Anyone who lives with a cat knows that, over time, you learn to recognize when something is wrong. Even so, felines are true experts at hide the pain and discomfortSo it's not always easy to detect that they're sick until the problem is already advanced. That's why it's so important to know the most common warning signs and not ignore small, everyday changes.
In this guide you will find a detailed explanation of the main symptoms of illness in catsThe guide covers various aspects of feline health, including behavior, appetite, sleep, hygiene, digestion, urination, respiration, skin, eyes, ears, and more. We'll also review common feline diseases, what to do if you suspect your cat is sick, and when it's urgent to see a veterinarian. The goal is to provide you with a clear reference to react promptly, but this guide should never replace professional veterinary advice.
1. Changes in behavior: the first clue that something is wrong
One of the earliest indicators of illness in a feline is the sudden changes in their usual behaviorCats are creatures of habit, so any marked variation in their behavior or activity level deserves attention.
A normally sociable cat can suddenly become more sullen, irritable, or aggressiveThey may avoid being petted or hide in places they didn't previously seek refuge. Conversely, a normally calm cat might suddenly start meowing incessantly, follow you around the house, or appear very restless, especially at night, which could be related to pain, stress, or metabolic disorders.
La excessive vocalization This is another common sign. A previously silent cat that suddenly starts meowing constantly, or that emits different meows (deeper, longer, or plaintive), may be indicating that something hurts, that it feels anxious, or that it's experiencing some internal change that we don't immediately understand.
It is also worrying when the cat shows apathy or indifference He does things he used to love: he stops playing with his favorite toys, he no longer explores, he doesn't come when you call him, or he seems absent even when there are interesting stimuli around him.
Finally, sudden aggression, biting when touched in certain areas of the body, or exaggerated reactions when handled can be signs of localized pain or physical discomfortIn these cases, in addition to checking at home for obvious injuries, it is essential to make an appointment at the veterinary clinic.
2. Changes in activity and sleep
Although cats sleep many hours (between 12 and 16 a day), a clear change in their usual schedule can indicate a problem. A cat that suddenly spends a large part of the day sleeping. sleeping more deeplyA child who does not react to noises that used to wake them up, or who does not get up even to eat, may be ill.
Lethargy, a lack of desire to move, or staying in a corner without interacting are typical signs of pain, fever, anemia, or systemic diseases such as kidney or heart problems. They can also mask infectious or inflammatory processes that cause general malaise.
At the opposite extreme, a cat that begins to show itself hyperactive, restless, or unable to rest at night You could be experiencing internal discomfort, intense itching, environmental stress, or even hormonal disorders, such as hyperthyroidism, which increases activity and nervousness.
Observing whether the cat changes its usual resting place is also helpful. Constantly seeking out cold or well-hidden areas can be indicative of [something]. pain, fever, or fearIf these changes last more than one or two days, it is best to consult a doctor.
3. Changes in appetite, thirst, and weight
Any noticeable change in the amount of food or water the cat ingests It can be a symptom of illness. Cats should not go more than 24 hours without eating: longer periods of fasting can trigger hepatic lipidosis, a serious condition in which the liver becomes overloaded with fat.
La loss of appetite (Not approaching the food bowl, sniffing the food and walking away, eating significantly less without explanation) can be related to dental problems, mouth pain, nausea, gastrointestinal issues, kidney problems, systemic infections, or even tumors. If vomiting, diarrhea, or lethargy are also present, a visit to the veterinarian should be immediate.
Conversely, a sudden increase in appetite (polyphagia) may indicate hyperthyroidism, diabetes, or other hormonal imbalancesIn these cases, it is common for the cat to eat more than normal, but still lose weight, or to be especially irritable and active.
Excessive thirst (polydipsia) and increased urination are key signs of chronic kidney failure and diabetes mellitusTwo relatively common diseases in middle-aged and older cats. Offer wet cat food This can help maintain hydration. Noticing that the water bowl is emptying much faster or that the litter box is soaked is a clear reason for blood work.
We must also monitor the weight loss or gain without an apparent reasonProgressive weight loss, even while eating the same amount, can be linked to kidney disease, tumors, chronic infections, IVF, FeLV, or intestinal absorption problems. Weight gain, on the other hand, contributes to obesity and all its consequences: difficulty breathing, joint problems, a sedentary lifestyle, increased risk of diabetes, and a reduced quality of life.
4. Digestive signs: vomiting, diarrhea, and other gastrointestinal problems
Cats can vomit occasionally without it being a serious problem, for example when expelling hair ballsHowever, when vomiting is repeated several times, lasts for more than 24 hours, contains traces of blood, or the animal is lethargic, it is a clear sign of illness.
The repeated vomiting They may be due to obstructions in the esophagus, stomach or intestine (by foreign bodies, very compact hairballs, tumors), gastritis, kidney disease, pancreatitis, poisonings (from foods forbidden for cats)Viral infections (such as feline panleukopenia) or metabolic disorders can also cause this condition. In any of these cases, a veterinary evaluation is mandatory.
Persistent diarrhea, very loose stools, or, on the contrary, very dry and difficult to expelThese are another gastrointestinal indicator. Sudden changes in stool consistency, the presence of mucus, visible parasites, black or bloody stools require further investigation, as they may be associated with infections, parasites, food intolerances, inflammatory bowel disease, or more serious problems.
In the case of feline panleukopenia (also known as feline distemper), a serious and potentially fatal viral disease, there is a combination of fever, severe vomiting, severe diarrhea, dehydration, and anorexiaIn such a situation, veterinary care is of the utmost urgency. Although supportive treatment exists, it is not always effective, making vaccination the best prevention.
Other digestive signs to watch out for include Bad breath of digestive originA distended or painful abdomen, straining during bowel movements, and pain upon palpation of the abdominal area are all signs of abdominal pain. Home self-examination can be helpful, but it should never replace tests such as ultrasounds, X-rays, or stool and blood tests, which allow for a more precise diagnosis.
5. Urinary problems and use of the litter box
Changes in urination habits are one of the most important signs of illness in cats. A cat that starts to urinate outside the litter boxA person who frequently goes to the toilet without results or who complains when urinating may be suffering from a urinary disorder.
Among the most common problems we find the feline cystitisUrinary tract infections, the presence of crystals or stones in the bladder, and feline lower urinary tract disease (FLUTD) can all cause severe pain, straining to urinate, blood in the urine, or very frequent and scanty urination.
In the case of males, there is a special risk: urethral obstructionWhen crystals, inflammatory plugs, or small stones block the urethra, the cat cannot urinate. This is an extreme veterinary emergency, as it can lead to severe electrolyte imbalances, kidney damage, and death within hours if left untreated.
Other concerning urinary signs include difficulty urinating, forced posture in the litter boxInsistent licking of the genital area and meowing in pain when trying to urinate are common signs. This shouldn't be confused with a simple "behavioral problem": often, urinating outside the litter box is the cat's way of showing that something is bothering them.
Additionally, blood in the urine, very dark urine, or urine with a much stronger odor than usual can be indicators of infection, inflammation, or stonesAny change of this type requires veterinary consultation and, in most cases, urinalysis and additional tests.
6. Coat and grooming as a reflection of their health
The appearance of a healthy cat's coat is often very revealing: shiny, clean, soft hair without bald patchesCats spend a good part of the day on their hygiene, so when something goes wrong with their grooming routine We need to ask ourselves why.
If a cat stops grooming itself, or does so much less frequently, its fur often becomes dull and brittle. dull, rough, knotty or dandruffThis may be related to pain (for example, arthritis in older cats, spinal discomfort, or being overweight that prevents them from turning properly), systemic diseases, fever, dehydration, or states of general weakness.
By contrast, a excessive and compulsive grooming Tickling in certain areas (belly, legs, base of tail, flanks) is often associated with itching, allergies, fleas, dermatitis, external parasites, or even anxiety and stress. This behavior can lead to bald patches, skin wounds, and excessive hair loss.
The presence of lots of dandruff It can be a sign of stress, poor diet, skin conditions, or, again, improper grooming. If dandruff is only noticed after a trip or a temporary episode of anxiety, it usually clears up on its own, but if it persists, it's worth investigating the cause.
Another important detail appears when the cat presents the The fur on the back is greasy and dirty, while the rest of the body is clean.This usually happens when the animal is obese and cannot physically reach that area, or when there is pain when bending, preventing it from grooming normally. This is especially common in cats with joint or spinal problems.
7. Ears, hearing and balance
Healthy ears have a characteristic appearance: the inside of pink color, clean and without excess waxand a normally upright and mobile posture. If you notice black spots, scabs, dark earwax, a bad odor, or if the cat is persistently scratching its head and neck, it may have ear infections, mites, or another infection.
Feline otitis can cause itching, pain, frequent head jerking, tilting of the neck to one side and even loss of balance or disorientation. In advanced stages, the cat may keep one ear drooping or be reluctant to have that area touched, even whining at the slightest contact.
In addition, some cats may have hearing problems. A typical sign of partial or total deafness It's that the cat meows a lot and very loudly (it can't hear itself), that it gets startled when you touch it from behind without seeing it coming, that it doesn't react to everyday sounds (doorbell, opening cans, footsteps) or that it doesn't come out to greet you when you arrive home because it simply doesn't hear you.
In any case, ear infections, balance problems, or suspected hearing loss should all be evaluated in a clinic. A thorough otoscopic examination, and if necessary, further testing, will determine the cause and treatment.
8. Nose, eyes and respiratory signs
A healthy cat's nose is usually slightly damp and coolA very dry, hot nose can indicate a fever, although it's not a reliable diagnostic method on its own; ideally, a rectal temperature should be taken with a specific thermometer. In cats, a temperature of around 39,4 °C (102 °F) or higher is considered a fever.
Regarding the eyes, some breeds commonly have black eye discharge without it being a problem; if you notice any changes, consult a doctor. cat eye health. However, the whitish, yellowish or greenish secretionsVery watery, swollen, or red eyes are symptoms of conjunctivitis or respiratory infections (such as feline herpesvirus or calicivirus).
A very alarming sign is the constant visibility of third eyelid (that whitish membrane that appears in the inner corner of the eye). When seen in a cat that is awake and active, it usually indicates pain, dehydration, fever, or systemic illness and requires immediate examination.
Respiratory problems manifest themselves with cough, frequent sneezing, runny nose, noisy or wheezing breathing, panting at rest, or difficulty breathingA cat that is breathing very fast, with its mouth slightly open, crouching down to try to fill its lungs, or appearing very restless while breathing, is in a potentially serious situation.
Viral respiratory infections, pneumonia, feline asthma, and some heart diseases can cause severe respiratory distressIn these cases, you shouldn't wait: it's a veterinary emergency, especially if it's combined with lethargy and lack of appetite.
9. Mouth, teeth and bad breath
The oral cavity is another area where multiple health problems are reflected. very bad breath (halitosis) is not normal and is usually associated with periodontal disease: tartar buildup, inflamed gums, gingivitis and, over time, infection of tooth roots.
Cats with mouth pain may eating more slowly, dropping food, preferring canned food to dry kibble, drooling excessively, or avoiding chewingSome even stop eating, which worsens the condition and can trigger other health problems. It's also common for them to rub their mouths with their paws or to avoid having their heads touched.
Systemic diseases such as chronic renal insufficiency They can also cause characteristic bad breath, as well as mouth ulcers and weight loss. Therefore, if you notice any changes in your breath, the appearance of your gums (red, bleeding, receding), or your eating habits, it's advisable to schedule a complete dental checkup.
Excessive and persistent drooling, along with a refusal to eat, may be related to oral ulcers, embedded foreign bodies, tumors, poisoning, or viral diseasesOnly a direct examination will allow the exact cause to be identified and the appropriate treatment to be established.
10. Common diseases in cats and their most typical symptoms
In addition to the general signs already discussed, it is useful to know some common feline diseases and the symptoms with which they usually manifest, in order to recognize them in time and seek professional help.
Obesity: It is one of the most common health problems in domestic cats. An obese animal moves with difficulty, tires quickly, and may have respiratory problems, lethargy, and lack of mobilityFurthermore, obesity increases the risk of diabetes, joint disease, and hepatic lipidosis. The solution lies in a strict, balanced diet, appropriate exercise, and veterinary monitoring.
Feline immunodeficiency virus (FIV): Known as the “HIV of cats,” it affects the immune system and makes them more susceptible to infections. Symptoms include swollen lymph nodes, weight loss, fever, hair loss, recurrent oral and eye infectionsAlthough it is not always directly fatal, it does reduce the cat's ability to fight other diseases.
Feline leukemia (FeLV): It is transmitted through bodily fluids (saliva, blood, etc.) and causes significant immunosuppression. Its signs can be highly varied: seizures, difficulty breathing, weight loss, frequent infections, and anemiaPreventive vaccines exist, and if infection is suspected, specific tests are essential.
Conjunctivitis: very common, especially in kittens, leads to reddish eyes, excessive eye discharge, swollen eyelids, and corneal opacitySome types of conjunctivitis are infectious, so it is advisable to quarantine affected cats to prevent contagion, in addition to following the treatment indicated by the veterinarian.
Otitis: inflammation or infection of the ear that may manifest as Intense itching, head shaking, discomfort when touching the area, wax buildup, and, in severe cases, hearing lossIt requires specific treatment, which may include professional cleaning, ear drops, and systemic medication.
Feline panleukopenia: A highly contagious and serious viral disease, similar to canine parvovirus. Affected cats exhibit High fever or hypothermia, vomiting, severe diarrhea, dehydration, and total loss of appetiteThey require intensive care and hospitalization in many cases, and even then the prognosis may be guarded.
Allergic diseases: Cats may react to pollen, perfumes, cleaning products, tobacco smoke, fleas, or certain foodsSymptoms include coughing, sneezing, runny nose or eyes, itchy nose and eyes, vomiting, or diarrhea. Identifying the allergen and adjusting the environment and diet is key to improving quality of life.
Chronic kidney failure: very common in older cats, it presents with Increased thirst and urination, loss of appetite, bad breath, vomiting, and weaknessIt is a progressive disease that requires early diagnosis through blood and urine tests, and a treatment plan to slow its progression.
Mellitus diabetes: characterized by Excessive thirst, frequent urination, increased appetite, and weight lossIt requires strict control, a proper diet and, in many cases, insulin treatment and regular check-ups.
11. Other physical signs that may indicate illness
Beyond the main symptoms, there are small details that also reveal the cat's state of health. The tail, for example, is usually active and in motion In a healthy cat, a tail is part of its balance and body language. A tail that is always down or that the cat doesn't move could suggest injury or pain.
Some cats show episodes of hypersensitivity in the backSymptoms include cramps, skin spasms, sudden running, rapid grooming, and aggressive scratching. Sometimes this is simply labeled "feline hyperesthesia," but it's important to rule out skin problems, ear issues, allergies, or genuine pain before resorting to anti-anxiety medication without investigating the underlying cause.
The cat's body is designed to jump, run, climb and make very precise movementsIf you notice that your partner avoids climbing places they used to climb effortlessly, misjudges jumps, trips easily, or moves stiffly, they may have joint, muscle, or neurological pain.
It's also important to occasionally feel your cat's body, including the abdomen and, in the case of female cats, the mammary area. Detecting any abnormalities will help you check your cat's body. lumps, cysts or bumps Any new appearance of a lump should take you to the vet as soon as possible, since early detection is key in many tumors and mammary problems.
Other general warning signs include jaundice (yellowish color in gums or skin), the seizures, persistent limping, tremors or chills and any sudden change in their appearance or behavior that you cannot explain.
12. What to do if you think your cat is sick?
When you detect any of the signs described, the first thing to do is Observe calmly and take notes What changes do you see: since when, how intense, whether they eat or drink, how they use the litter box, whether they vomit, whether there is diarrhea, etc. All this information will be essential for the veterinarian.
If the symptoms are mild and recent (for example, an isolated sneeze in a vaccinated cat, or a slightly more lethargic day but still eating), you can monitor your cat for 24 hours, provided it doesn't worsen. However, if there are loss of appetite for more than a day, difficulty breathing, inability to urinate, seizures, extreme apathy, or signs of severe painYou should go to the clinic immediately.
It's never a good idea self-medicating a cat with human drugs or other medications you have at home, since many products safe for people or dogs are toxic to cats. Always follow a professional's instructions, both regarding dosage and type of treatment.
Prevention remains the best tool: keeping your calendar up to date vaccination Deworming, providing a balanced diet, controlling weight, providing environmental enrichment to reduce stress, and attending regular check-ups, especially for older cats, are basic pillars for extending their life with good quality.
Ultimately, you know your cat best. When you notice something "off" in their behavior or movements, however small it may seem, there's usually a reason. Act quickly, seek professional advice, and don't dismiss the signs. signs of illness in cats It is the key for your partner to continue enjoying a long, peaceful and happy life by your side.
