Cats are experts at hiding discomfort, so illness often shows up as a small change before it becomes an obvious crisis. A cat who suddenly drinks more, skips meals, urinates outside the litter box, or stops jumping onto a favourite chair may be giving you an early clue. This cat symptoms guide covers 12 common feline diseases and conditions, the signs owners commonly notice, and the situations that deserve urgent veterinary care.
Common cat illnesses and the symptoms to watch for
1. Feline lower urinary tract disease
Urinary problems can cause frequent litter-box trips, straining, crying while urinating, blood in the urine, genital licking, or urinating outside the box. People often search for cat UTI symptoms, but not every urinary episode is a bacterial infection; inflammation, bladder stones, and urethral blockage can cause similar signs. A cat, especially a male, who strains but produces little or no urine needs emergency veterinary care because a blockage can rapidly become life-threatening.
2. Chronic kidney disease
Chronic kidney disease is especially common in older cats and may be quiet early on. As kidney function declines, owners may notice increased thirst, larger urine clumps, weight loss, poor appetite, lethargy, vomiting, or an unkempt coat. Routine senior-cat bloodwork and urinalysis may reveal disease before symptoms become dramatic.
3. Hyperthyroidism
Hyperthyroidism in cats usually affects middle-aged and older animals. A classic pattern is weight loss despite a strong appetite. Increased thirst and urination, restlessness, vomiting, diarrhoea, a fast heart rate, and a greasy or poorly groomed coat can also occur. The signs overlap with diabetes and kidney disease, so diagnosis requires veterinary testing.
4. Diabetes mellitus
Diabetic cats commonly drink and urinate more, lose weight, and remain unusually hungry. Some become weak in the hind legs or walk with their hocks dropped closer to the floor. A single high glucose reading at the clinic does not always prove diabetes because stress can temporarily raise blood sugar, so vets may use repeat blood and urine testing or other laboratory markers.
5. Upper respiratory infection
Upper respiratory infections are common where cats live in close contact, including shelters and multi-cat homes. Sneezing, nasal or eye discharge, conjunctivitis, reduced appetite, lethargy, fever, and mouth ulcers may appear. Congestion can make food less appealing because cats rely heavily on smell. Laboured or open-mouth breathing needs prompt veterinary attention.
6. Dental disease
Gingivitis, periodontal disease, and tooth resorption can be extremely painful even when a cat still eats. Watch for bad breath, red or bleeding gums, drooling, pawing at the mouth, chewing on one side, dropping food, or preferring soft food. A cat that approaches the bowl eagerly but backs away after trying to bite may be showing oral pain rather than fussiness.
7. Feline asthma
Feline asthma may cause coughing, wheezing, rapid breathing, or increased breathing effort. During an attack, a cat may crouch low and stretch its neck forward. Owners sometimes mistake coughing for an attempt to bring up a hairball, especially when nothing appears. Open-mouth breathing or obvious respiratory distress is an emergency.
8. Pancreatitis
Pancreatitis can be difficult to recognise because cats often show vague signs. Reduced appetite and lethargy are common, while vomiting, weight loss, dehydration, diarrhoea, or abdominal discomfort may also occur. A normally enthusiastic eater who suddenly refuses food deserves veterinary advice, particularly if the cat is also hiding, weak, or vomiting.
9. Ringworm
Despite the name, ringworm is a fungal skin infection rather than a worm. Signs may include patches of hair loss, broken hairs, scaly or crusty skin, dandruff, itching, or inflamed areas. It can spread between animals and people, so suspected cases should be assessed and managed carefully rather than treated as simple dry skin.
10. Gastrointestinal parasites
Roundworms, hookworms, tapeworms, and other intestinal parasites are particularly important in kittens and cats that hunt or go outdoors. Some cats show no symptoms, but diarrhoea, vomiting, a pot-bellied appearance, poor growth, weight loss, pale gums, or a dull coat can occur. Veterinary-recommended parasite prevention and faecal testing can identify problems that are not visible to the naked eye.
11. Osteoarthritis
Arthritis in cats often looks less like obvious limping and more like a change in routine. Affected cats may hesitate before jumping, avoid stairs, struggle with high-sided litter boxes, sleep more, groom less, or become irritable when handled. If an older cat starts toileting beside the litter box, pain getting into it may be part of the problem.
12. Flea allergy dermatitis
Some cats react strongly to flea saliva, so even a few bites can cause intense itching. Repeated scratching, overgrooming, hair loss, and red or crusty bumps commonly affect the lower back, thighs, abdomen, head, or neck. Fleas can be hard to spot because cats groom them away, so veterinary guidance on cat-safe flea control is often more useful than a quick coat check.
When symptoms need urgent veterinary care
Seek urgent veterinary help for difficulty breathing, open-mouth breathing, collapse, seizures, repeated vomiting with weakness, severe bleeding, suspected poisoning, or inability to pass urine. A practical rule is to focus on function: if your cat cannot breathe comfortably, urinate, stand normally, or keep food and water down, the situation may be urgent.
Related internal topics that naturally complement this guide include cat vaccination schedules, caring for a senior cat, and preparing for a veterinary check-up.
Frequently asked questions
What are the first signs that a cat may be ill?
Early clues include changes in appetite, thirst, litter-box habits, grooming, sleep, activity, body weight, or social behaviour. Because cats hide illness well, a change from your cat’s normal pattern matters more than any single universal symptom.
Can I diagnose a cat illness from symptoms at home?
No. Many conditions share the same signs. Weight loss and increased thirst, for example, can occur with kidney disease, diabetes, or hyperthyroidism. A veterinarian may need an examination, blood tests, urinalysis, imaging, or other tests to identify the cause.
How long should I wait if my cat stops eating?
A sudden loss of appetite should be taken seriously. Contact a veterinarian promptly if your cat refuses food, especially if the change lasts into the next day or is accompanied by vomiting, weakness, pain, breathing changes, or other symptoms.
Are urinary symptoms always caused by a UTI?
No. Cats can strain, urinate frequently, or pass blood because of bladder inflammation, stones, infection, or urethral obstruction. Since the symptoms overlap, testing is important. A cat producing little or no urine while straining needs emergency care.
Recognising patterns can lead to earlier care
The most useful skill for a cat owner is knowing what is normal for that individual cat. Small shifts in weight, appetite, thirst, mobility, grooming, or litter-box habits can help uncover common cat illnesses and their symptoms earlier. Keep notes when something changes, take a short video if an unusual cough or movement is intermittent, and bring those observations to your vet. Early attention gives your cat a better chance of getting the right assessment before a subtle problem becomes serious.