Cat Diseases: Common Illnesses and What to Watch For
Your cat seemed fine yesterday, but today she’s not eating, hiding under the bed, and her third eyelid is showing. As a cat owner, recognizing the signs of cat diseases early can make a real difference in how quickly your vet can help. The problem is that cats are experts at masking how they feel.
Understanding common cat illnesses gives you a baseline so changes stand out. Whether you’re dealing with a bout of cat illness that clears in a day or noticing cat illnesses and symptoms that keep coming back, knowing what to look for helps you act faster. Cat disease symptoms range from obvious to subtle, and some of the most serious conditions give little warning.
Upper Respiratory and Immune-Related Conditions
Feline Herpesvirus and Calicivirus
These two viruses cause most feline upper respiratory infections. Symptoms include sneezing, runny nose, eye discharge, and reduced appetite. Most cats recover with supportive care, though herpesvirus can recur during stress. Vaccination helps reduce severity.
Feline Immunodeficiency Virus (FIV)
FIV weakens the immune system over time, making cats susceptible to secondary infections. Many FIV-positive cats live normal lives for years with routine veterinary monitoring. It spreads primarily through deep bite wounds between cats.
Feline Leukemia Virus (FeLV)
FeLV suppresses immunity and can cause anemia, lymphoma, and other serious conditions. Outdoor cats and those living with infected cats are at higher risk. A simple blood test at any vet visit can screen for it.
Digestive and Organ-Related Illnesses
Chronic Kidney Disease
One of the most common cat diseases in senior cats, kidney disease develops slowly. Watch for increased thirst, more frequent urination, weight loss, and decreased appetite. Bloodwork at annual vet visits catches it earlier, when management options are more effective.
Hyperthyroidism
An overactive thyroid gland is very common in cats over 10. Signs include weight loss despite a good appetite, increased vocalization, restlessness, and a racing heart. It’s manageable with medication, a prescription diet, or radioactive iodine therapy.
Inflammatory Bowel Disease (IBD)
Chronic vomiting and diarrhea with weight loss often point to IBD. A cat with this condition may cycle through good and bad stretches. Diagnosis usually requires bloodwork, imaging, and sometimes biopsy. Diet changes and medication help many cats significantly.
Dental and Skin Conditions
Periodontal disease affects the majority of cats over three years old and is a genuine health concern, not just a cosmetic one. Bacteria from infected gums can enter the bloodstream and affect the heart, kidneys, and liver. Bad breath, dropping food, and pawing at the mouth are warning signs.
Skin-related cat illness includes ringworm (a fungal infection, not a worm), allergic dermatitis, and parasitic infestations like fleas and mites. Hair loss, excessive scratching, and skin crusting all warrant a vet look.
Bottom Line
Most cat diseases are manageable when caught early, and your vet is your best partner in that effort. Annual wellness exams with bloodwork give you a snapshot of your cat’s internal health even when outward signs are absent. When something feels off, trust your instincts and make the call.
