Feline Herpes Flare Up – Symptoms and Treatment

The medical term for feline herpes is feline viral rhinopneumonitis (FVR) or feline herpesvirus type 1 (FHV-1).  It is also known as cat flu or cat herpes.  It is a virus that is prone to a feline herpes flare up.

What is a feline herpes flare up?

A flare up is when the herpes virus goes from the dormant stage to the active stage and symptoms start to appear.

How long does a flare up last?

All three of my cats have feline herpes.    When Zoli entered the family he had gotten it from his mother (a known stray in the area) and passed it along to Feri and Gyula. Since Zoli already had it, I didn’t know what to expect when Feri 20160301_082712and Gyula contracted it. All I know is the vet said that they would be sick and lethargic for a couple of weeks. That was kind of an understatement.

Feri got it first and was sick for about 2 weeks. He sneezed and slept a lot. Gyula got it near Feri’s tail end of the disease and he was sick for almost a month. I could tell he was achy and miserable. So the symptoms mimicked the flu for us.

If I catch a flare up quickly, it may go away within 24 hours.  If I do not, then it’s usually 3 to 4 days.  They aren’t as terribly sick as when they first got the virus.  Now, it is more of sneezing and watery eyes.

Is the feline herpes virus contagious?

Yes and no. Feline herpes virus is not contagious to humans so you or I can’t get it. However, it is contagious to other cats. Cats transfer the virus via bodily fluids so any sharing of bowls, grooming or sneezes will spread the virus. Cat herpes is viral and can’t be cured but there’s no reason to be afraid of a cat with herpes because a human can’t catch it.

What are the symptoms of cat herpes?

Cat herpes symptoms mimic having a cold. Cats may:

  • Sneeze
  • Have watery eyes
  • Squint
  • Look like or have conjunctivitis (pink eye)
  • Have goop (black crusty tears) in the corner of their eyes
  • Be super sleepy
  • Seem lethargic
  • Seem grumpy (especially Feri!)
  • Lack an appetite

How do you treat cat flu?

If they are comingViralys-L-Lysine-Powder up on a flare, I can tell when one of them starts squinting. It at that point that I pull out the Lysine and give them a dose or 2 mixed in with their food. This is the best way to treat a flare up since there is no cure.

Lysine is an amino acid and blocks the herpes virus.  Lysine comes in many different varieties of dispensing.  I’ve only used the Viralys brand as that is what I initially got from the vet.  However, the vet told me to check around because she knew they were more expensive so I compared prices on eBay and Amazon.  I buy mine on both eBay and Amazon and have never had a problem with the product.  It is definitely much cheaper than getting from the vet!

I have tried all the types of Viralys that are made.  You can check out my review of Viralys L-Lysine products here.  Let me know what you think!  Cheers!


  1. This is the first time I have ever heard of feline herpes. I have 2 cats and fortunately, neither of them have ever even gotten sick (knock on wood). How can you tell if your cat has herpes? I’m just curious. When I think of herpes, I think of a sore or blister on the lips. But this sounds more like a cold or flu?

    1. Yes, it is definetely more like the flu. They start to sneeze, get watery eyes and congestion. They handle it pretty well once they get over the first round. I just have to make sure I give them the Lysine when they start to flare as the congestion can turn in to an upper respitory infection.

  2. Hi Cat… From your comment it seems that the cats can get ill the 2nd time because of the feline herpes. Is there anything I can do to boost up their immune system since this disease is viral? And if they contracted the virus further on after the 1st time, will the seriousness of the symptoms still remain the same? By the way, awesome page you had written, so informative… thank you.

    1. Hi Kiev! Yes, cats can get ill more than once becasue once they get it, the virus stays in their system. A good way to keep on top of the disease is to give them a L-Lysine supplement to protect them from getting ill again. I’ve written a review about Viralys L-Lysine that you should check out. You can find it here.

      Generally, after the first timethe cat gets sick, the symptoms are much less severe and are well tolerated by the cat. At least mine! LOL

      Thank you for the kind words about my page. It is very mcuh appreciated! Cheers!

  3. Hey Cat! Thank you so much for the article!! My cat was diagnosed when we first got her with feline herpes 2 years ago but hasn’t had a flare up until now. I can tell she’s flaring up because only one eye seems to have the conjunctivitis & she’s been pretty lethargic & sleepy. 🙁 I’m so glad I came across this because I never heard of the l lysine. How often/ per day do you dose them with the l lysine? Again, thank you so much!!

    1. Awwww, poor baby! I hate to see them flaring because they look so miserable. Especially at the onset of the disease. As they get older and have the disease for longer, you will notice that they don’t flare as much. Mine only flare now when they are super traumatized (which is usually never!)

      When my kitties are flaring, I will usually dose them 3 times a day. I feed small feedings 3 times a day but if you’re only feeding twice a day then you can grab some treats for the third dose. Here is a link to the ones I use, my guys really like them. After the flare has subsided, I continue to dose for a week or so just to make sure that all the symptoms are gone but I knock it down to just twice a day.

      I hope your kitty feels better soon! Let me know if you have any further questions. Cheers!

  4. Hi! Our rescue cat passed the virus along to our one year old cat. It has probably been about 10 days since his eyes started getting goopy. We did drops and his eyes seem to be improving. Now he just sleeps soooo much and seems so sad. How long does this usually last? I feel so bad for him!

    1. Hi Erin, I know how you feel! Gyula was the last to get the virus and it hit him harder than the others. I remember feeling so bad for him and now I feel for your little guy too! It is really awful to see them like this. The drops for his eyes won’t really clear up conjunctivitis because it’s viral and not bacterial. It may help to soothe his eyes but that should clear up on its own in about 2 weeks so it sounds like his pink eye will be gone soon. As for the herpes flare, the first is ALWAYS the worst. It took Gyula about 3 and a half weeks to come out of it, the others were about 2 weeks. Gyula looked so sad too. It’s heartbreaking! He’s halfway there so just make sure you let him sleep the days away but also talk to him and gently pet him. It is depressing to them and they need emotional support. I hope he feels better soon!

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