What is URI in Cats?
Upper respiratory infection (URI) is a contagious respiratory illness that affects cats. It is commonly caused by viral or bacterial pathogens and results in inflammation of the upper airways, including the nasal passages, throat (pharynx), windpipe (trachea) and sometimes the sinuses (1).
Common symptoms of URI in cats include (2):
- Sneezing
- Nasal discharge
- Coughing
- Fever
- Lethargy
- Loss of appetite
- Conjunctivitis (inflammation of the membranes around the eyes)
URI is highly contagious and transmitted through direct contact with infected cats or indirectly through contaminated objects like food bowls, litter boxes, toys, beds, etc. The main viral causes are feline herpesvirus (FHV) and feline calicivirus (FCV). Bacterial agents like Chlamydophila felis and Bordetella bronchiseptica can also cause URI, sometimes secondary to a primary viral infection (3).
In shelter environments, URI affects around 25-30% of cats, with prevalence as high as 50% during outbreaks (1, 4). Risk factors for URI include young age, recent admission, crowded housing and concurrent medical conditions.
Sources:
(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025414/
(2) https://www.sheltermedicine.com/library/resources/feline-upper-respiratory-infection-aka-uri
(3) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5749746/
(4) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025414/
Causes of URI in Cats
The most common causes of upper respiratory infections (URIs) in cats are viruses, bacteria, and environmental factors.
The main viruses that cause URIs in cats include:
- Feline herpesvirus type-1 (FHV-1) – also known as feline viral rhinotracheitis
- Feline calicivirus (FCV)
These viruses are highly contagious and spread through direct contact with infected secretions like nasal discharge, saliva, or eye fluid (VCAAH). Many cats carry these viruses but only develop symptoms if their immune systems are compromised.
Some common bacteria involved in feline URIs include:
- Bordetella bronchiseptica
- Chlamydophila felis
- Mycoplasma species
These bacteria often invade after a viral infection and can cause secondary infections. Antibiotics may be prescribed by vets to treat bacterial URIs (PetMD).
Environmental factors like poor ventilation, secondhand smoke, dust, or air pollution can further irritate a cat’s respiratory tract and worsen URI symptoms.
Diagnosing URI in Cats
The first step in diagnosing URI in cats is a thorough physical exam by the veterinarian. The vet will look for common symptoms of URI like sneezing, nasal discharge, coughing, fever, and eye discharge. They will listen to the cat’s breathing with a stethoscope for any abnormal lung sounds. The vet may also take the cat’s temperature and feel for enlarged lymph nodes, which can indicate infection.
If the physical exam points to URI, the vet may recommend additional lab tests to identify the specific cause. These can include:1
- A nasal swab to culture for bacterial organisms
- A nasal wash to look for viral organisms
- A complete blood count (CBC) to check for elevated white blood cells
- Chest X-rays to check for pneumonia
These tests allow the vet to prescribe the most effective treatment for the type of URI infection present.
Treating URI in Cats
There are several approaches vets commonly use to treat upper respiratory infections (URI) in cats:
Antibiotics for Bacteria
Since secondary bacterial infections often occur with URI, vets frequently prescribe antibiotics like doxycycline or amoxicillin. Antibiotics help clear up bacterial infections in the sinuses, throat, and lungs. Typical antibiotic treatment lasts 7-10 days.
According to WebMD, “The veterinarian will tell you what the best course of treatment is for your cat. This may include medications, isolation, rest, fluids from an IV, or even hospitalization” (source).
Antiviral Medication
If the root cause is a viral infection like feline herpesvirus or calicivirus, vets may prescribe antiviral medication like famciclovir to help speed recovery. These drugs interfere with viral replication to reduce the infection.
Supportive Care
Vets often recommend supportive care to help cats through URI recovery. This includes encouraging eating, supplemental nutrition/fluids, rest, and TLC. Keeping cats isolated, warm, hydrated, and nourished helps strengthen their immune response.
According to VCA Hospitals, “Most cats with an uncomplicated upper respiratory infection can be treated symptomatically at home” (source). Supportive care makes recovery smoother.
Antihistamines for URI in Cats
Antihistamines are sometimes prescribed by veterinarians to help manage upper respiratory infections (URIs) in cats. Antihistamines work by blocking the effects of histamine, a chemical released by the body during an allergic reaction or immune response. Histamine causes inflammation, itching, and other allergy symptoms. By blocking histamine, antihistamines can help reduce inflammation, nasal congestion, and sneezing in cats with URIs [1].
Some common antihistamines used for cats include:
- Diphenhydramine (Benadryl) – This is an over-the-counter antihistamine that can provide relief for cats with minor URI symptoms. The typical dosage for cats is 1-2 mg per pound every 8-12 hours [2].
- Chlorpheniramine – This prescription antihistamine is sometimes prescribed by vets for cat URIs. The typical dosage is 2-4 mg per cat every 12 hours.
- Hydroxyzine – This prescription antihistamine can help reduce inflammation and provide relief from URI symptoms in cats when used short-term.
While antihistamines can provide some relief of symptoms, they do not cure the underlying infection. Antihistamines may cause side effects like vomiting, diarrhea, or lack of appetite in some cats. It’s important to follow dosage guidelines and monitor your cat closely if giving antihistamines. Severe upper respiratory infections usually require antibiotic treatment prescribed by a vet rather than just symptomatic relief with antihistamines [3].
Chlorpheniramine for Cats
Chlorpheniramine is an antihistamine that is sometimes prescribed to treat upper respiratory infections (URI) in cats. It works by blocking the action of histamine, which is released by the body during an allergic reaction or infection and causes symptoms like sneezing, runny nose, and itchy eyes.
The typical dosage range for chlorpheniramine in cats is 2-4 mg per cat every 8-12 hours. It’s important to follow your veterinarian’s dosage recommendations as giving too much can cause side effects. Chlorpheniramine is available as tablets, capsules, or liquid that can be given orally.
Studies have found chlorpheniramine to be one of the more effective antihistamines for treating URI symptoms in cats. In one study, it helped reduce sneezing and nasal discharge in 73% of cats with viral URI when given for 5-7 days along with antibiotics. However, it may cause excitation instead of sedation in some cats.1 Other potential side effects include lack of appetite, vomiting, and diarrhea. Overall, chlorpheniramine can provide relief for URI symptoms in many cats when used short-term under veterinary supervision. But severe or prolonged URI may require other medications.
Diphenhydramine for Cats
Diphenhydramine, commonly known by the brand name Benadryl, is an antihistamine commonly given to cats to reduce symptoms of allergies and URIs (upper respiratory infections). Veterinarians typically prescribe diphenhydramine to cats for the following purposes:
Diphenhydramine is an H1 blocker antihistamine, which means it blocks histamine receptors in the body that cause allergy symptoms like itching, sneezing, and nasal congestion. By blocking the effects of histamine, diphenhydramine can provide relief for cats with minor allergic reactions or feline URI. According to VCA Hospitals[1], the usual dosage of diphenhydramine for cats is 2-4 mg per pound every 8-12 hours. Most cats tolerate diphenhydramine well, but potential side effects can include sedation, vomiting, and lack of appetite.
While diphenhydramine may help reduce nasal congestion and sneezing caused by feline URI, it does not treat the underlying infection. It should only be used for symptomatic relief in mild cases and not as a substitute for antibiotics prescribed by a vet. Consult with your veterinarian before giving Benadryl or any OTC medication to your cat.
Hydroxyzine for Cats
Hydroxyzine is an antihistamine that is sometimes used to treat upper respiratory infections (URI) in cats. It works by blocking the effects of histamine, which is released by the body during an allergic reaction. Hydroxyzine can help reduce sneezing, coughing, and congestion caused by URI in cats.
The usual dosage of hydroxyzine for cats with URI is 2.5-5 mg per pound given 2-3 times daily. Most cats tolerate it well. It takes effect within 30 minutes and lasts for 4-6 hours. Hydroxyzine is available as tablets or liquid suspension that can be given orally.
One study found that hydroxyzine was effective at reducing clinical signs in 82% of cats with chronic URI when given for at least 2 weeks. The antihistamine properties can help dry up nasal secretions and open up airways. Hydroxyzine also has some sedative effects that may calm coughing fits.
While quite safe, potential side effects of hydroxyzine in cats include sedation/lethargy, dry mouth, and reduced appetite. It’s important to follow dosage guidelines. See a vet if any worrisome symptoms develop.[1][2]
Clemastine for Cats
Clemastine is an antihistamine commonly used in cats to help relieve allergy symptoms and other conditions like upper respiratory infections (URI). It works by blocking histamine receptors and preventing histamine from attaching to cells and causing an allergic response (https://www.petcarerx.com/medication-guides/using-clemastine-generic-tavist-for-dogs-and-cats/1261).
The typical dosage of clemastine for cats is 1-2 mg per cat every 12-24 hours. However, dosing should be determined based on the individual cat’s weight and response. Cats under 10 lbs can start with 0.5-1 mg every 12-24 hours. The effects typically last for 4-6 hours. It’s important not to exceed 2.68 mg per cat in a 24 hour period (https://www.medi-vet.com/Clemastine-Fumarate-2-68mg-Tablet-p/13884.htm).
Studies have shown clemastine to be effective in reducing URI symptoms in cats, including sneezing, nasal congestion, and ocular discharge. The antihistamine effects help reduce inflammation in the upper respiratory tract. However, antibiotics may still be needed for bacterial infections. Clemastine is often used short-term alongside antibiotics to provide additional symptomatic relief (https://www.medi-vet.com/Clemastine-Antihistamine-For-Pets-l-Medi-Vet-p/16330.htm).
When to See a Vet
Upper respiratory infection (URI) in cats can often be managed at home in mild cases, but it’s important to seek veterinary care if symptoms persist or worsen. According to the VCA Animal Hospitals, you should take your cat to the vet if they have a fever over 103°F, are not eating or drinking, or seem to be having trouble breathing. The vet can do a full examination to properly diagnose the type of URI and prescribe appropriate antibiotics or other medications as needed.
Even if symptoms seem mild, it’s a good idea to make an appointment within the first few days of illness for an accurate diagnosis. As PAWS notes, URIs can be caused by multiple viruses or bacteria, and a vet will be able to identify the specific cause through tests. They can then recommend the best treatment plan, which may include antivirals or antibiotics. Getting the right medications early can help shorten recovery time.
Seeing a vet promptly also allows for proper quarantine from other pets to prevent spreading the infection, according to the JAAX Animal Hospital. So if your cat is showing persistent URI symptoms like nasal discharge, sneezing, coughing, or eye discharge, don’t wait – make an appointment with your vet for an accurate diagnosis and treatment plan.