Prognosis for FIP varies depending on disease form and the individual cat. Some cases achieve remission or significant improvement with specialist antiviral treatment. Speak with your vet about your cat's specific prognosis and treatment options.

How can I tell if my cat has FIP?

Diagnosis typically requires a combination of clinical history, blood tests, imaging, and specific tests such as PCR or histopathology. A definitive diagnosis is made by a veterinarian — further workup at a clinic is recommended.

What can I observe at home to help the vet?

You can help by recording daily weight, temperature, appetite, and toileting changes at home. Note when symptoms started, and bring photos or video clips — this information helps your vet build an accurate picture of the illness quickly.

What records should I bring to the vet appointment?

Bring a timeline of when symptoms started and how they have changed, your daily weight and temperature log, any previous test results or reports, and a list of current medications, supplements, and vaccines. This helps your vet assess the case more efficiently.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Feline Infectious Peritonitis (FIP) in Cats: Symptoms, Diagnosis & Treatment Guide [2025]

Feline infectious peritonitis (FIP) is a life-threatening disease caused by a mutated feline coronavirus. It presents in two forms — wet (effusive) and dry (non-effusive). New antiviral therapies (GS-441524) have significantly improved remission rates.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ISFM, ACVIM, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Sudden complete weakness in the hind limbs — unable to stand or move independently
•Persistent high fever lasting multiple days accompanied by extreme lethargy and unresponsiveness
•Severe seizures or altered consciousness with markedly reduced response to surroundings

Schedule a Clinic Visit Soon (within 24–72 hours)

•Noticeable weight loss over a short period with persistently reduced appetite
•Recurrent or unstable fever that returns after subsiding
•Changes in behavior or gait — unsteady walking or poor coordination

01What symptoms suggest something is wrong?

FIP can present in many ways and may deteriorate rapidly. Common signs include systemic illness alongside neurological or ocular abnormalities — monitor closely for sudden changes.

Rapid and noticeable weight loss over a short period
Recurring or persistent fever that is difficult to bring down
Seizures, collapse, or other changes in neurological behaviour
Unsteady gait, stumbling, or loss of coordination
Jaundice — yellowing of the eyes, skin, or mucous membranes

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden hindlimb paralysis or complete inability to move or stand
⚠️ High fever with severe lethargy or prolonged unresponsiveness
⚠️ Continuous seizures or a marked change in consciousness or responsiveness

02How can you assess the situation at home? Key observations and when to go to emergency

Systematic home monitoring can speed up diagnosis: weigh and take temperature daily, log appetite and toileting changes, and keep photo or video records of abnormal movement or behaviour.

Weigh your cat at a fixed time each day and track the trend
Take your cat's temperature regularly and note the time and reading
Record changes in appetite, food intake, and vomiting frequency
Watch for abnormal urine or stool colour and changes in toileting habits
Observe for any decline in alertness, activity level, or willingness to play
Photograph or video any abnormalities and schedule a vet visit promptly

03How will the vet make a diagnosis? Common diagnostic tests

Your vet will start with a physical examination and build toward a diagnosis using blood work, imaging, and targeted tests to determine whether FIP or another condition is present.

Full physical examination, including basic neurological and ophthalmic assessment

Blood tests (complete blood count and biochemistry panel) to evaluate organ function

Specialised testing such as PCR or viral nucleic acid assays

Tissue biopsy or histopathology for definitive diagnosis when indicated

Imaging studies (ultrasound, X-ray, or advanced CT) to assess chest and abdominal changes

Consider referral to a specialist hospital capable of PCR testing and pathology

04What happens after diagnosis? Medications, dietary adjustments, and home care

FIP management follows your vet's guidance and requires close monitoring — ongoing recheck examinations are as important as the treatment itself for tracking efficacy and side effects.

Follow the prescribed treatment plan and attend all scheduled recheck appointments
Undergo regular blood and imaging follow-ups to monitor treatment response
Continue tracking weight, appetite, and alertness at home between visits
Report any suspected medication side effects to the veterinary team promptly
Contact your vet immediately if symptoms change suddenly or worsen

05What should you prepare before the vet visit? Key information to help your vet work efficiently

Write down when symptoms first appeared and how they have progressed

Bring a daily log of weight, temperature, and appetite readings

Bring photos or videos of abnormal behaviour or gait

Prepare a list of current medications, supplements, and vaccination history

Bring any previous test results or imaging from other clinics

Call ahead to book an appointment and mention that PCR or advanced testing may be needed

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Incoordination

Decreased activity

Elevated temperature

Yellow skin/eyes

Loss of appetite

Abnormal growth