Cats are really good at hiding signs of illness but here are some things to watch out for: Dull fur. Strange bumps. Loss of appetite. Diarrhea for more than one day. Trouble urinating or defecating. Urinating or defecating outside of litter box. Cuts. Blood in the urine or feces. Scabs. Coughing, wheezing or excessive sneezing. Unusual discharge from the eyes and nose. Sudden weight change. Drooling. Swelling. Hair loss. Sluggishness. Sudden aggressive or passive behavior change.