Cat Flu: Signs, Home Care and Where L-Lysine Fits
Sneezing, a runny nose, watery eyes and a sudden loss of appetite — cat flu is one of the most common health issues in cats, especially kittens and multi-cat homes. This guide explains the causes, the warning signs that need a vet, and what you can do at home.
See a vet promptly if your cat hasn’t eaten for more than 24 hours, is struggling to breathe or breathing through the mouth, is very lethargic, has badly swollen eyes, or is a young kitten. Never give human medicine — paracetamol, for example, is highly toxic to cats.
What is cat flu?
“Cat flu” is the everyday name for an upper respiratory infection. Most cases are caused by two viruses: feline herpesvirus (FHV-1) and feline calicivirus (FCV), sometimes with a bacterial infection on top. It spreads easily between cats through sneeze droplets, shared bowls and human hands.
Common signs
- Sneezing and nasal discharge
- Watery, sticky or red eyes
- Fever and low energy
- Loss of appetite — a blocked nose makes it hard for cats to smell food
- Mouth or tongue ulcers (more typical of calicivirus)
Most mild cases recover in roughly 1 to 3 weeks with good care, but kittens and senior cats can go downhill quickly.
Why cat flu can come back
Feline herpesvirus can stay dormant in a cat’s body after the first infection. Stress — moving house, a new pet, illness — can reactivate it and bring the signs back. That is why lowering stress is part of good care.
Vaccination
Core cat vaccines (often called F3 or FVRCP) help protect against herpesvirus and calicivirus. They may not prevent infection completely, but usually make the signs milder. Ask your vet about the right schedule.
Home care
- Gently wipe the eyes and nose with clean, damp cotton
- Sit with your cat in a steamy bathroom for a few minutes to help loosen the nose
- Offer strong-smelling wet food, slightly warmed, to encourage eating
- Keep fresh water available at all times
- Separate a sick cat from others and wash your hands after handling
- Keep things calm: a quiet resting spot and a predictable routine
Where does L-Lysine fit?
L-Lysine is an amino acid that many cat owners use as daily support, especially for cats with a history of herpesvirus. Research on how well it works is mixed, so think of it as nutritional support within a daily routine — not a medicine, and not a replacement for vet treatment or vaccination. Follow the label or your vet’s advice on dosage.
Daily support during and after cat flu
Vet care, enough food and water, and a calm environment matter most.
Support your cat’s immune health daily
PROUDPET Supreme L-Lysine can be added to your cat’s daily routine to support normal immune function and overall wellbeing.
FAQ
What medicine is used for cat flu?
There is no single medicine for every case. Your vet may prescribe antibiotics for a secondary bacterial infection, eye drops or other treatment depending on the signs. Never give human medicine without vet advice — some are toxic to cats.
Can humans catch cat flu?
The common cat flu viruses (FHV-1 and FCV) do not infect humans, but they spread very easily between cats.
Is L-Lysine safe for kittens?
Follow the age guidance and dosage on the product label, and ask your vet if the kitten is very young or currently unwell.
How long does cat flu last?
Mild cases usually recover in about 1 to 3 weeks. If signs get worse or your cat stops eating, see a vet.