This guide discusses how allergies can affect your cat, with a focus on the different ways you can help with the management of these often complicated conditions.
What is an allergy?
An allergy is – an overreaction by your cat’s immune system to an allergen, resulting in the over production of antibodies and ultimately the occurrence of symptoms (e.g. a food allergy or hay fever).
An allergen is – a normally harmless substance which causes the immune system of allergic cats to produce an abnormal response (e.g. chicken or a type of grass pollen).
Some cats may tolerate exposure to many allergens and not show symptoms. However, there is usually a limit which when reached, will cause symptoms to be displayed. This is called the ‘allergy threshold’.
The allergy threshold
One way to explain the allergy threshold is by imagining your cat as an empty glass and all the things they are allergic to (allergens) as different liquids.
This doesn’t cause any problems until you reach the brim of the glass, the ‘threshold’; if you continue adding liquid at this point, then the glass will overflow.
In the same way, if your cat is exposed to lots of allergens, or too much of any one in particular, they ‘spill over’ the threshold and you see symptoms associated with allergy such as itching, tummy upsets or coughing.
How quickly this threshold is reached will vary between cats. For some, one single allergen, perhaps exposure to dandelions or dust mites, may be enough to push that particular cat over its threshold. For another cat, it may be the cumulative effect of multiple allergens that results in symptoms occurring.
Identifying which allergens affect your cat is imperative, in order to be able to reduce the contact it has with them. This will help keep your cat as far under its individual threshold as possible and help to decrease symptoms and reduce the risk of flare ups. It is also important to understand that cats with allergies will always be prone to flare ups, as they will be closer to the threshold than a cat without them.
Symptoms of Allergy
There are several different symptoms displayed by cats suffering from allergy, these include:
Itching, skin lesions, hair loss / over grooming
Increased frequency of defecation, softer stools or diarrhoea, weight loss, vomiting
Wheezing, coughing (may be mistaken for hairballs), increased breathing effort/rate
Ruling-out other causes first
A cat with skin symptoms could have an allergy to food, fleas, to something in their environment or to all of these together! Alternatively, their symptoms could be caused by an entirely different problem as many conditions look exactly the same on the outside. This is why it’s really important to rule-out other common reasons for skin problems first, including infections (bacterial and fungal) and ectoparasites (fleas, mites and lice).
Likewise, cats with digestive signs may require blood tests and/or stool analysis first, or cats with respiratory symptoms may need blood tests and x-rays, to help rule-out other common reasons for both of these signs.
How do I find out if my cat has a food allergy?
A cat with a food allergy may display skin symptoms, digestive symptoms or both. Food allergies are common, especially in cats with skin problems. The only way to diagnose a food allergy is by conducting a food trial and this in itself should be seen as a diagnostic test.
A food trial entails feeding a very strict diet for 8-12 weeks, or until the symptoms have significantly improved. If the symptoms do improve, the original diet is given again. Only if symptoms return after re-feeding the original diet can the diagnosis of a food allergy be made (to ensure the improvement wasn’t caused by something else).
A food trial must be run properly in order for the results to be useful. There are blood tests available to help select which food to use for the trial.
Ideally, further investigation will then occur to identify which individual ingredients within the food are causing the reaction, so these can then be permanently removed from the diet.
For some cats with food allergies, if you remove the problem foods from their diet their symptoms will completely resolve, preventing the need for life-long medication. Other cats will have both a food allergy and other allergies in addition (usually to things in their environment and/or fleas), so you may only see a partial improvement when the problem foods are removed. This partial improvement is still really beneficial though as it may reduce the amount of medication they need or how often their symptoms flare up.
Identifying and avoiding allergens
After the other common causes of skin and respiratory symptoms (including food allergies for skin signs) have been ruled-out, the diagnosis of an environmental allergy (known as atopic dermatitis) can be made.
Allergy testing can then be used to help identify which allergens are responsible. If appropriate, a specific therapy can then be made, based on just the allergens causing a problem for that individual cat. This is known as Allergen Specific Immunotherapy (ASIT). In addition, there are ways to avoid and limit exposure to the allergens, and other therapies to reduce the symptoms of itching or treat any infections (see later for more details). Often a combination of treatments is required.
Top tips for avoiding allergens
Allergy to grass, weed or tree pollens:
- Keep lawns mown and weed free.
- Keep hedges trimmed to prevent them flowering.
- Regularly groom or wipe over your cat with a damp cloth (if they will tolerate this),
especially after exposure to long grass and/or weeds.
- Encourage your cat to stay indoors when the pollen count is high or grass is being
- Change your clothes after you have been outside to avoid bringing pollens indoors.
- Try not to dry clothes outside – they can catch pollen.
- Keep windows and doors shut as much as possible when the pollen count is high.
- Do not keep fresh flowers in the house.
Allergy to house dust mites or storage mites:
- Storage mites often live in the dusty residue of dried cat food whereas house dust mites can be found in soft fabrics and furnishings within the home – no matter how clean your house is! They are both very common allergens for cats.
- Purchase small bags of cat food to ensure fresher batches are fed and bags are not left open for long periods.
- Store dry food in its original packaging and inside a resealable container. Discard any dust at the bottom of the container first and ensure it is clean and dry. Alternatively, use wet food.
- If they will tolerate it, wipe your cat’s face with a damp cloth when it has finished feeding to remove food residues.
- Avoid excess cushions and throws on the furniture.
- Avoid a build-up of dust in the home. Vacuum your carpet and dry-clean your curtains and upholstery regularly.
- Regularly wash your cat’s fabric toys at hot temperatures, or alternatively freeze them for 24 hours and then wash them at a lower setting.
- Don’t allow your cat to sleep in your bedroom, especially on your bed – your pillows, duvet and mattress are a hot spot for dust mites!
Allergy to moulds:
- Keep bathrooms and laundry areas well ventilated.
- Treat any damp walls with a mould inhibitor.
- Check food sources for signs of mould or rot, especially on fruit and vegetables.
- Avoid heavy vegetation around or over the house, e.g. ivy & other climbing plants.
- Keep the garden free of fallen leaves and other garden debris.
- Ensure the compost heap is well covered and restrict your cat’s access.
- Keep all cat bedding dry and clean.
Successful Allergy Management
For the best chance of long-term success and to reduce the risk of flare-ups, allergy should be tackled from several different angles.
- Preventing skin infections and parasite infestations – skin allergies
Fleas, mites and lice can all contribute to skin problems so year-round protection and prevention is vital. Early detection and treatment will help the skin to recover sooner.
- Treatments and medications – skin and respiratory allergies
Once diagnosed, most cats will also require regular injections, oral medications or inhalers (for respiratory allergies like asthma), or a combination of these, to control the allergy and help prevent flare-ups. You can discuss with your vet what works best for you and your cat.
- Allergen avoidance measures – skin and respiratory allergies
Avoiding the problem allergens, or reducing exposure to them, is often possible. See our handy tips above.
- Repairing the skin barrier – skin allergies
Topical products, foods and oral supplements can all help with this. Many contain ingredients that support the skin barrier and help reduce flare-ups.
- Improve the air quality around your cat – respiratory allergies
Dust, smoke, aerosol products, air fresheners and perfumes can all make your cats respiratory symptoms worse. Using dust free and unscented cat litter may also help.
- Minimising stress – skin and respiratory allergies
Stress can worsen the symptoms of allergies so managing it is important. International Cat Care have some great advice on this at www.icatcare.org/advice/stress-in-cats
Managing allergy is a complicated and multi-faceted process. If you think your cat may have an allergy, contact your veterinary practice to discuss the best way of investigating it further. Allergy is a lifelong condition and there is no ‘quick fix’. However, if diagnosed correctly, your cat’s allergy can be well managed. Your vet will be able to help you decide on what works best for you and your cat.