. Bacteria are mostly made of water, so can only reproduce quickly when water is present, as it is here. And warmer temperatures help bacteria digest the foods they eat, meaning they can grow and reproduce yet more quickly.

Viral Conjunctivitis

Viral conjunctivitis is much the same as bacterial conjunctivitis, only the infection is caused by a virus, not bacteria. Viral infection occurs for the same reasons as bacterial infection, i.e. when a viral load enters a wound. Viruses work slightly differently to bacteria, though: viruses enter cells and make them produce more copies of the virus, rather than reproducing by splitting like bacteria do.

There are key differences between viral conjunctivitis and bacterial conjunctivitis, though. One is that there won’t be any pus in the discharge that comes from the eye in the event of a viral infection. It’s also treated differently, because antibiotics work on bacteria, but not on viruses.

Allergic Conjunctivitis

Allergic conjunctivitis has the same symptoms as bacterial conjunctivitis, but has a different cause. It occurs when the conjunctiva becomes irritated not by bacteria, but by substances like pollen or dander. If your cat happens to be allergic to a substance like these, then its eye will become swollen and red just like a bacterial infection.

Cat Flu & Conjunctivitis

Conjunctivitis can also be a symptom rather than its own health issue.

In most cases in people, conjunctivitis is its own thing. It occurs on its own, not as a result of a deeper health issue. But in cats, it’s common for conjunctivitis to occur as a symptom of a wider, more serious health problem.

The most common is ‘cat flu’, which is wrongly termed—it’s more like a cold than a flu bug. Either way, cat flu causes many symptoms like sneezing and a runny nose, which you would expect. But it can also cause conjunctivitis, too, as the infection spreads to the eyes. The eyes will water slightly as they do in a typical respiratory infection, but in this case the problem can go beyond that, and become full conjunctivitis in its own right.

Pinkeye can result from other issues, too, like feline herpes virus. FHV can cause upper respiratory infection, too, but is specifically caused by this virus.

How Do I Know If My Cat Has Conjunctivitis?

Conjunctivitis has several obvious symptoms. These are similar to the symptoms of conjunctivitis that you see in people.

1) Pink or Red Eye

Conjunctivitis makes the whites of the eye pink or red, hence the common name pink eye.

The reason for this is that the infection specifically infects the conjunctiva. When the conjunctiva becomes infected by bacteria, the blood vessels in it dilate to allow more blood to the area. This gives the conjunctiva an overall pinkish or red appearance. The reason your cat’s body does this is that the blood contains germ-busting cells that will combat the infection; the more blood is sent to the area, the quicker the infection will be defeated.

Cats’ eyes aren’t white like ours are, but they still have a conjunctiva. This can become inflammed and pink-red in the same way as ours can. Despite the color of a cat’s eye being different, this pink-red color still stands out, so should be easy for you to spot and diagnose.

2) Swollen Eye

A related symptom of pink eye is that the eye will appear swollen.

Your cat’s eye may become so swollen that it doesn’t easily open. This is comparable to the swelling you get when you have a black eye, and you can hardly open it.

This happens because the blood vessels in the eye become dilated, i.e. bigger and wider and more blood is sent to the area. While each blood vessel will still be small, the overall effect of sending slightly more blood than usual is for the conjunctiva to swell. The point is that antibodies are transported in the blood—so more blood means more antibodies.

3) Irritated and Painful Eye

Both kinds of conjunctivitis—bacterial and allergic—cause pain and irritation. If you’ve ever had conjunctivitis, you’ll know just how painful and itchy it is.

You can spot this symptom from your cat’s behavior. It will scratch and paw at its eye, just like you might when you have conjunctivitis. This pain and irritation may also cause your cat to be irritable or even to lash out, either at you or at another cat.

What you may not know is that it’s actually your cat’s immune system that causes this response, not the infection. The swelling described above is triggered by the histamine response. Histamine is a hormone that the body produces and uses when it gets infected. It’s sent to the location of the infection to make it swell up, again so that more antibodies can get there.

The side effect of histamine, though, is that it causes a deep itching sensation. Histamine is what causes itching during allergic reaction, when the body goes into overdrive to fight off a perceived threat. In this case, the threat is real, but the result is the same either way.

4) Cat Eye Discharge

Another symptom of conjunctivitis is for discharge to come seeping out of the eye. This is another part of the body’s natural defense system. The idea is that the body will flush the area out with fluid, getting rid of anything that might be stuck in the eye and contributing to the infection. It will wash away some of the bacteria, too.

This discharge is known as mucopurulent discharge. That means it contains both mucus and pus. Mucus is a part of the fluid the body uses to flush bacteria away, but pus is a unique thick fluid that contains dead tissue, cells and bacteria. It’s produces specifically to fight infections. Large amount of pus can form underneath an abscess, but it can also be exuded slowly from wounds without getting trapped and forming a high-pressure spot. It seeps slowly from the infected area along with the rest of the discharge.

5) Corneal Ulcers

An ulcer is a small wound that has become infected. A corneal ulcer is one of these that occurs on the cornea, a part of the eye.

Cats experience small scratches on the eyes semi-frequently as a result of playing, fighting, or just exploring. They are especially likely to become infected when they are caused by another cat’s claw, because cats’ claws have bacteria on them.

A corneal ulcer isn’t a pleasant sight to see. It looks like a regular ulcer, except on the eye: a small whiteish crater that forms around a small wound. This whiteish spot can either have sharp boundaries, or blur into the rest of the eye.

6) Third Eyelid Infection

Your cat’s third eyelid is located underneath its other two. You can’t normally see it, but it’s the one that comes across when your cat is sleepy. Rather than moving from top to bottom or bottom to top, it moves across your cat’s eye to close it.

This eyelid can become infected in the same way as the conjunctiva can. It will become pink-red and swollen, too.

7) Sniffling and Sneezing

Many of the conditions that cause conjunctivitis also cause sniffling, sneezing and a runny nose. Chlamydophila, for example, can cause an upper respiratory infection—essentially a cold. If the bacteria get into your cat’s eyes as well, they cause conjunctivitis.

8) One or Both Eyes Affected

Pink eye can affect either one or both eyes.

Bacterial pink eye infections can spread from one eye to the other when the cat scratches and paws at the affected area. Or, the bacteria that started the first infection may come from an unclean environment, meaning that it could affect your cat’s second eye at any time. The same applies to allergic conjunctivitis. Irritants that travel through the air like pollen can float into both of your cat’s eyes.

If you notice the issue spreading from one eye to the other, then the issue is likely an infection. Your cat is rubbing at its eyes, and the discharge from them helps the bacteria or virus spread.

9) More Than One Cat Affected

Bacterial conjunctivitis is highly contagious. It can therefore quickly spread from one cat to another (provided you have more than one!) It can also affect more than one cat in your household if they both live in the same unclean conditions. Allergic conjunctivitis can also affect more than one cat.

It is possible for an infection to only affect one cat. But if your cat has had ‘conjunctivitis’ for a long time, and it hasn’t spread to your other cats despite them living and playing in close proximity, then it may be another condition altogether.

10) Symptoms Progress & Get Worse

If left untreated, the symptoms of pinkeye can progress and get worse—and cause much more serious eye problems than a basic infection.

Besides those described above, your cat may begin to lose its sight. This can occur because of pressure on the optic nerve because of swelling, or because of physical damage. The eye can continue swelling to the point that it’s much larger than the other, and can be clearly painful for the cat. It can get so bad that the best course of action is actually to remove the eye.

How Do You Treat Pink Eye in Cats?

As you’ll know if you’ve ever had conjunctivitis, treatment is not necessarily simple. That’s because pinkeye can have many different causes, and some causes cannot easily be identified or corrected.

Diagnosing Pink Eye in Cats (Talk To a Vet)

No matter how your cat is sick, you ought to take it to the vet. There are several reasons why:

  • Your diagnosis may be wrong. You may try to treat the conjunctivitis thinking it’s caused by bacteria, when it’s actually caused by pollen. This would mean that your treatment would be unsuccessful.
  • The vet has access to medications that are stronger than you can find over the counter, or that you can’t get over the counter at all.
  • They can identify the right kind of antibiotics for the bacteria causing the conjunctivitis (if applicable)
  • They can make recommendations on how to make your cat comfortable in the meantime

It may be tempting to not rack up a vet’s bill for a condition like conjunctivitis. However, conjunctivitis is a more serious health issue in cats than it is in people. You should therefore look to get it treated as soon as possible.

Eye Drops for Pinkeye in Cats

Treating pinkeye isn’t as easy as treating other health conditions in cats. That’s because it involves the use of eye drops, which are difficult to administer. There are two kinds of eye drops which you can get: those that are plain saline, and those which contain antibiotics.

The kind that contain antibiotics are only useful if the infection is caused by bacteria. Antibiotics don’t kill viruses, nor will they stop environmental irritants from causing conjunctivitis. But even regular eye drops can help. That’s because they flush out the eye, getting rid of some of the bacteria, cleaning any wound or flushing out any environmental irritants that may be present.

It’s next to impossible to administer eye drops to a cat on your own. That’s because the cat will try to get away from you, as it doesn’t enjoy the feeling of having the drops applied. It will likely lash out if you continue to force the issue without assistance. Have a family member, a friend or the vet keep the cat still with its head pointed upwards as you apply the drops.

Your vet may as an alternative offer an eye ointment for you to apply to your cat’s eye. The point isn’t to flush the eye out, but to provide a more long-lasting healing and antibacterial effect.

Other Medications for Conjunctivitis in Cats

You can also administer antibiotics in pill form. Your vet may prescribe these if it’s difficult or impossible to apply antibiotic eye drops. There are also antiviral pills your cat can take, but again, these should only be given if a positive identification of a viral infection has been made.

Other than this, there’s little that can be done to fight conjunctivitis. Your cat is relying on its body to heal the wound that caused the infection in the first place, and only once it has fully healed will the conjunctivitis finally be defeated.

How Can I Treat My Cat’s Eye Infection at Home?

You shouldn’t treat your cat’s conjunctivitis without any assistance from a vet, for the reasons described above. That includes the use of any home remedies, which don’t work as well as actual medication.

That being said, there are many things you can do to make your cat more comfortable, and to stop the infection from spreading. They include:

  • Dabbing your cat’s eyes occasionally with a Q-tip/cotton bud. This gets rid of some of the discharge around the eye, which can be smelly and make the fur wet.
  • Separating the cat from the other cats in the household. If the problem is a bacterial or viral infection, it can spread easily from one cat to another (in the same way that pinkeye spreads between children).

You should wash your hands both before and after you handle your cat. That’s because you could spread an infection to another cat, or catch an infection yourself.

How Long Does Pink Eye Last in Cats?

cat with glasses
With prompt treatment, your cat can be back to normal in no time.

The length of time that pink eye might affect your cat varies, but should be somewhere between one and two weeks. It depends on multiple factors.

One is whether the cause of the conjunctivitis is still present, e.g. if your cat has cat flu or herpes virus. The herpes virus, for example, stays in your cat’s system and flares up occasionally. Because the conjunctivitis is caused by a deeper issue than a simple scratch to the eyeball, it can last longer. The same applies to allergic conjunctivitis if the cause of the allergy remains present. This kind of conjunctivitis could be permanent without correction.

Conjunctivitis caused by a wound getting infected is different again. The length of time it takes for the condition to clear depends on how serious the wound is. A tiny scratch can heal up quickly, and the infection be gotten rid of similarly quickly. But a deep cut can take time to heal, and in the meantime, bacteria or viruses will enjoy entering the wound as they please. This can, then, take between a week and two weeks to clear up.

Lastly, conjunctivitis can be made to go away quicker if treated appropriately. Take your cat to the vet as soon as you can, and they can tell you how to get rid of it. Say for example that you have antibiotics left over from your cat’s last health issue, and you choose to administer them. These antibiotics may not be the right kind (as certain antibiotics are effective only for certain bacteria). Or, the cause may not be bacteria at all. You would therefore make the issue last longer than necessary by not treating it right; but a vet can identify the problem and determine the correct treatment.

Preventing Conjunctivitis in Cats

Prevention is better than cure, so once you get rid of the problem, you should take steps to stop it happening again.

Perhaps the best is to get your cat vaccinated. Vaccination can stop your cat catching feline herpes virus, one of the leading causes of pinkeye in cats. Stop the FHV, and you stop the pinkeye too. Vaccines are perfectly safe for cats; talk to your vet if you have any doubts.

You should also keep an eye on your cat as it plays and explores. This can help you identify how your cat damages its eyes, e.g. when play fighting with other cats, or scratching its eye on something in its environment. You can then take steps to stop that being an issue in the future.

Keeping your cat healthy in a general sense is also a good idea. Conjunctivitis gets particularly bad in cats with a poor immune system. Feeding the right food and allowing your cat lots of exercise help it ward off pinkeye on its own.

What to Do About Recurring Conjunctivitis in Cat

If your cat’s conjunctivitis won’t go away, that’s not good. It could continue to get worse, and your cat could go blind in one eye or lose its eye altogether.

One possible reason why is that you/the vet misidentified the cause, or that there are multiple causes. You should therefore talk to the vet again and get another diagnosis, or talk to another vet for a second opinion. Alternatively, you may not have been applying the eye drops correctly, so you can ask the vet about that.

You can also remove any possible causes of conjunctivitis from the home. These may be exacerbating the existing condition, making it reappear as treatment takes hold. If the cause is bacterial or viral infection, then keeping your cat’s environment cleaner may help. Your cat can pick up a large load of bacteria every time it uses its litter tray, for example; cleaning it out more often will help, as will washing it thoroughly before replacing the litter. Or, the problem may be environmental and allergic in nature, in which case you should remove the irritant from your home as soon as possible.

Hi! My name is Jamie Fallon. I run Catmart, an online cat health and cat behavior resource. If I'm not sat in front of my PC—and I usually am—then I'm either spending time with my cats or my other half... Whoever jumps on me or asks me for food first!

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