Helpful hints for the successful treatment of canine atopy - DVM
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Helpful hints for the successful treatment of canine atopy
These practice pearls may help alleviate some of the itch of this irritating condition in your veterinary patients.


Nutritional measures

There is evidence to show that the proper diet may help relieve clinical signs of atopy.4 Flaxseed oil and fish oil are both rich in omega-3 fatty acids. For flaxseed oil to have anti-inflammatory effects comparable to fish oil, it must be converted to eicosapentaenoic acid (EPA). Unfortunately, conversion in dogs is only about 10 percent, so fish oil is a better source of omega-3 fatty acids in dogs.

Diets rich in essential fatty acids (EFAs) may provide higher amounts of fatty acids than are available via capsules. The best time to start an atopic patient on a diet containing EFAs would be two to three months before its allergic season since it can take two months of EFA supplementation before results are seen. In a study of 50 atopic dogs fed one of four diets over an eight-week period, the dogs fed a fish-based diet had a much lower pruritus score.4

It is now known that reactions to food ingredients can mirror the clinical signs of atopy. There appears to be cross reactivity between foods and inhalants, with grasses cross-reacting with grains as an example. It may be a good idea to start a therapeutic hypoallergenic diet in atopic dogs one to two months before their affected season. There are currently no over-the-counter hypoallergenic diets, despite some food manufacturers "alluding" to such. A study examining four over-the-counter foods labeled as venison-only contained soy, poultry and/or beef protein in the formulation, and these were not listed on the label.5 So it is important to use a therapeutic, veterinary-distributed hypoallergenic diet in treating or testing for food allergy. It appears that with therapeutic hypoallergenic diets, the ingredients are more or less guaranteed to be what the label states.

Secondary factors

Because of the defective skin barrier present in atopy, which doesn't allow the normal bacterial flora (or yeast) to be kept in check, it is important to address the secondary bacterial or yeast component in atopic patients. Using antibiotics, antiyeast medications or antibacterial-antiyeast shampoos can help alleviate clinical signs. Miconazole formerly considered in yeast-fungal infections has now been found to have antibacterial properties.6

Contact time with shampoos should be a good 10 to 15 minutes. Most antibacterial-antifungal shampoos do not lather well, so owners do not feel they're effective. Tell owners not to keep using more product to generate a lather; it will never happen. And be sure to ask the owner about the patient's response to shampoos since not every dog with yeast responds to antiyeast shampoos, and some may actually be irritating. We don't want to make the dog worse with bathing.

I usually start with a hypoallergenic shampoo just as a cleansing shampoo and have clients spot-test the more medicated shampoos to be sure no adverse reactions occur. Stripping shampoos such as those that are tar-based are rarely needed in atopic patients.

If systemic antibiotics are used, be sure to treat long enough and without corticosteroids if possible. Sometimes even a tiny dose of systemic corticosteroid will compromise the full potential of the antibiotic. Topical corticosteroids are favored over systemic corticosteroids. Low-potency topical corticosteroids are preferred over long-acting sprays, which most owners tend to overuse. Oral antifungals such as ketoconazole or fluconazole can help control the secondary yeast overgrowth and can usually be reduced to two times a week as a maintenance.

Immunotherapy pointers

If you are using immunotherapy, either injectable or sublingual, remember that flare-ups are not unusual. Owners must be made aware of this as they often have high expectations that the immunotherapy will take care of everything.

Sublingual immunotherapy for atopic dogs has recently become available. It has a similar success rate to injectable immunotherapy (60 percent to 75 percent) and offers advantages in that it is available as oral drops, can be effective in three to six months, does not need refrigeration, and anaphylaxis is not commonly seen (it is reported in 1 percent or fewer of injectable immunotherapy patients).7

My clinic has been using sublingual immunotherapy in patients for more than a year with good results. But as with any type of immunotherapy, nothing is "cookie cutter." Individual patients will vary with their response, ranging from the initial vial being too strong (causing more pruritus) to some patients being maintained on the lower-strength vials and not having to proceed according to schedule.

Just keep in mind that once immunotherapy is dispensed, individual monitoring is essential, and the owner should be checking in routinely or notifying you of any increase in pruritus or flare-up of otitis or bacterial pyoderma. Clients often mention to me that immunotherapy solutions are dispensed to them without any follow-up or reactions to watch for. Even though instructions are available with the immunotherapy, it is essential for you or a member of your staff to sit down and go over instructions—what to watch for and how often or when to contact your office.


Source: DVM360 MAGAZINE,
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