Cat allergies are estimated to affect up to 20% of the entire worldwide population – and cats themselves are a common cause of allergies, meaning they frequently trigger allergic reactions in sensitive individuals.

So, why are some people allergic to cats and others aren’t? And what can you do to manage your symptoms when they start to appear?

In this article, we answer both of these questions and more, so keep reading to find out. 

What causes a cat allergy?

Cat and dog hair are the most common types of animal allergens and can cause year-round symptoms. However, while many people believe that it’s a cat’s fur that causes allergic reactions, this isn’t necessarily true.

Having an allergic reaction to a cat is actually triggered by specific proteins found in the animal’s dander (flakes of skin), sweat, oil, saliva, urine and faeces. In fact, over 90% of people with cat allergies are allergic to proteins found in cat saliva or skin.

When these proteins stick to a cat’s fur, they can easily transfer onto objects like mattresses, carpets, rugs, clothes or soft furniture. They can also become airborne, so you might inhale them or have them land on your skin without even realising.

If you’re allergic to cats, being exposed to these specific allergens may cause you to experience an allergic reaction, bringing with it a whole host of possible symptoms.

What may happen during an allergic reaction?

After recognising your exposure to the cat allergen , your body’s immune system will trigger an allergic reaction against it by releasing antibodies and various chemical substances, including enzymes and mediators (chemical messengers).

One of the main substances that gets released through this process is called histamine . And it’s this chemical that’s responsible for causing many of the symptoms associated with having an allergic reaction, including everything from a runny nose to itchy eyes (but more on those later!).

Can you develop a cat allergy?

It is perfectly (or should that be ‘purrfectly’?) possible to develop an allergy to an animal or pet at any time in your life, even if the pet has been owned for a considerable length of time or where a pet does not live in your home.

While the exact reason behind this remains somewhat unknown, the persistent nature of cat allergens means that even years after a cat has left a home or environment, the residual allergens could still cause an allergic reaction.

That's why, if you have allergies and are in the process of moving home or starting at a new school or workplace, it’s important to find out whether any cats lived there beforehand.

Which symptoms are caused by cat allergies? 

For people with a cat allergy, coming into contact with cat dander, saliva or urine may trigger the onset of what’s known as allergic rhinitis – a condition where your nose gets irritated by something you’re allergic to (in this case, a cat allergen).

According to the NHS, this can lead to symptoms like:

• Sneezing
• Having an itchy, runny or blocked nose
• Itchy, red or watery eyes
• Swollen eyelids
• Feeling weak and tired
• The roof of your mouth becoming itchy

These symptoms usually appear within a matter of minutes of being exposed to the cat allergen. So, while you may not be able to see it with your naked eye, your body’s reaction may indicate when a cat allergen is within your vicinity.

Exposure to animal allergens (such as cat allergens) may also lead to a scratchy throat and, in rarer cases, hives and skin rashes. It’s important to talk to your doctor if you experience any of these symptoms. 

Are there any complications associated with cat allergies?

Being allergic to cats can sometimes cause more problems than the symptoms listed above.

For example, if you have asthma, being around cats might make your symptoms worse. At the same time, if you have a cat allergy and experience allergic rhinitis symptoms, this might make you more likely to develop asthma.

As such, it’s important to talk to your doctor if you think you, or someone you care for, may be allergic to cats or have a family history of atopy (a genetic tendency to develop allergic diseases like allergic rhinitis), as this could leave you at an increased risk.

Certain other complications can be associated with allergic rhinitis as well, including nasal polyps, sinusitis , middle ear blockage and sleep disturbances. However, these can all usually be treated using medication. Surgery may also be required in some cases, but typically only if your symptoms are severe or have occurred over a long-term period.

How to manage a cat allergy: treatment and prevention

So now we know why cat allergies occur, what can you do to help manage your symptoms when you next experience an allergic reaction?

Fortunately, there are several ways to help prevent or alleviate symptoms of an allergic reaction. For example, here’s what bodies like the NHS, NICE and Allergy UK advise you should do:

• Avoid visiting any homes or areas where cats live
• Groom your cats regularly and, if required, speak to your vet about how to wash them
• Regularly wash your cat’s bedding and clean any furniture they've been on
• If you have cats yourself, keep them outside if possible and always out of the bedroom
• Use hypoallergenic bedding and covers
• Wash your bedding regularly at 60°C or higher
• Dust around your home with a damp cloth
• Regularly use a vacuum with a high-efficiency particulate air ( HEPA ) filter
• Keep your home dry and well-ventilated using an air purifier
• Wash your hands after touching or being licked by a cat

Make sure to take a look at Allergy UK’s animal allergy factsheet and the NHS’s dedicated allergic rhinitis page for further advice and support.  

Will I need to rehome my cat?

If you develop an allergy to a cat you already own, you don’t need to rush to rehome them.

By implementing some of the prevention methods above and seeking advice from your doctor, it may be possible to manage the situation. However, this will depend on the severity of your symptoms and the treatment options available to you, as recommended by your doctor.

Rehoming your cat may also not offer immediate symptom relief, as cat allergens can be very stubborn (just like their feline carriers can be!) and actually remain in dust around the house for up to six months.

How to treat a cat allergy

When managing the symptoms of allergic rhinitis (triggered by a cat allergy), there are several over-the-counter medicines you can take to help. These typically include:

• Antihistamines: block the effect of histamine, which causes allergy symptoms
• Decongestant nasal sprays or drops: help clear your blocked nose
• Saltwater nasal sprays or solutions: can be used to rinse out your nasal passages
• Inhaled steroids (corticosteroids): help reduce inflammation and various allergy symptoms

You can find these treatments at your local pharmacy or wherever you get your groceries. They’re also generally available in a wide variety of forms and designed to relieve allergy symptoms caused by a number of the most common allergens, including cats.

For example, Clarityn® Allergy Tablets offer a prescription-strength form of antihistamine that provides 24-hour allergy relief from symptoms caused by over 150 airborne allergens, such as pet dander.

Meanwhile, Clarinaze® Allergy Control Nasal Spray is designed to provide prescription-strength relief from the nasal symptoms associated with allergic rhinitis, including nasal congestion, sneezing and a runny nose.

However, if you find that these treatments don’t improve your symptoms or they start to get worse, talk to your doctor. They may recommend a different type of medicine or refer you to a specialist for further evaluation and treatment.

For more advice on managing cat allergies, take a look at our dedicated guide, where we share seven great hints and tips to help you find relief.