Dr. Tiffany Delacruz, DVM • Chief Executive Officer, RexVet • 2026-07-01 • 10 min read
Why Is My Cat Sneezing? Upper Respiratory Infection Guide — FL, NY & VA
Cat sneezing is usually a feline upper respiratory infection (URI) — herpesvirus, calicivirus, or bacterial. FL/NY/VA vets diagnose and treat by $64.99 video.
Medically reviewed by Dr. Tiffany Delacruz, DVM
A sneezing cat is the #1 respiratory complaint at the vet. Most of the time it's a feline upper respiratory infection (URI) — the cat version of a cold, but with some important differences. Some URIs resolve on their own in a week. Others flare for years or lead to eye ulcers and chronic sinusitis. This guide is for FL, NY, and VA cat parents to know what's normal, what's not, and how to get help fast.
When sneezing is not concerning
- A few sneezes a day, no discharge, no other symptoms
- After cleaning the litter box (dust)
- After introducing a new scent (candle, cleaning product, perfume)
- Seasonal allergies (spring pollen, fall mold)
- After a dental cleaning or dental disease flare (nose-mouth communication)
When sneezing is a URI
- Frequent bouts of sneezing
- Watery or thick discharge from nose or eyes
- Squinting, red or gooey eyes
- Decreased appetite (cats stop eating when they can't smell)
- Lethargy
- Fever (subjective — cat feels hot)
- Recently around other cats (shelter, boarding, new cat, outdoor)
The 3 causes of feline URI
- Feline herpesvirus-1 (FHV-1) — most common. Once infected, the cat carries it for life and flares during stress (moving, new pet, boarding, illness). Eye involvement is common — corneal ulcers are the main complication.
- Feline calicivirus (FCV) — mouth ulcers on the tongue and hard palate are classic. Some strains cause limping in kittens (calicivirus arthritis).
- Bordetella and Mycoplasma — bacterial causes, or secondary bacterial infection on top of viral. Treatable with antibiotics (Clavamox, doxycycline, azithromycin).
Red flags — in-person exam TODAY
- Squinting eye + tearing + cloudy or grey cornea — herpetic corneal ulcer, needs staining + specific eye meds
- Open-mouth breathing — cats don't do this, indicates severe respiratory distress
- Refusal to eat for 48+ hours — hepatic lipidosis risk in cats, especially obese
- Thick yellow/green nasal discharge — bacterial infection
- Any URI in a kitten under 8 weeks — dehydration risk, needs SQ fluids
- Any URI in FeLV+ or FIV+ cat — poor immune response, may need aggressive care
- Lethargy plus fever plus decreased eating together
Home care — what works
- Humid warm room — sit with cat in bathroom with steamy shower running for 10 min, 2-3x/day. Loosens congestion.
- Keep nose gently clean with saline solution and a soft cloth
- Warm food — cats stop eating when they can't smell. Warm wet food, add tuna water or low-sodium chicken broth to boost aroma.
- L-lysine 500mg daily — for herpesvirus flares, may shorten and mild the flare (mixed evidence but low risk)
- Hydration — offer water fountain, wet food, add water to food
- Isolate from other cats until 2 weeks after symptoms resolve
Treatment your vet may prescribe
- Clavamox — broad-spectrum antibiotic, first-line for bacterial URI
- Doxycycline — good coverage for Mycoplasma and Bordetella, also anti-inflammatory in the airway
- Azithromycin — for stubborn upper respiratory or bordetella
- Famciclovir — antiviral for severe herpesvirus flares
- Terramycin ophthalmic ointment — for uncomplicated conjunctivitis
- Idoxuridine or cidofovir eye drops — for herpetic corneal ulcers
- SQ fluids — for dehydrated cats not drinking enough
Florida: heat + humidity + strays
Florida's warm humid year-round climate favors URI transmission and chronic herpesvirus flares. FL outdoor and community cats are heavily exposed — expect FeLV/FIV comorbidity in strays. Prevent overcrowding stress in multi-cat homes to reduce flare frequency.
New York: winter heating stress + shelters
NYC winter heating dries out cat nasal passages and worsens herpesvirus flares. Shelter and rescue adoption is common in NY — expect URI in the first 2-4 weeks after bringing a cat home. Isolate from resident cats until healthy for 2 weeks.
Virginia: outdoor colonies + transitions
VA has many TNR (trap-neuter-return) colonies and outdoor cats. Any newly-adopted VA cat should be assumed FeLV/FIV tested plus URI-carrier. New cats + resident cats introduction is a top trigger for URI flares.
Emergency signals
When to contact a veterinarian
- Squinting eye or cloudy cornea — herpetic corneal ulcer
- Open-mouth breathing (cats don't do this normally)
- Refusal to eat for 48+ hours — hepatic lipidosis risk
- Thick yellow/green nasal discharge
- Any URI in a kitten under 8 weeks
- Any URI in an FeLV+ or FIV+ cat
- Lethargy + fever + decreased appetite together
Frequently asked questions
Why does my cat keep sneezing?
The most common cause is feline upper respiratory infection (URI) — herpesvirus, calicivirus, or bacterial. Once infected with herpesvirus, cats carry it for life and flare during stress. Occasional sneezing with no discharge is often just dust or allergies.
Can a RexVet online vet treat cat URI?
Yes. $64.99 video visits with FL/NY/VA-licensed vets diagnose URI, prescribe Clavamox, doxycycline, or azithromycin, recommend L-lysine, and plan supportive care. Cats with eye ulcers, kittens under 8 weeks, or open-mouth breathing should go in-person.
How long does cat URI last?
Uncomplicated viral URI: 7 to 14 days with supportive care. Bacterial URI on antibiotics: 5 to 10 days of improvement expected. Chronic herpesvirus flares can recur throughout life during stress. Herpetic corneal ulcers need specific eye treatment for 2 to 4 weeks.
Is cat sneezing contagious to other cats?
Yes. Feline URI spreads by direct contact and shared food, water, and litter. Isolate a sneezing cat from other cats for 2 weeks past symptom resolution. Herpesvirus and calicivirus are NOT contagious to humans or dogs.
Does L-lysine really help herpes flares?
Evidence is mixed. Some studies show shorter and milder herpesvirus flares with 500mg daily L-lysine, others show no benefit. Low risk, low cost, and widely recommended by feline vets as adjunctive therapy. Not a replacement for antibiotics if bacterial infection is present.
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About the author
Dr. Tiffany Delacruz, DVM
Chief Executive Officer, RexVet
Licensed veterinarian and CEO of RexVet (Rex Vets Inc.). Practicing across Florida, New York, and Virginia via licensed telehealth. Reviews every clinical article on RexVet before publication.