Allergies 101

What are allergies, and how do they affect pets?
One of the most common conditions affecting dogs and cats are allergies. In the allergic state, the dog's immune system “overreacts” to foreign substances (allergens or antigens) to which it is exposed. These overreactions are manifested in three ways. The most common is itching of the skin, either localized (one area) or generalized (all over). 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 five known types of allergies in dogs and cats: contact, flea, food, bacterial, and inhalant. Each of these has some common expressions, and each has some unique features.

CONTACT ALLERGY
Contact allergy is the least common of the five types of allergy. They result in a local reaction of the skin. Examples of contact allergy include reactions to flea collars or to types of bedding, such as wool. If the pet 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 require some detective work.

FLEA ALLERGY
Flea allergy is common in dogs and cats. A normal animal experiences only minor irritation in response to flea bites, often without any itching. On the other hand, the flea allergic animal has a severe, itch-producing reaction when the flea's saliva is deposited in the skin. Just a few bites cause such intense itching that the dog or 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, allowing a secondary bacterial infection to begin. The area most commonly involved is over the rump (just in front of the tail).
The most important treatment for flea allergy is to get the animal 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. When strict flea control is not possible, 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. If a secondary bacterial infection occurs, appropriate antibiotics must be used.
There are many over the counter products but they are usually ineffective and can be dangerous to humans and animals, especially cats. We have seen pets get very ill from some over the counter products. We can help pick a product tht will work well and be safe for your pet

BACTERIAL ALLERGY
There are many types of Staphylococcus (Staph) bacteria. Some cause severe disease and some do not. There are several species of Staphylococcus bacteria that live on normal dog skin. If the skin is normal and the dog's immune system is normal, Staph causes no problems to its host. However, some dogs develop an allergy to this bacterium. When this happens, the dog develops areas of hair loss that look much like ringworm. They are often round and 1/2 to 2 inches (1-5 cm) in diameter These same lesions develop in true Staph infection; they are easily treated with certain antibiotics, but the Staph-allergic dog has recurrent “Staph infections.” The lesions will usually clear with appropriate antibiotics but return as soon as antibiotics are discontinued. After a while, some dogs become resistant to antibiotic treatment.
Treatment of Staph allergy involves antibiotics to control the immediate problem and desensitization with Staph antigen for long-term relief.
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INHALANT ALLERGY
The most common type of allergy is the inhalant type, or atopy. Dogs may be allergic to all of the same inhaled allergens that affect humans. 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 “hay fever.” The dog's reaction, however, usually produces severe, generalized itching. In fact, the most common cause of itching in the dog is inhalant allergy.
Most dogs that have inhalant allergies react to several allergens. If the number is small and they are the seasonal type, 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 dog may itch constantly.
Treatment depends largely on the length of the animal's allergy season. A treatment plan will be developed for you and your pet because every animal responds differently and has different needs.
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FOOD ALLERGY
Dogs and 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 pet has a poor response to steroids, or when a very young dog 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 ystem, the pet 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. We have treats that are hypoallergenic and made for animals with food allergies. There may be problems with certain types of chewable heartworm preventative, as well. We can discuss the options with you.

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