Litter Box Changes (Urinating or Defecating Outside the Box)
If your cat has always been good about using the litter box but suddenly you’re finding puddles or piles elsewhere, pay attention. Frequent trips to the litter box or straining without producing much can indicate a urinary tract infection or blockage​. Urinating outside the box could be a sign of bladder irritation, kidney issues, or diabetes. Similarly, a cat that becomes constipated (straining in the box with little result) or has diarrhea may be sick. Never assume a potty accident is “spite”– it’s often a cry for help. Inappropriate elimination is one of the top signs something is medically or behaviorally wrong. For example, a cat with a painful urinary blockage or cystitis might associate the litter box with pain and avoid it. A cat with diarrhea from intestinal illness might not make it to the box in time. Bottom line: Sudden litter box avoidance or any straining/yowling during elimination is a big warning sign. Schedule a vet visit to rule out urinary tract disease, gastrointestinal problems, or even stress-related issues.
Changes in Appetite or Weight
A sick cat often has a change in appetite. Both loss of appetite and increased appetite can signal illness. If your cat who normally loves their food is now picking at it or refusing meals, something is wrong. Dental pain, kidney disease, gastrointestinal issues, or many other illnesses can reduce appetite. On the flip side, certain conditions like hyperthyroidism can make cats ravenous while they still lose weight​. Unexplained weight loss (especially if the cat is eating normally) is a serious red flag that should never be ignored​. Gradual weight loss may go unnoticed until it’s significant – regularly feel your cat’s body condition: if the backbone or ribs are becoming prominent, or the cat feels lighter, that’s important. Likewise, rapid weight gain or bloating could indicate problems like fluid accumulation. Tip: Weigh your cat periodically at home (you can use a baby scale or weigh yourself holding the cat vs. not holding) to catch changes early. Any sustained loss of appetite beyond 24 hours in a cat merits a vet exam – cats can develop hepatic lipidosis (fatty liver) if they stop eating for several days, compounding the problem. And if your cat is eating plenty but losing weight, conditions like diabetes or hyperthyroidism may be at play​. Essentially, any appetite or weight change should prompt investigation.
Increased Thirst and Urination
If you’re noticing you need to refill the water bowl far more often, or the litter box is soaking up a lot more urine clumps than before, your cat could be ill. Increased thirst (polydipsia) and urination (polyuria) are classic signs of several diseases, notably diabetes, chronic kidney disease, and hyperthyroidism​. Many healthy cats are fairly stealthy drinkers, so a sudden observable thirst is significant. You might see your cat hanging out by the water dish, or even seeking water from unusual places (sinks, cups). Check the litter – are the clumps larger or more numerous? This symptom combo should never be ignored. Diabetes mellitus, for example, causes high blood glucose that leads to excessive urination, and the cat drinks more to compensate​. Kidney disease impairs the kidney’s concentrating ability, so the cat urinates large volumes of dilute urine and becomes chronically thirsty. In older cats, these are often the first signs of illness owners notice. What to do: Don’t just keep topping off water – schedule a vet visit and bring a urine sample if possible. The vet will likely do bloodwork and urinalysis to check for these conditions. Catching them early makes them much more manageable. (Note: increased urine with normal thirst can also happen with a cat on certain medications or eating a high-salt diet; but it’s best to rule out medical issues).
Lethargy and Hiding
Every cat has lazy days, but a cat that is sick often shows lethargy – low energy, sleeping more than usual, not engaging in normal routines. Did your outgoing kitty suddenly start hiding under the bed all day? That withdrawal can signal pain or illness. Cats that feel unwell often seek out quiet, dark hiding spots. If your cat is normally social and suddenly you rarely see them, something is likely wrong. Lower energy levels are hard to gauge, but you know your cat’s normal. If playtime enthusiasm wanes or they don’t come to greet you as usual, pay attention. With fever or malaise, cats will curl up and sleep a lot. They might sit in a hunched position, eyes half-closed (the “sick cat loaf”). Note: Some cats hide when stressed by changes at home too, but if nothing changed in the environment, suspect health issues. Additionally, increased clinginess in a normally independent cat can also be a sign – some sick cats become very attached to their humans when they don’t feel well, almost asking for help. Essentially, any significant change in sociability – whether hiding or clingy – coupled with lethargy can indicate illness. This is a broad warning sign, so look for other clues (is the appetite off? grooming less?). When in doubt, a check-up is wise – your vet may find a fever or other issue on exam explaining the lethargy.
Changes in Grooming and Coat Condition
Cats are usually fastidious groomers. If you notice your cat’s coat is looking unkempt, greasy, or has dandruff, and the cat isn’t grooming like before, it could be due to illness. Pain or obesity can make grooming difficult. Arthritis in older cats, for example, often leads to less grooming (because it hurts to twist around) – you might see mats forming on a senior cat’s back or belly. Dental pain or mouth disease can also cause a cat to stop grooming (tongue or jaw movement might hurt). Conversely, over-grooming one area can signal a problem too – cats will lick excessively at a body part that’s bothering them (for instance, over-grooming the belly could indicate bladder pain; licking a limb could indicate joint pain or a skin irritation). Vomiting hairballs more than usual might be a clue your cat is over-grooming due to stress or skin issues. Essentially, any deviation in grooming habits is a hint: a normally sleek cat looking scruffy or a normal cat suddenly licking bald spots are both abnormal. If your cat has stopped grooming and looks messy, it often means they’re not well​. Inspect the skin and coat for fleas or irritation too. Over-grooming can create reddened areas or even sores. Bring up coat changes at the vet – it can help diagnose issues like arthritis (cat can’t reach back to groom) or metabolic diseases. You might need to assist with brushing or seek treatment for the underlying cause to restore your cat’s coat health.
Respiratory Symptoms (Sneezing, Coughing, Runny Eyes/Nose)
Sneezing once in a while isn’t alarming (cats do get dust up their nose!), but frequent sneezing, nasal discharge, or coughing are signs of illness. Sneezing with snot or runny eyes likely means an upper respiratory infection (like feline herpesvirus or calicivirus – the “cat flu”). If the discharge is clear and the cat is active and eating, it’s usually a mild infection. But if discharge becomes yellow/green and the cat is dull or not eating, the infection may be more serious or secondary bacterial. Coughing or wheezing can indicate lower airway disease like asthma – cats can develop bronchitis/asthma and may have episodic coughing (sometimes mistaken for hairball gagging). Any persistent cough or any difficulty breathing (open-mouth breathing or fast, labored breaths) is a huge warning sign – this can be an emergency (could be asthma attack, heart failure, fluid around lungs, etc.). Runny eyes could be conjunctivitis from a virus, or even something like a scratch on the eye. If your cat has any trouble breathing, seeks vet care immediately. A cat in respiratory distress may sit with neck extended and breathe through the mouth – that’s a crisis. Milder respiratory signs (sneezes and sniffles) should still be monitored – if they last more than a few days or worsen, see the vet. Cats do not get “common colds” as frequently as humans, so respiratory symptoms are usually due to specific infections or conditions. The key is how the cat is acting: a sniffling but playful cat that’s eating is usually okay to monitor. A sniffling cat that is hiding and not eating is sick and needs help. When in doubt, let a vet have a listen to your cat’s lungs and check those peepers.
Vomiting or Diarrhea
Occasional hairballs or the rare isolated vomit might not be cause for alarm (cats do like to yak up grass or the odd hairball). But repeated vomiting – more than once in a day, or a pattern of vomiting over days – is a warning sign. Frequent vomiting can indicate anything from dietary intolerances to hyperthyroidism, kidney disease, or gastrointestinal obstruction. Take note of what the vomit contains (food? hair? bile?) and when it occurs (right after eating? hours later?). Diarrhea or very loose stool that persists is also a sign of trouble – parasites, dietary issues, or intestinal diseases could be to blame. If you see any blood in vomit or stool, or the cat is vomiting repeatedly and can’t even hold down water, seek veterinary care promptly. Chronic vomiting (even if not severe each time) is not “normal” for a cat – it warrants investigation, as it could be a sign of diseases like inflammatory bowel disease or even certain cancers. Don’t ignore litter box changes: diarrhea can quickly lead to dehydration in a cat, and it’s uncomfortable. When to worry: one vomit = watchful waiting; vomit more than twice or with other symptoms (lethargy, no appetite, etc.) = vet visit. Same for diarrhea lasting more than a day or containing blood. These symptoms can cause cats to feel awful and they often stop eating when GI upset is significant – leading to a cascade of new problems. So, nip it in the bud and get treatment (fluids, medications, diet change) as needed.
Pain or Sensitivity
Cats in pain can show some subtle signs: aggression or irritability when touched, hiding, decreased jumping or activity, and sometimes meowing or yelping if the painful area is contacted. Limping or difficulty going up/down stairs is an obvious sign of pain (in limbs or back). But some signs are as small as a flinch or growl when you pet a certain spot. Don’t assume a cat growling when picked up is “grumpy” – maybe it hurts their abdomen or spine. Dental pain might show up as a cat backing away from hard food or dropping kibble from the mouth. Eye pain can show as squinting one eye or pawing at it. Overall, any new sensitivity or change in how your cat tolerates handling could indicate pain. Check for injuries if something acute happened (a fall, a fight). For chronic pain like arthritis, you might notice your cat no longer jumps on counters or struggles to groom the base of their tail. Weight loss can accompany chronic pain as well (pain can stress them and reduce appetite). If you suspect pain, don’t wait – cats rarely “get better” on their own from painful conditions without help. A vet can diagnose the source and provide pain relief (there are cat-safe pain medications, never give human meds). Untreated pain not only causes suffering but can lead to secondary problems (a cat in pain might stop eating or start eliminating outside box, etc.). So it’s both a warning sign and something to address. Never ignore a hissing or swatting cat – ask why they are behaving that way; it could be their way of saying “I hurt.”
“Something’s Just Off” – Trust Your Gut
As a cat parent, you know your cat’s normal routines and personality. Sometimes the earliest sign of sickness is just a feeling that something is off. Perhaps your cat is normally waiting at the door when you get home, and lately they haven’t been. Or maybe they usually race to the food bowl in the morning, but today they didn’t. These small deviations can be the first clues. Cat owners often report they “just knew” their cat wasn’t feeling well even before concrete symptoms appeared. Trust your instincts. If your cat seems more aloof, or more needy, or is vocalizing more or less than usual, take note. A normally quiet cat that’s yowling could be in distress or pain; a usually chatty cat that’s suddenly silent might be too weak to protest. Monitor the litter box, food intake, water intake, and activity level – these are the big four indicators of health. Any sudden change in one of those – for example, a cat who usually finishes their 1/2 cup of kibble a day now only eating a few bites – is a loud warning bell (even though it’s one we might miss if not looking closely). Write down what you observe and call your vet to discuss whether it warrants an appointment. Vets appreciate when owners notice subtle changes; it can lead to early diagnosis of diseases. Remember, cats have evolved to hide signs of illness and pain​, so by the time clear signs appear, the cat may have been unwell for some time. Early intervention can save your cat’s life or at least make treatment easier. So never feel silly for bringing your cat in “just in case” – catching issues early is part of being a great cat guardian.
Takeaway: Know the common warning signs – changes in litter box habits, appetite/weight shifts, increased thirst, lethargy or hiding, poor grooming, respiratory or GI upsets, signs of pain – and act on them. It’s always better to have the vet say “false alarm, your cat is fine” than to miss a brewing illness. As the saying goes, “An ounce of prevention is worth a pound of cure.” By paying attention to your cat’s daily patterns and never ignoring these warning signs, you’ll help ensure your feline friend stays as healthy and happy as possible. After all, you are your cat’s first line of healthcare – and they rely on you to notice when they need help.
Sources:Â
Veterinary guidelines on signs of illness​ vcahospitals.com
Common symptoms linked to diseases​ amcny.org
​AVMA data on longer lives for spayed/neutered cats (for context of health monitoring)​ avma.org
