Your Cat’s Allergies: Diagnosis, Treatments, and Beyond

Cats are notorious for hiding illnesses, but allergy symptoms might be the easiest for you to uncover.

When we think about allergies and cats, it’s usually about humans. Your cat can have allergies to common irritants, foods, and the seasonal type too.

Each type of allergy has its methods for diagnosis that either you or your veterinarian can assess.

Learn the signs, differences, and treatments to help your kitty cope with their allergies.

How Common are Allergies in Cats?

Cats have sensitive upper respiratory systems, so allergies are more common than owners think.

According to PetMD, Your cat can also have food-related allergies, and in some cases, a cluster of allergy-related conditions.

What are the Types of Cat Allergies?

  • Food
  • Pollen
  • Dust
  • Mold
  • Fleas
  • Mites

Regardless of allergy type, diagnosing is often a complex process with a lot of trial and error. Sometimes, your cat will have multiple allergies too, which makes the diagnosis more difficult for your vet.

What are the Signs of Allergies in Cats?

Symptoms can vary as you can see in the video above, but they’re similar to what you’d expect for yourself. Remember, cats have multiple types of allergies too, and their reactions can vary.

For an in-depth look, you can watch a free webinar by the Royal School of Veterinary Medicine in Edinburgh.

The webinar shows the extensive trial and error you and your vet will likely go through before reaching a full and accurate diagnosis.

Here are a few of the symptoms they cover.

  • Excessive scratching
  • Loss of fur
  • Atopic dermatitis, such as rash and/or hives
  • Excessive sneezing with or without clear discharge
  • Depression
  • Pain
  • Swelling
  • Skin redness
  • Gastrointestinal issues like vomiting and diarrhea
  • Anaphylactic shock
  • Life-threatening and requires immediate intervention

Below we can have another look at the classic signs of a cat with a food allergy. You can see the kitty has many of these symptoms.

The veterinarian also discusses the common food allergens lurking in your cat’s diet like corn, wheat, and soy.

How Do I know My Cat Has Allergies and Not a Cold or Infection?

For upper respiratory symptoms, you might not be able to tell the difference.

However, pay attention to these telltale symptoms.

  • Excessive nasal discharge, especially yellow or green
  • Fever
  • Coughing
  • Ulcers
  • Congestion

I Suspect Allergies. Should I Take My Cat to the Vet?

Anytime you believe your cat is ill, you should take them to the veterinarian to rule out other conditions.

What Can Mimic Feline Allergies:

  • Feline immunodeficiency virus (FIV)
  • Feline infectious peritonitis
  • Feline Leukemia
  • Bordetella
  • Mycoplasma

My Cat’s Always Eaten the Same Food. How Could it Cause Allergies?

This is a common misconception with feline allergies (canine too). Allergies can develop suddenly or over time, which answers the question.

Scientists and vets tend to disagree on how and why a cat’s body will suddenly see a substance as an invader, but they both agree that it does happen.

We Have Multiple Cats but Only One has Food Allergies?

Not every cat will have the same allergies or allergies period. However, in a multi-cat household, you should feed all of the cats the same food and treats if possible.

Otherwise, you might need to feed your non-allergic cats in an area off-limits to your cat with food allergies.

Some cats have severe allergies to the point where breathing in the allergen will trigger a response. In multiple pet households, this can pose a real threat.

One of our staff has a dog with severe food allergies, for example. He can’t have chicken, turkey, pork, beef, wheat, corn, soy, eggs, or rice. When she adopted a cat, she had to feed the cat a similar ingredient diet (strictly fish-based cat food) to avoid triggering her dog’s allergies.

It doesn’t take much either to set off their allergies, so cross contamination is a real concern for your kitty’s overall wellbeing.

How to Treat Your Cat’s Allergies

After diagnosis, you’ll be able to treat your cat’s allergies at home with medication, dietary changes as needed, and possibly changes in your household. It will depend on the type and/or cause.

For example, a dietary allergy will require a new food free of the allergen(s). You might still need to treat symptoms temporarily until you find one that works for them.

Over the counter, antihistamines seem to work well for itching and as a skin anti-inflammatory.

Steroids are another option, but they will require a prescription and can introduce new worries. Which medication your veterinarian recommends will likely reflect the severity of their allergies.

What is Zyrtec and Why Would My Cat Need It?

Zyrtec or the generic Certizine is the active antihistamine ingredient in Zyrtec. Cats with seasonal, food-related, and environmental allergies might benefit from the medication.

According to PetMD, Vets are also choosing it for more serious allergy-related conditions like asthma and eosinophilic diseases where long-term steroids used to be their go-to.

Will Zyrtec Work for Your Cat’s Allergies?

Some veterinarians prefer zyrtec since it’s both an antihistamine and anti-inflammatory. Combined with its low risks, it makes a good choice for treating most cats.

Are Cats That Should Avoid Zyrtec?

Yes, some cats shouldn’t take it unless your veterinarian says it’s okay.

Avoid using Zyrtec:

  • Senior cats
  • Thyroid issues
  • Heart disease
  • Kidney disease
  • Liver disease
  • Pregnant or nursing queens
  • Seizures or seizure disorder
  • Difficulty using the bathroom

If your cat currently takes medications and/or supplements, you should also contact your veterinarian to avoid drug interactions.

Currently, Zyrtec and drugs affecting the central nervous system can cause issues. Some cats take certain types of drugs to combat anxiety and stress, which fall under that category.

Zyrtec Can Also Treat Feline Allergic Asthma

According to AmericanVeterinarian, Allergic asthma is prevalent in cats, but researchers can’t explain why.

Symptoms range from sneezing, wheezing, and coughing, and oftentimes, a cat experiences all three. What they do know is early and constant treatment allow cats to live nearly symptom-free lives.

Cats can have this along with other conditions, especially a cold, so you should have your kitty checked by a vet to rule it out if you suspect allergies.

Does Using Zyrtec for My Cat’s Allergies Really Have No Side Effects?

According to VcaHospitals, Many veterinarians and studies show there are fewer side effects with Zyrtec than other available antihistamines on the market in the treatment of allergies. Sleepiness is common in cats with higher doses.

According to the National Center for Biotechnology Information, This study on nine cats reported zero side effects.

What’s the Dosage if Using Zyrtec for Cats?

Dosing will greatly depend on whether you choose an oral syrup or a tablet. From experience, unless your cat will take a pill easily, you’re better off using the liquid. Even if you crush the pill and sprinkle it on wet food, your cat might refuse it or eat around it.

Some cats will take it once a day. Others will need it twice a day. Your veterinarian will let you know how often.

According to the National Center for Biotechnology Information, The actual amount can vary too. One study used 5mg per cat to treat allergic skin disease (pruritus) from atopic dermatitis and food allergies. However, you should consult your veterinarian for the proper dosage.

How Soon Will Zyrtec Work on My Cat’s Allergies?

Within the hour to first two hours is the common consensus. Every pet is slightly different, so don’t be surprised if you see symptom improvement quicker or a litter later.

If four to five hours pass with no progress, contact your veterinarian. They might adjust your dose or have you wait for the next. In addition, they’ll likely want in-depth information of how you gave the medicine to ensure you did it correctly.

What if I Miss a Dose? Should I Double the Next?

Don’t give an additional dose without permission from your veterinarian. Just give your cat their next dose at the scheduled time.

Why Should I Consider Zyrtec for My Cat’s Allergies Over Steroids?

Other than antihistamines, your cat’s option will be steroids. Long-term steroid use can pose problems, but you will see short-term side effects too. According to the VCA Hospitals:

Common Steroid Side Effects

  • Weight gain
  • Loss of energy
  • Increased thirst and hunger
  • Infections that won’t heal
  • UTI
  • Predisposition to diabetes
  • Possible obesity
  • Muscle weakness
  • Prone to fungal infections
  • Prone to bacterial infections
  • Cushing’s disease
  • And more

We already learned Zyrtec can effectively replace steroid treatments for most cats and has no known side effects.

By considering it over steroids, you’re reducing the risk of at least ten common side effects. That alone might make it worth opening a dialogue with your vet about Zyrtec.

Closing Thoughts on Your Cat’s Allergies and Treating with Zyrtec

If your cat displays allergy symptoms, you should bring them into your veterinarian’s office for a thorough checkup. Many serious conditions mimic allergies, so it’s best to rule those out.

Openly communicate with your vet about your cat’s diet, environmental allergens, and medical history. Through medical testing and trial and error, you can both uncover the cause of the allergies.

In the meantime, you can consider treating your kitty’s symptoms with an antihistamine like Zyrtec or asteroid. You can also make changes to their diet and environment if they’re contributing factors.

Soon your kitty should be on the mend, itch-free, and one happy cat.