FIP CLINICAL PATTERNS
Wet, dry, ocular and neurological FIP
FIP is a spectrum rather than two perfectly separate diseases. Understanding the pattern helps owners report changes, but classification and treatment decisions belong with a veterinarian.
Effusive and non-effusive patterns
Effusive—or ‘wet’—FIP is associated with fluid in the abdomen and/or chest. Non-effusive—or ‘dry’—FIP may involve inflammatory lesions in organs without obvious fluid. Mixed and changing presentations occur, so one label cannot replace a complete assessment.
Abdominal or chest fluid may predominate
Organ lesions may predominate without obvious fluid
Inflammation may affect internal eye structures
Gait, balance, behaviour or seizure signs may occur
Ocular FIP
Possible findings include uveitis, colour or clarity changes, unequal pupils and altered vision. These signs also occur with other diseases and require an ophthalmic examination.
A 2026 retrospective study reported ocular abnormalities in 48 of 118 cats diagnosed with FIP (40.7%). This was a referral population and should not be treated as the prevalence in all cats.
Neurological FIP
Ataxia, tremor, seizures, weakness, altered behaviour and cranial nerve abnormalities are among reported signs. Neurological disease changes diagnostic and monitoring considerations; online symptom matching is unsafe.
What to document for the appointment
- Videos of gait, tremor or unusual eye movement
- Daily weight, appetite, temperature and activity
- Breathing rate at rest and abdominal size
- Previous test results and a complete medication list
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