Can cat colds clear up on their own? Seek immediate veterinary care if these symptoms appear!

Cat flu, more accurately known in medical terms as an “upper respiratory tract infection”, is a common illness affecting cats worldwide. It not only causes obvious discomfort to cats, but if not managed properly, it may also lead to serious complications and even become life-threatening. This article will examine in detail the causes, symptoms, treatment options and prevention strategies for cat flu, and explore how pet insurance can help ensure pets receive appropriate treatment when they are unwell, providing pet owners with a comprehensive care guide. 

Cat flu is not a single disease, but a general term for a range of infectious conditions that affect a cat’s upper respiratory system. This group of symptoms mainly affects the nose, throat and eyes. The vast majority of cases (around 90%) are caused by viruses, and studies indicate that the most common culprits are feline herpesvirus (FHV-1) and feline calicivirus (FCV). In addition, bacterial infections (such as chlamydia and Bordetella) may occur on their own or alongside a viral infection, making the condition more complex.  

These infections are highly contagious. Viruses or bacteria can spread through the saliva, eye and nasal secretions of infected cats, either by direct contact or via droplets. Shared food bowls, water bowls, toys and even owners’ hands can become transmission routes. Outbreaks can spread particularly quickly in high-density environments such as multi-cat households or shelters.  

Causes of Cat Flu and High-Risk Groups

Viral infection is the core cause of cat flu. Feline herpesvirus (FHV-1) is not only highly contagious, but once a cat is infected, the virus remains dormant for life in the cat’s nervous system. When a cat is under stress (such as changes in the environment or the introduction of a new family member) or its immunity is weakened, the virus may reactivate and trigger a recurrence of symptoms. Feline calicivirus (FCV), meanwhile, is known for its varied clinical signs. In addition to typical respiratory symptoms, it may also cause oral ulcers, leading cats to refuse food because of pain.  

Although cats of any age can be infected, certain groups are at higher risk and may develop more severe illness. Research indicates that these high-risk groups include kittens and older cats, cats with weaker immunity, cats in multi-cat households, and cats that have not completed the core three-in-one vaccination course. 

The symptoms of cat flu vary widely, ranging from mild local discomfort to systemic problems affecting the whole body, with different degrees of severity. Identifying these warning signs early is key to seizing the best opportunity for treatment.

Respiratory and eye symptoms:

• Frequent sneezing: This is one of the most typical early symptoms. The cat will sneeze much more often than usual, and may even have several sneezes in a row.  
• Runny nose: Changes in the nasal discharge are an important indicator of the disease progression. In the early stages, it may be clear and watery. If there is a secondary bacterial infection, it may turn yellow-green or become thicker and pus-like. In severe cases, it can block the nostrils and affect appetite.  
• Nasal congestion and abnormal breathing sounds: Thick nasal discharge can cause nasal congestion, making the cat’s breathing sound heavier, and its snoring during sleep may also become louder as a result. In extreme cases, the cat may even breathe through its mouth, which is a dangerous sign of severe illness.  
• Eye symptoms: The eyes are also a major problem area. Cats may develop red eyes, sensitivity to light, frequent blinking and tearing. Eye discharge may change from clear and watery to thick, pus-like eye gunk, making it difficult for the cat to open its eyes. This is usually associated with complications such as conjunctivitis or keratitis.  
• Coughing: Although less common than sneezing, coughing or unusual sounds from the throat may mean the infection has spread from the upper respiratory tract to the lower respiratory tract, such as the trachea.  

Overall condition and behavioural changes in cats with flu

As the infection worsens and affects the whole body, the cat’s behaviour and physical condition will also change significantly:

• Reduced appetite: Nasal congestion can seriously affect a cat’s sense of smell, and smell is crucial for stimulating appetite. In addition, pain from mouth ulcers, which are common in calicivirus infections, may make the cat fussy about food, or even stop eating and drinking altogether.  
• Lethargy and sleepiness: Fighting the virus consumes a great deal of energy, so the sick cat’s activity level will drop significantly. It will spend most of its time sleeping, lose interest in toys or interaction it usually enjoys, and may prefer to hide in quiet corners.  
• Fever: An elevated body temperature is the body’s natural response to infection. Owners may notice that the cat feels unusually warm, and it may also be accompanied by shivering or rapid breathing.  
• Weight loss and poorer coat condition: Due to reduced food intake and the body’s increased energy consumption, the cat’s weight may drop noticeably in a short period of time. At the same time, because it feels unwell, it will groom itself less often, causing the coat to become rough and lose its shine.  

The cost of treating a cat for a cold can range from a few hundred to several thousand Hong Kong dollars, depending on the severity of the condition, the tests required (such as X-rays and pathogen PCR testing), and the length of hospitalisation. A standard outpatient consultation typically costs around $300 to $700, while hospitalisation may cost as much as $600 to $1,500 per day. Faced with this unexpected expense, pet insurance has become an important support for many pet owners.  

10Life also provides professional analysis, helping everyone compare the pet insurance plans offered by major insurers in the market in greater depth.
Further reading:Hong Kong Pet Insurance Comparison 2026: Coverage and Premiums Fully Disclosed (with Exclusive Actuarial Scores)

These plans usually cover eligible medical expenses arising from illness, including upper respiratory tract infections, such as veterinary consultation fees, medication costs, laboratory fees and hospitalisation charges. Pet owners should pay particular attention to the following points when taking out insurance:  

• Waiting period: Most policies include a waiting period for illness (for example, 90 days), and illnesses occurring during the waiting period will not be covered.  
• Exclusions: Pre-existing conditions are usually listed as exclusions. In addition, preventive care (such as vaccinations and routine check-ups) and nutritional supplements are often not covered.  
• Excess and reimbursement percentage: Pet owners must bear the excess, commonly known as the “deductible”, as well as the co-insurance percentage set out in the policy terms (for example, the insurer reimburses 80% and the pet owner pays 20%).  
• Annual benefit limit: The total amount payable in each policy year is capped.

By insuring your cat while it is still healthy, you can ease the burden of heavy medical expenses if it unfortunately falls ill, allowing you to choose the most suitable treatment for your beloved cat with greater peace of mind. 

A cat’s cold is often more worth paying attention to in terms of overall condition and behavioural changes than the visible symptoms alone. Reduced appetite and fussiness are the most common warning signs. In severe cases, your pet may refuse to eat or drink altogether, leading to dehydration and malnutrition. Low spirits and lethargy, with activity levels noticeably lower than usual; a previously lively and active pet may start hiding and avoid interaction. An elevated body temperature or fever, with the body feeling unusually hot to the touch, may be accompanied by shivering or rapid breathing. Weight loss over a short period, poor coat condition, and reduced grooming frequency are all signs of a weakened immune system. Cats naturally hide pain and illness, so when their behaviour changes significantly, it often means discomfort has been present for some time.

In the following situations, do not wait; seek veterinary help immediately:

• Symptoms worsen over time: If the symptoms do not improve over a few days and instead become more severe, for example if nasal discharge becomes thicker, coughing worsens, or breathing sounds become abnormal.  
• Danger signs appear: If a cat completely stops eating or drinking for more than 24 hours, develops breathing difficulties (such as open-mouth breathing or rapid breathing), or becomes extremely lethargic, these are serious signs requiring urgent medical intervention.  
• High-risk groups: For kittens, senior cats, or cats with underlying chronic conditions, even if the initial symptoms appear mild, prompt veterinary advice is strongly recommended. Their condition may deteriorate rapidly within a short time, and early treatment is key to preventing complications.  

Cat colds caused by feline herpesvirus infection may not be fully curable

Feline herpesvirus infection, caused by feline herpesvirus type 1 (FHV-1), is one of the most common causes of cat colds. Once infected, this virus usually remains latent in a cat’s body for life, particularly in nerve tissue such as the trigeminal ganglion. Therefore, in strict terms, the virus itself cannot be completely eliminated, making a state of “full recovery” difficult to achieve.

However, this does not mean that a cat cannot regain good health. After the initial infection, with appropriate care (such as nutritional support, maintaining hydration, and using antiviral medication or antibiotics when necessary to fight secondary bacterial infections), most cats’ acute symptoms (such as sneezing, eye and nasal discharge, fever, and conjunctivitis) will improve significantly or even disappear within 1 to 2 weeks, allowing them to return to normal life.

It is worth noting that research indicates that stress, illness, and environmental changes may reactivate the virus, triggering recurrent symptoms, especially eye-related issues (such as corneal ulcers or chronic conjunctivitis). Therefore, when caring for a pet that has previously been infected with herpesvirus, maintaining a stable, low-stress living environment, a balanced diet, and regular health check-ups is crucial for preventing recurrence.

This article is for general pet health information only and does not replace professional veterinary diagnosis and treatment. If your cat shows signs of discomfort, please consult a veterinarian as soon as possible.

Although sneezing and a runny nose are typical symptoms of cat flu, they are not the only possible causes. The following are common reasons why cats sneeze / catch a sneeze:

• Temporary environmental irritation: dust in the air, cat litter dust, perfume, second-hand smoke, or even the smell of irritating cleaning products can irritate a cat’s nasal mucosa and trigger short, occasional sneezing. In most cases, the symptoms disappear once the source of irritation is removed, and there are no other associated discomforts.  
• Other illnesses: persistent, long-term sneezing, especially if the symptoms are concentrated in one nostril or the nasal discharge is blood-stained, warrants caution as there may be a more complex issue, such as allergic rhinitis, nasal polyps, nasal tumours, or even a root abscess (infection from dental problems may spread upwards into the nasal cavity). These conditions require a veterinarian to carry out detailed imaging or endoscopic examinations for diagnosis.  

In some individual cases, Lysine may provide slight relief for symptoms such as watery eyes and a runny nose. However, it is important to understand that it is not a treatment and may not be helpful for all cases of feline cold; the medical evidence is quite limited. Lysine should only be regarded as a supplementary health product for certain cases, and cannot replace antibiotics or antiviral medication. If a veterinarian assesses it as suitable, use Lysine according to the product instructions and the doctor’s advice; do not self-supplement in large amounts. Many home remedies on the market lack scientific validation, and blind reliance may delay treatment. When it comes to your pet’s health, sound judgement and professional advice are the right approach. Rather than relying on a single nutrient supplement, it is better to strengthen your pet’s immunity in a comprehensive way, from a balanced diet and moderate exercise to reduced stress, laying a solid foundation for good health. 

This English version of this article has been generated by machine translation powered by AI. It is provided solely for reference purposes. In the event of any discrepancy or inconsistency between this translation and the original Chinese version, the Chinese version shall prevail.