Scratch, scratch. Wheeze, wheeze. Does your cat have allergies? If so, good news—they’re manageable! Let’s explore the signs and symptoms of allergic reactions in cats, so you will know how to help Mr. Whiskers find relief.

In this blog about cat allergies, we’ll look at:

• Reasons cats develop allergies

• Signs and symptoms of allergies in cats

• What to do for cats who have allergies

• When to seek emergency veterinary care

Common allergy triggers in cats

Your pointy-eared pal has been looking a little off lately. The fact about felines is, they can develop allergies to a variety of triggers, just like people can. Some allergies show up gradually, while others can cause sudden, severe reactions that require immediate emergency care. So if your furry buddy is showing new symptoms, it’s not something to ignore. Knowing when to take your cat to the emergency vet is crucial to his health and comfort.

So, why does your cat have allergies? Some substances that cats come in contact with can cause an allergic reaction.

Cats can be allergic to these things:

• Certain foods: Your cat may have access to some foods that can bring on an allergic reaction:

  • It’s possible your kitty has developed an allergy to his regular brand of cat food.

  • Perhaps your curious cat found food while exploring the trash.

  • Maybe well-meaning people fed your cat table scraps.

• Environment: Yes, your cat’s surroundings can be the cause of allergies.

  • Could a different brand of laundry detergent be the culprit? If your cat curls up in clothing that’s fresh from the dryer, or even hops into an empty laundry basket, new scents can linger and cause a reaction.

  • A new carpet could be the problem. Carpet fibers are hardly visible but can cause allergic reactions in cats.

  • Scented candles or a room deodorizer can be allergy triggers in cats.

  • Stinging insects or fleas: Ugh, bugs! If your cat gets stung by a bee or has fleas, he'll likely get a little itchy and scratchy.

• Vaccinations: A cat can develop an allergic reaction from a recent vaccine shot

  • While it’s important to get your cat on a routine vaccination schedule, be on the lookout for any allergic reaction that might develop after a vaccine, like swelling at the injection site.

7 allergy symptoms in cats

Recognizing the symptoms of allergies in cats is step one in helping your feline friend find some relief. Below are the seven most common cat allergy symptoms to look out for, when they’re typically mild, and when they might be a sign of something more serious - knowing when to seek emergency veterinary care can help you act quickly and keep your cat safe. 

Symptom 1: Skin irritation (dermatitis) in cats

Skin irritation, or dermatitis as it’s clinically known, can be a hallmark sign of an allergic reaction in cats.

Common dermatitis symptoms in cats include:

• Itchiness

• Redness

• Painful or swollen skin

Cats with irritation in their skin can show specific behaviors:

• Biting at the site of discomfort

• Licking incessantly

• Scratching frequently

How to help your cat's skin irritation at home:

If the irritation is mild, you can try limiting allergen exposure, checking for fleas, and keeping your cat from scratching and biting his skin. Avoid using medications or topical creams/ointments - many are unsafe for cats. 

When to worry about cat's skin problem:

Most mild itching isn’t an emergency, but sudden swelling, hives, or intense, nonstop scratching can signal an acute allergic reaction. If your cat is scratching so much that they’re breaking the skin, bleeding, or becoming distressed, don’t hesitate - it’s safest to head to an emergency vet.

Symptom 2: Eye swelling, discharge, or irritation

Irritated eyes point to an allergic reaction. If you notice your cat exhibiting any of the below symptoms, try to get him to stay still so you can see what’s going on.

Common signs of an allergic reaction in your cat:

• Red, swollen, watery eyes

• Squinting or blinking excessively 

• Pawing at his eyes or trying to rub his face on furniture 

• Eye discharge

How to help your cat's eye irritation at home:

If your kitty will let you, you can try to check for obvious debris near the eyelid and gently wipe the eye area with a clean, damp cotton pad to remove any allergen particles or mild discharge. Use plain warm water only—no eyedrops or human products. If the symptoms improve in an hour or two, the irritation may have been mild. If it continues, see your nearest VEG ER for Pets.

When to worry:

If you notice rapid eyelid swelling, severe redness, or discharge that appears suddenly after exposure to a new material (like a plant, cleaning product, candle, or insect bite), it’s time for emergency care. Swelling around the eyes can progress quickly, and you don’t want to mess with your cat’s ability to see.

Symptom 3: Ear infection

Did you know that allergic reactions can lead to ear infections in cats? Allergies can cause inflammation in the ears, which can then lead to symptoms.

Common ear infection symptoms in cats:

• Scratching at the ears

• Head shaking 

• Redness

• Wax buildup 

• Noticeable odor coming from the ears

Contact your local VEG animal hospital to have your cat examined by a professional ER vet. They’ll help you find the cause of the allergy, and resolve symptoms.

How to help your cat's ear infection at home:

Keep the ear dry and remove visible surface debris only. If there’s light dirt or wax on the outer flap, you can wipe it with a soft, damp cloth. Try to keep your kitty from pawing at his ears - cats are prone to secondary infections when they scratch their ears excessively.

Apart from keeping your cat comfortable and trying to prevent the infection from worsening, there’s not much you can do at home if your cat’s ear is infected - untreated, a bacterial infection can result so it’s best to a VEG emergency vet to clear it up. 

When to worry:

If you notice a swollen ear flap, loss of balance, head tilting, or sudden pain when you touch your kitty’s ears, it’s time to seek emergency care immediately. These may indicate infection or more serious inflammation that needs urgent treatment.

Symptom 4: Gastro upset in cats: vomiting or diarrhea

A more significant allergic reaction in cats can sometimes manifest as gastrointestinal issues. Does your cat seem extra finicky lately, or has he lost interest in food? Some allergies, especially food-related ones, cause digestive upset.

Symptoms of gastrointestinal upset in cats include: 

• Diarrhea

• Significant change in appetite

• Vomiting

How to help your cat's stomach upset at home:

You can try switching to a more bland, easily-digestible cat food until symptoms improve, or introducing a cat-safe probiotic into her diet. Make sure your cat is drinking water and provide a safe, quiet space for her to rest. 

When to worry:

If your cat is vomiting repeatedly, becomes weak and wobbly, or has trouble breathing, head to your emergency vet immediately. Gastrointestinal symptoms combined with facial swelling or respiratory changes can indicate anaphylaxis - a severe allergic reaction that needs immediate medical attention. Bring your cat to VEG asap if you notice these signs. 

Symptom 5: Sneezing and nasal discharge in cats

If your cat breathes in something he’s allergic to, it can irritate his nasal passages. Some common offenders include environmental allergens like pollen, dust, and mold.

Here are some allergy signs in cats to look out for: 

• Frequent sneezing

• Congestion

• Runny nose with clear, watery nasal discharge

  
  

How to help your cat's sneezing and runny nose at home:

Try grooming their fur - sometimes brushing can release any allergen particles they may have picked up on their travels.

Dusting and sweeping can also help remove dust or outdoor debris that may be bothering their nasal passages.

Running a humidifier in your home can also help with congestion and make breathing more comfortable. 

When to worry:

If your cat has facial swelling, sudden difficulty breathing, or thick colored discharge coming out of their nose, it’s time to visit the emergency vet. Any sign that your cat isn’t breathing normally should always be taken seriously.  

Symptom 6: Behavioral changes in your cat

Is your cat acting a bit “off?” If your normally charming chaser-of-toys suddenly seems too pooped to party, it could point to allergies - sometimes the earliest signs show up as subtle behavioral shifts. Pay attention if your cat shows behavioral issues.

Some allergy behaviors of cats include:

• Hiding more than usual

• Irritable or restless 

• Avoiding certain foods or environments

• Licking, chewing, or scratching one area repeatedly

How to help your cat's behavior at home:

Sometimes stress can cause behavioral shifts. Try to establish a predictable routine for your kitty filled with positive attention, playtime, and safe, quiet places to rest. You can also try new cat litter or scratching posts. 

When to worry:

If behavioral changes happen suddenly - especially alongside swelling, vomiting, or trouble breathing - don’t wait. Behavioral distress can be one of the earliest clues that a reaction is escalating. 

Symptom 7: Cat with respiratory issues: coughing, wheezing, or breathing changes

Coughing, wheezing, and sneezing are more than just cartoon-like behaviors in your cat - they’re legitimate signs of respiratory discomfort. Sometimes mistaken for a cold, allergies can impede your cat’s airways and impact his ability to breathe. And if left untreated, a so-called harmless little allergy can escalate and cause further complications.

How to help your cat's breathing at home:

The truth is, you can't. Breathing changes are almost always cause for concern. There’s not much you can do at home besides make them comfortable; seek ER veterinary care.

When to worry:

It’s important to take your cat’s wheezing and other respiratory symptoms seriously. These symptoms can progress quickly, and fast treatment greatly improves outcomes. Seek emergency veterinary care immediately if you notice:

• Open-mouth breathing

• Wheezing or repeated coughing

• Rapid or labored breathing

• Pale or bluish gums

How emergency vets treat allergic reactions 

Knowing what to do for a sick pet is always a scary situation. Fast treatment can reverse most allergic reactions, but delaying care can be dangerous - luckily, our 24/7 VEG emergency veterinarians will be there with you from start to finish, making sure your kitty is in the best hands and getting the best care possible. Here’s what you might expect from an emergency vet visit for cat allergies.

Treatment our vet may take for cat allergies

• Assess breathing and heart function.

• Provide oxygen therapy if needed. 

• Administer fast-acting medications like antihistamines or steroids. 

• Start IV fluids for support.

• Treat swelling, hives, or gastrointestinal symptoms.

• Monitor your cat to make sure symptoms don’t return. 

Visit VEG 24/7 emergency vet hospital if your cat has allergies

Allergies can escalate fast — especially when breathing or swelling is involved. If your cat is showing any worrying symptoms, visit your nearest VEG location. Our team is always here, day and night, to help your cat feel better as quickly as possible.

At VEG, we’re committed to providing immediate care to help manage your cat's allergies and ensure his well-being. Your fast response can make a significant difference in your cat's health!