Atopy is an allergic reaction to an allergen that is inhaled or absorbed through the skin. Most allergies are this type and many are seasonal — at least initially. Over time, these often become year-round allergies. The most common allergens are mold and mildew; grass, tree, and weed pollens; and dust mites and dander. Offending grasses include the following:

• Bluegrass

• Fescue

• Orchard grass

• Redtop/brome grass

• Ryegrass

• Timothy

The weeds that cause the most allergic reactions in dogs include the following:

• Cocklebur

• Dock

• Firebush

• Goldenrod

• Pigweed

• Plantain

• Ragweed

• Russian thistle

• Sage

The following trees are responsible for many inhalant allergies:

• Alder

• Ash

• Birch

• Box elder

• Cottonwood

• Hazelnut

• Hickory

• Juniper

• Mulberry

• Oak mix

• Red maple

• Sycamore

• Walnut

• Willow

When a dog has been exposed to a seasonal allergy, he will chew and scratch only during the time the allergens are prominent. This kind of allergy is easier for the veterinarian to treat than a year-round allergy problem. If she is going to use medication to treat an inhalant seasonal allergy, less medication is needed and the allergen is usually gone by the time the symptoms have disappeared. This treatment will usually be required the following year when the allergen is in season again.

Treating Atopy

To diagnose atopy, the holistic veterinarian may use a blood test to screen for antibodies for common allergens. Two standard blood tests veterinarians use are the ELISA (enzyme-linked immunoabsorbent assay) and the RAST (radioallergosorbent test). Both can produce false positives and false negatives, although more veterinarians rely on the accuracy of the ELISA test.

Intradermal skin testing is considered the gold standard for identifying the allergens that cause atopy because of its accuracy, but it is more invasive. The dog must be sedated and multiple antigens are injected into the dog's skin. Allergic reactions will cause raised red areas. The veterinarian identifies the problem allergens and mixes a small amount of those allergens to create injections for your dog. These allergens will be injected on a specific schedule and will gradually be increased in strength over time. You will often be referred to a veterinary dermatologist for this therapy.

Using natural anti-inflammatory drugs along with fatty acid supplements is another form of allergy treatment. Antihistamines might be effective in controlling allergies as well. When used with other therapies including fatty acids and avoidance techniques, antihistamines can reduce allergic reactions. However, histamine is not the primary cause of allergic inflammation in dogs, so antihistamines have variable results in our itchy canines. About 40 percent of dogs will respond to one of the antihistamines. Therefore, it is commonly recommended that antihistamines be tried one at a time for about two weeks each to see which is most effective. The typical medications used are Benadryl, Tavist, Chlor-trimeton, and Atarax. Because these drugs have side effects, such as drowsiness, careful dosing is essential. It is important to discuss their use with your veterinarian before trying them.

Many conventional veterinarians will use steroids (such as cortisone, prednisone, dexamethasone, and hydrocortisone) to treat an allergic reaction. Antihistamines and steroids in combination can improve a severe allergic reaction, although many holistic veterinarians are typically reluctant to resort to using steroids if alternative therapies exist. Steroids have serious side effects if used in excess.

Avoiding Allergies

Avoiding offending agents along with other treatments will help manage atopy. First, determine what the allergens are through intradermal skin testing. If your dog is allergic to house dust, vacuum rooms with a HEPA filter vacuum. HEPA filters provide a higher filtration of smaller particles than traditional vacuum cleaner filters and are capable of catching particles invisible to the naked eye. Keep your dog out of the rooms you are vacuuming for a few hours.

Wash your dog's bedding in very hot water and don't let your dog sleep on upholstered furniture, which collects dust and dander. Don't give him stuffed toys, which also fill with dust. Try to keep your dog in rooms that don't have carpeting.

To avoid contact with molds, keep your dog out of dark, airless rooms such as basements and restrict access to the yard when the grass is mowed. Use a portable humidifier in your home and clean and disinfect it regularly. If pollen bothers your dog, keep him out of fields and make sure he stays indoors as much as possible during periods of high pollen counts. After an outing in high grass and weeds, give him a bath or at least rinse him off.

Hyposensitization

Another form of allergy treatment is hyposensitization, or specific antigen injections. Holistic veterinarians have different opinions about whether to use these to provide allergy relief in dogs. When symptoms persist despite your best efforts to avoid allergens and to control allergies with appropriate drug and supplement use, many holistic vets will recommend hyposensitization. These allergy shots use the dog's own body to find a solution. Unfortunately, this therapy is very expensive and dogs need to be retested once a year to once every three years because many problems recur.

After intradermal skin testing has identified offending allergens, very small amounts of an antigen are injected once a week. This reprograms the body's immune system to accept the allergen. The goal is to eventually program the immune system not to react to the allergen at all.

If these injections are helpful, the dog will need to have them for several years — sometimes for the rest of his life. There is a 50 to 80 percent success rate with this therapy. However, this does not guarantee complete resolution of the problem — only improvement. Hyposensitization is usually suggested for the adult dog with year-round atopy or for dogs that have an unsatisfactory response to medical treatment.