An allergy test is performed in dogs to find out which allergens from the environment your cat reacts to (e.g., house dust mites, moulds, tree, grass, weed, cereal pollen).
What is an allergy?
An allergy, also called a hypersensitivity reaction, denotes an excessive reaction of the immune system to quite normal environmental stimuli. In cats with allergies, the immune system thus not only fights disease germs and harmful substances but also things that are actually not dangerous. Typical cat allergies are to pollen, ingredients in their feed and parasites or their faeces. Chemicals in furniture and textiles can also cause allergies in cats. The concept of “allergy in cats” is not yet completely understood, even after years of intensive research, and it is a very complex disease. (You will find more basic information on allergy here.)
How do I recognise an allergy in a cat?
The symptoms of an allergy are relatively nonspecific and could therefore be caused by other diseases also. Itching, vomiting, diarrhoea or, in the worst case, shortness of breath can be due to an allergy. To provide the animal with optimal help, it must therefore be distinguished from other diseases. To do so, the vet will do various tests and seek answers to the following questions, for example:
- Which organs are diseased?
- Is it perhaps due to an infectious disease?
- How do the symptoms change over time?
- What appeared to trigger the symptoms?
- Have there already been attempts at treatment?
Much of this will give him or her clues about possible causes of the disorder.
By the way: you as the cat's owner are extremely important in looking for the cause. You know what your cat eats, whether he has been given medications and how she behaves normally. All of this can help the veterinary surgeon to identify the allergy. Even getting a new sofa can trigger an allergy in a cat that nobody knew about before.
The diagnosis “allergy” is usually a diagnosis of exclusion, that is, it is the only disease left after everything else has been investigated. An allergy test should be done in an cat only AFTER an allergy has been diagnosed.
How does an allergy test work in cats?
There are two different ways of testing a cat for allergies:
In the skin test (prick test, intradermal test), various antigens (that is, potentially allergenic substances) are injected into the skin and the reaction is observed. The cat's hair is clipped on the side of its chest or belly. 30-50 different test solutions are then injected. The cat is given sedation for this to make it less unpleasant. After about 20 minutes, which substances the skin reacts to with swelling (a wheal) and redness and which it does not react to are noted. The skin test is thus performed directly in the practice and the result is seen immediately.
However, not all veterinary practices provide this: storing the many antigen solutions and performing the test correctly require some effort and are worthwhile only if the test is used often enough.
Serological allergy test
For a serological allergy test, blood is taken from the cat. This is sent to a special laboratory and tested. IgE antibodies in the dog’s blood against, e.g., pollen, moulds, house dust mites, etc. are then sought. (Antibodies normally serve to fight off dangerous influences from without; in an allergy, this reaction is directed against harmless things.)
A test is less suitable for diagnosing food allergies and an exclusion diet is usually the method of choice in this case.
Cat allergy test: is it useful?
Cat allergy tests are performed less for diagnosis of an allergy but rather to find out the substances that are tolerated or that make him or her sick. Seen this way, the name is a bit misleading. The allergy test is not suitable for diagnosing an allergy in itself because even cats without an allergy have positive test results. There are also allergic animals whose test turns out negative. Doing an allergy test first when there are allergic symptoms is thus not useful. Doing an allergy test in a cat makes sense when no other cause can be found for symptoms such as itching. If no parasites, fungi or bacteria were discovered and if metabolic diseases have been ruled out, the vet will consider an allergy as the possible diagnosis and do an allergy test on your cat. If the allergy test is positive, the vet will start appropriate treatment; this can consist of desensitisation therapy (that is, reducing the excessive immune reaction), for example in the case of allergies against house dust mites or insect stings. For food allergies, an elimination diet (leaving out certain foods) is the first choice. By the way, various medications, especially anti-inflammatory drugs, falsify the result of a cat allergy test. They should be stopped beforehand in good time. However, you should on no account do this on your own initiative but wait for your vet’s instructions.
If a particularly severe allergy episode is present or, on the other hand, a seasonal allergy is well in the past, this can influence the allergy test.
Positive cat allergy test: what now?
Has your cat had a positive allergy test? Don’t panic! Your vet will discuss and rank the result jointly with you. What to do next will also be discussed. Apart from the aforementioned desensitisation (cat desensitisation) alternative therapies can help to alleviate the consequences of your cat's allergy. With a food allergy, an elimination diet or exclusion diet is usually indicated: your cat is then given only selected foods for a number of weeks (at least 6-8 weeks). If the symptoms improve, the food components that are well tolerated by the animal are discovered - a genuine relief for animal and human. However, a little patience is needed as it really takes several weeks before a result can be regarded as certain. If the test was negative but your cat has a skin disease, you will find more information here on the topic of “Cat dermatology“.
Cat allergy test: costs
“How much does a cat allergy test cost?“ You should be aware that the costs for a cat allergy test comprise various components. These include the work involved (regulated in the veterinary fee schedule) and the material costs. For a serological test there is also the cost of the test in an outside laboratory. If you would like to know what a cat allergy test costs, please talk to your vet.
Cat allergy test: conclusion
An allergy test is a good tool to help cats with an allergy. It is not suitable for diagnosing an allergy but it optimises the treatment.