FELINE ALLERGY
What are allergies and how do they affect cats?
One of the most common conditions affecting cats is allergy. An allergy occurs when the cat's
immune system "overreacts" to foreign substances called allergens or antigens. Those
overreactions are manifested in three ways. The most common is itching of the skin, either
localized (one area) or generalized (all over the cat). Another manifestation involves the
respiratory system and may result in coughing, sneezing, and/or wheezing. Sometimes, there may
be an associated nasal or ocular (eye) discharge. The third manifestation involves the digestive
system, resulting in vomiting or diarrhea.
Are there several types of allergies?
There are four known types of allergies in the cat: contact, flea, food, and inhalant. Each has
common clinical signs and unique characteristics.
Contact Allergy
Contact allergies are the least common of the four types of allergies. They result in a local
reaction to the skin. Examples of contact allergy include reactions to flea collars or to types of
bedding, such as wool. If the cat is allergic to such substances, there will be skin irritation and
itching at the points of contact. Removal of the contact irritant solves the problem. However,
identifying the allergen can be challenging in many cases.
Flea Allergy
Flea allergy is the most common allergy in cats. A normal cat experiences only minor irritation in
response to flea bites, often without any itching. The flea allergic cat, on the other hand, has a
severe, itch-producing reaction when the flea's saliva is deposited in the skin. Just one bite
causes such intense itching that the cat may severely scratch or chew itself, leading to the
removal of large amounts of hair. There will often be open sores or scabs on the skin, causing a
secondary bacterial skin infection. The area most commonly involved is over the rump or base of
the tail. In addition, the cat may have numerous, small scabs around the head and neck. These
scabs are called miliary lesions, a term which was coined because the scabs look like millet seeds.
The most important treatment for flea allergy is to get the cat away from all fleas. Therefore, strict
flea control is the backbone of successful treatment. Unfortunately, this is not always possible in
warm and humid climates, where a new population of fleas can hatch out every 14-21 days.
However, the new topically applied monthly flea products may kill fleas before they have a chance
to bite your cat. When strict flea control is not possible, injections of corticosteroids (or "cortisone"
or "steroids") can be used to block the allergic reaction and give relief. This is often a necessary
part of dealing with flea allergies. Fortunately, cats appear relatively more resistant to the
side-effects of steroids than other species. If a secondary bacterial infection occurs, appropriate
antibiotics must be used.
Inhalant Allergy
The most common type of allergy is the inhalant type, or atopy. Cats may be allergic to all of the
same inhaled allergens that affect us. These include tree pollens (cedar, ash, oak, etc.), grass
pollens (especially Bermuda), weed pollens (ragweed, etc.), molds, mildew, and the house dust
mite. Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens.
However, others are with us all the time, such as molds, mildew, and house dust mites. When
humans inhale these allergens, we express the allergy as a respiratory problem; it is sometimes
called "hayfever." The cat's reaction, however, usually produces severe, generalized itching. In
fact, the most common cause of itching in the cat is inhalant allergy.
Most cats that have an inhalant allergy are allergic to several allergens. If the number is small and
they are the seasonal types, itching may last for just a few weeks at a time during one or two
periods of the year. If the number of allergens is large or they are present year-round, the cat
may itch constantly.
Treatment depends largely on the length of the cat's allergy season. It involves two approaches.
Steroids will dramatically block the allergic reaction in most cases. These may be given orally or
by injection, depending on the circumstances. As stated previously, the side-effects of steroids
are much less common in cats than in people. If steroids are appropriate for your cat, you will be
instructed in their proper use.
Some cats are helped considerably by a hypoallergenic shampoo. It has been demonstrated that
some allergens may be absorbed through the skin. Frequent bathing is thought to reduce the
amount of antigen exposure through this route. In addition to removing surface antigen, bathing
alone will provide some temporary relief from itching and may allow the use of a lower dose of
steroids.
The second major form of allergy treatment is desensitization with specific antigen injections (or
"allergy shots"). Once the specific sources of allergy are identified, very small amounts of the
antigen are injected weekly. This is all in an attempt to reprogram the body's immune system. It is
hoped that as time passes, the immune system will become less reactive to the problem-causing
allergens. If desensitization appears to help the cat, injections will continue for several years. For
most cats, a realistic goal is for the itching to be significantly reduced in severity; in some cats,
itching may completely resolve. Steroids are not used with this treatment protocol, except on an
intermittent basis. This therapeutic approach is recommended for the middle-aged or older cat
that has year round itching caused by inhalant allergy. This approach is not used with food allergy.
Although desensitization is the ideal way to treat inhalant allergy, it does have some drawbacks
and may not be the best choice in certain circumstances.
1. Cost: This is the most expensive form of treatment.
2. Age of Patient: Because many cats develop additional allergies as they get older, young
cats may need to be retested 1-3 years later.
3. Success Rate: About 50% of cats will have an excellent response. About 25% get partial to
good response. About 25% get little or no response. The same statistics are true for people
undergoing desensitization.
4. Food Allergies: Although tests for food allergy are available, the reliability of the test is so
low that it is not recommended at this time. A food trial remains the best diagnostic test for food
allergy.
5. Time of Response: The time until apparent response may be 2-5 months, or longer.
6. Interference of steroids: Cats must not receive oral steroids for two weeks or injectable
steroids for six weeks prior to testing; these drugs will interfere with the test results.
Food Allergy
Cats are not likely to be born with food allergies. More commonly, they develop allergies to food
products they have eaten for a long time. The allergy most frequently develops in response to the
protein component of the food; for example, beef, pork, chicken, or turkey. Food allergy may
produce any of the clinical signs previously discussed, including itching, digestive disorders, and
respiratory distress. We recommend testing for food allergy when the clinical signs have been
present for several months, when the cat has a poor response to steroids, or when a very young
cat itches without other apparent causes of allergy. Testing is done with a special hypoallergenic
diet. Because it takes at least eight weeks for all other food products to get out of the system, the
cat must eat the special diet exclusively for 8-12 weeks (or more). If positive response occurs, you
will be instructed on how to proceed. If the diet is not fed exclusively, it will not be a meaningful
test. We cannot overemphasize this. If any type of table food, treats or vitamins are given, these
must be discontinued during the testing period.
Because cats that are being tested for inhalant allergy generally itch year round, a food allergy
dietary test can be performed while the inhalant test and antigen preparation are occurring.
What are allergies and how do they affect cats?
One of the most common conditions affecting cats is allergy. An allergy occurs when the cat's
immune system "overreacts" to foreign substances called allergens or antigens. Those
overreactions are manifested in three ways. The most common is itching of the skin, either
localized (one area) or generalized (all over the cat). Another manifestation involves the
respiratory system and may result in coughing, sneezing, and/or wheezing. Sometimes, there may
be an associated nasal or ocular (eye) discharge. The third manifestation involves the digestive
system, resulting in vomiting or diarrhea.
Are there several types of allergies?
There are four known types of allergies in the cat: contact, flea, food, and inhalant. Each has
common clinical signs and unique characteristics.
Contact Allergy
Contact allergies are the least common of the four types of allergies. They result in a local
reaction to the skin. Examples of contact allergy include reactions to flea collars or to types of
bedding, such as wool. If the cat is allergic to such substances, there will be skin irritation and
itching at the points of contact. Removal of the contact irritant solves the problem. However,
identifying the allergen can be challenging in many cases.
Flea Allergy
Flea allergy is the most common allergy in cats. A normal cat experiences only minor irritation in
response to flea bites, often without any itching. The flea allergic cat, on the other hand, has a
severe, itch-producing reaction when the flea's saliva is deposited in the skin. Just one bite
causes such intense itching that the cat may severely scratch or chew itself, leading to the
removal of large amounts of hair. There will often be open sores or scabs on the skin, causing a
secondary bacterial skin infection. The area most commonly involved is over the rump or base of
the tail. In addition, the cat may have numerous, small scabs around the head and neck. These
scabs are called miliary lesions, a term which was coined because the scabs look like millet seeds.
The most important treatment for flea allergy is to get the cat away from all fleas. Therefore, strict
flea control is the backbone of successful treatment. Unfortunately, this is not always possible in
warm and humid climates, where a new population of fleas can hatch out every 14-21 days.
However, the new topically applied monthly flea products may kill fleas before they have a chance
to bite your cat. When strict flea control is not possible, injections of corticosteroids (or "cortisone"
or "steroids") can be used to block the allergic reaction and give relief. This is often a necessary
part of dealing with flea allergies. Fortunately, cats appear relatively more resistant to the
side-effects of steroids than other species. If a secondary bacterial infection occurs, appropriate
antibiotics must be used.
Inhalant Allergy
The most common type of allergy is the inhalant type, or atopy. Cats may be allergic to all of the
same inhaled allergens that affect us. These include tree pollens (cedar, ash, oak, etc.), grass
pollens (especially Bermuda), weed pollens (ragweed, etc.), molds, mildew, and the house dust
mite. Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens.
However, others are with us all the time, such as molds, mildew, and house dust mites. When
humans inhale these allergens, we express the allergy as a respiratory problem; it is sometimes
called "hayfever." The cat's reaction, however, usually produces severe, generalized itching. In
fact, the most common cause of itching in the cat is inhalant allergy.
Most cats that have an inhalant allergy are allergic to several allergens. If the number is small and
they are the seasonal types, itching may last for just a few weeks at a time during one or two
periods of the year. If the number of allergens is large or they are present year-round, the cat
may itch constantly.
Treatment depends largely on the length of the cat's allergy season. It involves two approaches.
Steroids will dramatically block the allergic reaction in most cases. These may be given orally or
by injection, depending on the circumstances. As stated previously, the side-effects of steroids
are much less common in cats than in people. If steroids are appropriate for your cat, you will be
instructed in their proper use.
Some cats are helped considerably by a hypoallergenic shampoo. It has been demonstrated that
some allergens may be absorbed through the skin. Frequent bathing is thought to reduce the
amount of antigen exposure through this route. In addition to removing surface antigen, bathing
alone will provide some temporary relief from itching and may allow the use of a lower dose of
steroids.
The second major form of allergy treatment is desensitization with specific antigen injections (or
"allergy shots"). Once the specific sources of allergy are identified, very small amounts of the
antigen are injected weekly. This is all in an attempt to reprogram the body's immune system. It is
hoped that as time passes, the immune system will become less reactive to the problem-causing
allergens. If desensitization appears to help the cat, injections will continue for several years. For
most cats, a realistic goal is for the itching to be significantly reduced in severity; in some cats,
itching may completely resolve. Steroids are not used with this treatment protocol, except on an
intermittent basis. This therapeutic approach is recommended for the middle-aged or older cat
that has year round itching caused by inhalant allergy. This approach is not used with food allergy.
Although desensitization is the ideal way to treat inhalant allergy, it does have some drawbacks
and may not be the best choice in certain circumstances.
1. Cost: This is the most expensive form of treatment.
2. Age of Patient: Because many cats develop additional allergies as they get older, young
cats may need to be retested 1-3 years later.
3. Success Rate: About 50% of cats will have an excellent response. About 25% get partial to
good response. About 25% get little or no response. The same statistics are true for people
undergoing desensitization.
4. Food Allergies: Although tests for food allergy are available, the reliability of the test is so
low that it is not recommended at this time. A food trial remains the best diagnostic test for food
allergy.
5. Time of Response: The time until apparent response may be 2-5 months, or longer.
6. Interference of steroids: Cats must not receive oral steroids for two weeks or injectable
steroids for six weeks prior to testing; these drugs will interfere with the test results.
Food Allergy
Cats are not likely to be born with food allergies. More commonly, they develop allergies to food
products they have eaten for a long time. The allergy most frequently develops in response to the
protein component of the food; for example, beef, pork, chicken, or turkey. Food allergy may
produce any of the clinical signs previously discussed, including itching, digestive disorders, and
respiratory distress. We recommend testing for food allergy when the clinical signs have been
present for several months, when the cat has a poor response to steroids, or when a very young
cat itches without other apparent causes of allergy. Testing is done with a special hypoallergenic
diet. Because it takes at least eight weeks for all other food products to get out of the system, the
cat must eat the special diet exclusively for 8-12 weeks (or more). If positive response occurs, you
will be instructed on how to proceed. If the diet is not fed exclusively, it will not be a meaningful
test. We cannot overemphasize this. If any type of table food, treats or vitamins are given, these
must be discontinued during the testing period.
Because cats that are being tested for inhalant allergy generally itch year round, a food allergy
dietary test can be performed while the inhalant test and antigen preparation are occurring.
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Animal Hospital of Fate Rockwall, Texas 75087 972-722-0066 |
| (Highway 66 in Fate) Rockwall, Texas 75087 972-722-0066 |