Upper Respiratory Infection in Cats — Causes and Treatment

What Is a Cat Upper Respiratory Infection?

A cat upper respiratory infection — often called a feline URI — is an infection of the nose, throat, and sinuses. Think of it as the cat version of a human cold, though the specific viruses and bacteria involved are different (and aren't transmissible to people in most cases). URIs are extremely contagious between cats, which is why they spread so rapidly in shelters, catteries, and multi-cat households.

Most feline URIs are caused by viruses, but bacteria can also be primary agents or secondary invaders that complicate a viral infection. While the majority of cases are mild and self-limiting in healthy adult cats, URIs can become dangerous for kittens, senior cats, and immunocompromised felines. Understanding the underlying cause helps determine the best treatment approach.

Common Causes of Upper Respiratory Infections in Cats

Several pathogens can trigger a feline URI, but two viruses account for roughly 80–90% of all cases. Here's a breakdown of the most common culprits:

Recognizing Cat Cold Symptoms: What to Watch For

One of the trickiest things about feline URIs is that early symptoms can look like "just a little sneeze." But if you know what to watch for, you can catch an infection early and get your cat the care they need before things escalate. Cat cold symptoms typically appear 2–10 days after exposure to an infected cat.

Here are the most common signs of a cat upper respiratory infection:

• Sneezing — frequent, repeated sneezing is often the first noticeable sign
• Runny nose — discharge may be clear at first, then become thick and yellowish-green
• Watery or goopy eyes — may include squinting, redness, or swollen conjunctiva
• Congestion — your cat may sound "stuffy" and breathe through their mouth
• Loss of appetite — cats rely heavily on smell to eat, and congestion kills their appetite
• Lethargy — less playfulness, more sleeping than usual
• Fever — you may notice warm ears, but a vet thermometer is needed to confirm
• Drooling or mouth ulcers — especially common with calicivirus infections
• Coughing — less common but can occur, especially with bacterial involvement

How Veterinarians Diagnose a Feline URI

In most cases, your vet will diagnose a feline URI based on a physical examination and your cat's symptoms — there's usually no need for extensive testing for a straightforward case. Your vet will check your cat's temperature, listen to their lungs, examine the eyes and mouth, and assess hydration levels.

However, additional diagnostics may be recommended in certain situations:

• PCR testing — swabs from the eyes, nose, or throat can identify the specific pathogen, which is especially useful for chronic or recurrent cases
• Blood work — a complete blood count (CBC) can reveal if your cat is fighting a significant infection and rule out other illnesses like FeLV or FIV
• Chest X-rays — recommended if your vet suspects the infection has progressed to pneumonia
• Eye staining (fluorescein test) — to check for corneal ulcers, which are common with feline herpesvirus

Knowing the specific pathogen doesn't always change treatment for mild cases, but it becomes important for cats with chronic, severe, or recurring infections.

Treatment Options for Cat Upper Respiratory Infections

The treatment for a cat upper respiratory infection depends on the severity, the suspected cause, and your cat's overall health. Since most URIs are viral, antibiotics won't cure the underlying infection — but they're often prescribed to prevent or treat secondary bacterial infections that pile on when your cat's immune system is already fighting a virus.

Veterinary Treatments

Home Care and Supportive Remedies

Mild cases of cat sneezing and runny nose can often be managed at home with supportive care alongside any medications your vet prescribes. Here's what you can do to help your sniffly feline feel better:

1. Create a steam room: Run a hot shower and sit with your cat in the steamy bathroom for 10–15 minutes. The moisture helps loosen congestion — just like a humidifier works for us.
2. Use a humidifier: Place a cool-mist humidifier near your cat's resting area to keep nasal passages moist.
3. Keep eyes and nose clean: Gently wipe discharge from your cat's face with a warm, damp cloth several times a day. This helps them breathe and smell their food.
4. Offer smelly, warming food: Heat up canned food slightly in the microwave (test the temperature!) to release aromas. Try extra-stinky options like tuna-flavored food or low-sodium chicken broth.
5. Ensure hydration: Offer fresh water in multiple locations. A cat water fountain can encourage drinking. You can also add water to wet food to sneak in extra fluids.
6. Provide a quiet, warm space: Isolate your sick cat from other pets in a comfortable room with their bed, litter box, food, and water.
7. Consider L-lysine supplementation: Some vets recommend lysine to help manage herpesvirus, though research results are mixed. Always check with your vet first.

Recovery Timeline: How Long Does a Cat URI Last?

For most healthy adult cats, a feline URI will run its course in 7 to 14 days. You should start seeing improvement within the first week, especially with supportive care. However, some important caveats apply:

• Kittens may take longer to recover and are at higher risk for complications like pneumonia
• Senior cats or those with chronic conditions (kidney disease, diabetes) may have prolonged recovery
• FHV-1 carriers may experience recurring flare-ups throughout their life, especially during periods of stress (moving, new pets, boarding)
• If symptoms last more than 2–3 weeks or worsen after initial improvement, contact your vet — a secondary infection or other underlying issue may be at play

One important thing to know: cats infected with feline herpesvirus become lifelong carriers. The virus goes dormant in the body and can reactivate when the cat is stressed. This doesn't mean your cat will be sick forever — it means occasional flare-ups are possible and managing stress is part of long-term care.

Preventing Upper Respiratory Infections in Cats

An ounce of prevention is worth a pound of cure — and that's especially true for contagious illnesses like feline URIs. While you can't create a completely germ-free bubble for your cat, you can dramatically reduce their risk with a few smart strategies.

• Vaccination: The FVRCP vaccine (the standard "core" cat vaccine) protects against both feline herpesvirus and calicivirus. It won't prevent infection 100%, but it significantly reduces the severity and duration of illness. Keep your cat's vaccines up to date.
• Isolate new cats: When bringing a new cat or kitten home, quarantine them in a separate room for 10–14 days and monitor for symptoms before introducing them to resident cats.
• Minimize stress: Stress weakens the immune system and can trigger FHV-1 reactivation. Provide enrichment, routine, hiding spots, and vertical space — especially in multi-cat homes.
• Practice good hygiene: Wash your hands between handling different cats. Disinfect food bowls, litter boxes, and bedding regularly. Common disinfectants like dilute bleach (1:32) are effective against most URI pathogens.
• Keep cats indoors: Indoor cats have much less exposure to infected strays and community cats.
• Reduce crowding: In multi-cat households, ensure each cat has their own food bowl, water source, and litter box (plus one extra). Overcrowding is the number one risk factor in shelters.

Special Considerations for Kittens and Multi-Cat Homes

If you have a kitten with a URI, take it seriously. Kittens under 8 weeks old have immature immune systems and can go from sneezing to critically ill in 24–48 hours. Dehydration, weight loss, and pneumonia are real risks. Don't wait and see — get them to a vet at the first sign of illness. Orphaned or bottle-fed kittens are especially vulnerable since they didn't receive maternal antibodies.

In multi-cat households, a single URI can sweep through the entire home like wildfire. At the first sign of symptoms in one cat, isolate them immediately. Use a separate room with their own litter box, food, and water. Change your clothes and wash your hands before interacting with healthy cats. While it's heartbreaking to separate them, it's the best way to protect the rest of your fur family.

If you've recently adopted a cat from a shelter and they develop cat sneezing and runny nose within the first week or two, don't panic — this is incredibly common. The stress of shelter life and the transition to a new home often triggers URI symptoms. With proper care and a calm environment, most newly adopted cats bounce back beautifully.

When a URI Might Be Something Else

Not every sneeze means a URI. Several other conditions can mimic cat cold symptoms, and it's worth knowing when something else might be going on:

• Allergies: Cats can be allergic to dust, pollen, mold, and household fragrances. Allergic sneezing tends to be seasonal or constant, without fever or colored discharge.
• Foreign body: A blade of grass or small object stuck in the nasal passage can cause one-sided sneezing and discharge.
• Dental disease: Severe tooth root infections can cause nasal discharge and sneezing, often on one side.
• Nasal polyps or tumors: Chronic, worsening nasal symptoms — especially in older cats — warrant further investigation.
• Fungal infections: Less common but possible, especially in certain geographic regions. Cryptococcosis is the most common feline fungal nasal infection.

If your cat's symptoms are chronic (lasting more than 3–4 weeks), one-sided, or not responding to treatment, your vet may recommend advanced diagnostics like a CT scan, rhinoscopy, or biopsy to rule out these other conditions.