You may be thinking, “A steroid for my dog’s allergies?”
Is it really necessary?
Is my dog going to look like a bodybuilder?!
Many patients in my clinic have questions about common dog allergy medicines and how they work.
Here is a primer on common dog allergy medicines I prescribe for the toughest conditions.
Corticosteroids have long been a standard therapy for allergies in dogs.
Corticosteroids work primarily by gene repression, which prevents the activation of many immune cells involved in the allergic response.
Despite common use, there are relatively few controlled studies evaluating the efficacy of corticosteroids in the treatment of canine allergies.
When using corticosteroids for treatment of allergies, I generally recommend using prednisone at .5 mg/lb once daily for 7 days, then 0.25 mg/lb once daily for 7 days, then 0.25 mg/lb every other day.
The acute side effects of corticosteroids are well known and include frequent drinking, increased urination, ravenous appetite, and excessive panting.
Chronic use of corticosteroids can lead to iatrogenic Cushing’s disease, pancreatitis, gastrointestinal ulceration, opportunistic infections (especially UTI), obesity, and musculoskeletal problems (muscle wasting).
Dogs should be treated with the lowest effective dose necessary to control symptoms.
Concurrent use of antihistamines and topical therapy may have a “steroid-sparing” effect.
When chronic use is necessary, owners should be advised that every other day administration is always safer than daily dosing.
There is no pharmacologic advantage to using injectable corticosteroids over oral preparations.
Due to the increased likelihood of adverse effects, the use of injectable, long-acting corticosteroid formulations is not recommended for the treatment of canine allergies symptoms.
Allergen-specific Immunotherapy (ASIT)
Allergen-specific immunotherapy (ASIT) is a safe and effective nonsteroidal therapy for dogs with atopic dermatitis.
Most studies indicate that 65-70% of patients show significant (>50%) improvement with immunotherapy.
When possible, intradermal testing should be utilized in order to formulate ASIT.
It is important for owners to realize that ASIT is a chronic therapy for atopy, and it may take 3-6 months or longer to see a significant reduction in symptoms.
In order for immunotherapy to be effective, control of secondary infections and concurrent allergies is critical.
In addition, frequent follow-up (by phone or in person) is necessary.
A recent study has shown that immunotherapy is most successful in dogs whose owners have frequent contact with their dermatologist.
A textbook approach to immunotherapy is less likely to be effective.
Cyclosporine (Atopica) is an immunosuppressive drug originally developed to prevent human organ transplant rejection.
Modified cyclosporine (CsA)
Modified cyclosporine (CsA) was developed to have more reliable absorption and greater bioavailability following oral dosing.
CsA has been used in the management of human atopic dermatitis, and recent studies have demonstrated that CsA is an effective therapy for canine atopic dermatitis (AD), as well.
The recommended dose for treatment of canine AD is 5 mg/kg, once daily, using the modified formulation of CsA (Atopica, Novartis).
In some dogs, the dose can be reduced to every other day after 4-8 weeks.
With chronic use, twice weekly dosing may be effective for some patients.
The most common side effects include vomiting and diarrhea.
These side effects are usually transient and resolve spontaneously within a few days.
Cutaneous flushing, excessive panting, hepatotoxicity, renal changes, gingival hyperplasia, muscle tremors, and secondary infections have all been reported on rare occasions.
People taking CsA for long periods of time have occasionally developed malignancies.
While this has not been reported in the dog, CsA should not be used in dogs with a history of malignancy.
I recommend doing a CBC and serum chemistry panel prior to and 30 days after initiating therapy.
If no abnormalities are seen, repeating these tests every 3-6 months may be prudent.
Urinalysis and/or urine cultures should be done 1-2 times yearly to monitor for bacterial cystitis.
Which drugs have you tried for your pup’s allergies?
Which have been successful?