Many cat upper respiratory infection symptoms resemble those of the common cold, and in many cases, cats recover with rest, supportive care, and plenty of hydration. However, upper respiratory infections can become more serious if left untreated—especially in kittens, senior cats, and cats with weakened immune systems.

One of the biggest challenges for pet owners is recognizing when a mild illness can be managed at home and when it requires immediate veterinary care. While occasional sneezing or watery eyes may not be cause for alarm, warning signs such as loss of appetite, difficulty breathing, thick nasal or eye discharge, extreme lethargy, or sudden behavioral changes should never be ignored.

In this guide, you'll discover the 10 warning signs of a cat upper respiratory infection every pet owner should know, practical tips to help your cat stay comfortable during recovery, and the key symptoms that signal it's time to contact—or visit—your veterinarian. By recognizing these signs early, you can make informed decisions, seek treatment when needed, and give your cat the best possible chance of a full and speedy recovery.

10 Cat Upper Respiratory Infection Symptoms You Should Never Ignore

Not every cat with an upper respiratory infection will develop the same symptoms. Some may only experience mild sneezing, while others can become noticeably ill within a day or two. That's why it's important to look for multiple symptoms, worsening signs, or unusual changes in your cat's behavior.

Recognizing these cat upper respiratory infection symptoms early can help you determine whether supportive home care is appropriate or if your cat needs prompt veterinary attention.

1. Frequent Sneezing

An occasional sneeze is usually nothing to worry about. However, repeated sneezing—especially when accompanied by a runny nose or watery eyes—is often one of the earliest signs of an upper respiratory infection.

Watch for:

  • Frequent sneezing episodes throughout the day

  • Sneezing accompanied by mucus or nasal discharge

  • Sneezing that continues for more than two or three days

2. Runny Nose or Thick Nasal Discharge

Clear, watery nasal discharge is common during the early stages of an infection. As the illness progresses, the mucus may become thick, yellow, or green, which can indicate a secondary bacterial infection that requires veterinary treatment.

Signs to watch for include:

  • Constant nasal dripping

  • Thick or sticky mucus

  • Crusting around the nostrils that makes breathing more difficult

3. Watery, Red, or Swollen Eyes

Upper respiratory infections often affect the eyes as well as the nose. Healthy eyes should appear bright and clear. Excessive tearing, redness, swelling, or discharge may indicate that the infection is spreading or becoming more severe.

Common symptoms include:

  • Excessive tearing

  • Yellow or green eye discharge

  • Red, swollen, or irritated eyes

  • Squinting or keeping one eye closed

4. Nasal Congestion or Noisy Breathing

Just like people with a bad cold, cats can develop nasal congestion that makes breathing uncomfortable. Because cats rely heavily on their sense of smell, even mild congestion can reduce their appetite and overall comfort.

Look for signs such as:

  • Snorting or snuffling sounds

  • Loud or congested breathing through the nose

  • Noisy breathing while resting or sleeping

5. Loss of Appetite or Refusing Food

A reduced appetite is one of the most important warning signs to watch for. Cats depend on their sense of smell to enjoy food, so a blocked nose can make even their favorite meals seem unappealing.

Pay close attention if your cat:

  • Eats significantly less than usual

  • Sniffs food but walks away

  • Refuses food for 24 hours or longer

Kittens, senior cats, and overweight cats are especially vulnerable to complications from not eating. Contact your veterinarian promptly if your cat refuses food.

6. Lethargy or Unusual Hiding

When cats don't feel well, they often become less active and more withdrawn. A normally social cat may hide for long periods or lose interest in activities they usually enjoy.

Behavioral changes may include:

  • Sleeping much more than usual

  • Little or no interest in playing

  • Hiding under furniture or avoiding people and other pets

7. Fever (Often Accompanied by Low Energy)

It's difficult to confirm a fever without taking your cat's temperature, and warm ears or a dry nose aren't reliable indicators. Instead, look for changes in your cat's overall behavior that commonly occur with a fever.

Possible signs include:

  • Low energy or unusual tiredness

  • Poor appetite

  • Wanting to be left alone

  • Feeling warmer than normal when handled

If you suspect your cat has a fever and they're acting unwell, contact your veterinarian for guidance.

8. Coughing or Gagging

Unlike people, cats rarely cough. Persistent coughing or repeated gagging should never be ignored, as it may indicate irritation caused by mucus or a more serious respiratory problem.

You may notice your cat:

  • Coughing repeatedly

  • Gagging after swallowing mucus

  • Making frequent throat-clearing sounds

Seek veterinary advice if coughing is persistent or accompanied by breathing difficulties.

9. Mouth Ulcers or Excessive Drooling

Some viral infections, particularly feline calicivirus, can cause painful ulcers inside the mouth. These sores can make eating and grooming uncomfortable, often leading to reduced food intake.

Signs include:

  • Excessive drooling

  • Bad breath

  • Pawing at the mouth

  • Difficulty chewing or swallowing food

Because painful mouth ulcers can quickly lead to poor nutrition and dehydration, veterinary care is recommended.

10. Difficulty Breathing or Open-Mouth Breathing (Medical Emergency)

Difficulty breathing is the most serious symptom of all and requires immediate veterinary attention.

Healthy cats breathe quietly through their noses. If your cat begins breathing with an open mouth, appears to be struggling for air, or is breathing much faster than normal, treat the situation as an emergency.

Seek emergency veterinary care immediately if your cat has:

  • Open-mouth breathing

  • Rapid or labored breathing

  • Blue, gray, or very pale gums

  • Extreme weakness, collapse, or unresponsiveness

Do not wait to see if these symptoms improve on their own.

Safe Home Care Checklist

If your cat has mild symptoms and your veterinarian recommends home care, these supportive measures can help keep them comfortable while they recover:

  • Keep your cat indoors and away from other cats to prevent spreading the infection.

  • Gently clean eye and nasal discharge with a warm, damp cloth or cotton pad.

  • Offer warmed wet food to enhance the aroma and encourage eating.

  • Promote hydration by providing fresh water at all times and offering wet food regularly.

  • Increase humidity by allowing your cat to spend a few minutes in a steamy bathroom (never expose them to direct hot steam).

  • Use only medications prescribed by your veterinarian. Never give human cold or flu medications, as many are toxic to cats.

  • Monitor your cat closely each day, paying attention to appetite, water intake, breathing, activity level, and overall behavior. If symptoms worsen or fail to improve, contact your veterinarian promptly.

Medical Disclaimer

This article is intended for educational purposes only and should not replace professional veterinary advice, diagnosis, or treatment. If your cat has difficulty breathing, refuses food, becomes severely lethargic, or their condition worsens rapidly, seek veterinary care immediately.

When to See a Veterinarian

It isn't always easy to tell whether cat upper respiratory infection symptoms can be managed at home or require professional medical care. While many mild infections improve with supportive care, others can worsen quickly—particularly in kittens, senior cats, pregnant cats, and those with weakened immune systems.

If you're ever unsure, it's always safest to contact your veterinarian. A brief description of your cat's symptoms can help determine whether home monitoring is appropriate or if an examination is needed.

Contact Your Veterinarian Promptly If Your Cat:

Schedule a veterinary visit or call your clinic as soon as possible if your cat:

  • Stops eating or drinking. Cats rely heavily on their sense of smell to stimulate their appetite. A congested nose can reduce their interest in food, but going too long without eating can lead to serious health complications.

  • Has symptoms that persist for more than a few days or continue to worsen. Ongoing sneezing, worsening congestion, or increasing eye and nasal discharge may indicate that the infection isn't resolving on its own.

  • Develops thick yellow or green discharge from the eyes or nose. This can be a sign of a secondary bacterial infection that may require veterinary treatment.

  • Is a kitten, senior cat, pregnant cat, or immunocompromised. These cats are at a higher risk of developing complications and should be evaluated sooner, even if their symptoms initially appear mild.

A quick call to your veterinary clinic can help you decide whether your cat should be seen the same day or whether careful monitoring at home is appropriate.

Seek Emergency Veterinary Care Immediately If Your Cat:

Some cat upper respiratory infection symptoms require immediate emergency treatment and should never be ignored.

Go to the nearest emergency veterinary hospital immediately if your cat:

  • Has open-mouth breathing or is struggling to breathe. Healthy cats normally breathe quietly through their noses. Open-mouth breathing is a medical emergency.

  • Has blue, gray, or very pale gums. These changes may indicate that your cat isn't getting enough oxygen.

  • Collapses, becomes extremely weak, or is difficult to wake. Severe weakness or unresponsiveness is not a normal part of a respiratory infection.

  • Cannot eat or drink and shows signs of dehydration. Warning signs include dry or sticky gums, sunken eyes, reduced skin elasticity, and profound weakness.

Do not wait to see if these symptoms improve on their own. Prompt veterinary treatment can be lifesaving, especially for young kittens, older cats, and those with underlying medical conditions.

A simple rule to remember: If your cat is breathing comfortably, eating, drinking, and behaving relatively normally, it's often reasonable to monitor them closely while staying in contact with your veterinarian. However, if your cat is struggling to breathe, refusing food, becoming dehydrated, or deteriorating rapidly, seek veterinary care immediately.

Frequently Asked Questions

Can a Cat Recover From an Upper Respiratory Infection Without Antibiotics?

Yes—many cats recover without antibiotics. Most cat upper respiratory infection symptoms are caused by viral infections, such as feline herpesvirus or feline calicivirus. Because antibiotics only treat bacterial infections, they won't cure the underlying viral illness.

Instead, recovery usually depends on supportive care, including:

  • Keeping your cat comfortable, warm, and well hydrated

  • Encouraging them to eat by offering warmed wet food

  • Gently cleaning discharge from the eyes and nose

  • Following your veterinarian's recommendations for monitoring and treatment

If your veterinarian suspects a secondary bacterial infection—for example, because of thick yellow or green discharge, persistent fever, or worsening symptoms—they may prescribe antibiotics. Never give your cat leftover antibiotics or human medications unless your veterinarian specifically instructs you to do so.

How Long Does a Cat Upper Respiratory Infection Usually Last?

Most mild upper respiratory infections begin to improve within 7 to 21 days with appropriate supportive care. Recovery time varies depending on your cat's age, overall health, immune status, and the cause of the infection.

Cats infected with feline herpesvirus often become lifelong carriers. Even after recovering, the virus can remain dormant and flare up again during periods of stress, illness, or immune suppression.

If your cat's symptoms fail to improve after several days, become more severe, or new symptoms develop, contact your veterinarian for further evaluation.

Is a Cat Upper Respiratory Infection Contagious?

Yes. Most upper respiratory infections spread easily between cats through direct contact with respiratory secretions or by sharing contaminated items, such as food and water bowls, litter boxes, bedding, toys, or grooming tools.

To reduce the risk of spreading the infection:

  • Isolate your sick cat from other cats whenever possible.

  • Wash your hands after handling an infected cat.

  • Clean and disinfect shared bowls, litter boxes, bedding, and other frequently used items.

  • Wait until your sick cat has fully recovered before introducing new cats into the household.

The good news is that the viruses and bacteria responsible for most feline upper respiratory infections are not contagious to humans. However, they can spread rapidly in shelters, catteries, and multi-cat homes.

Conclusion

Most cat upper respiratory infection symptoms improve with supportive care, patience, and close monitoring. However, recognizing the warning signs of a more serious illness—and knowing when to contact your veterinarian—can make a significant difference in your cat's recovery.

If your cat develops difficulty breathing, refuses food, becomes unusually lethargic, or their symptoms continue to worsen, don't delay seeking veterinary care.

Bookmark this guide for future reference, so you'll know what to watch for and when it's time to seek professional help. Early action gives your cat the best chance of a safe, smooth, and speedy recovery.