Steroids such as prednisone, methyl prednisolone and trimacinolone bring relief to allergic dogs by decreasing inflammation. At higher doses, they actually suppress the immune system. Unfortunately, they also have many unwanted side effects because they effect so many body systems. Dogs on steroids often have increased thirst, appetite and urinations. They may also suffer with excessive panting, vomiting, diarrhea, gastrointestinal ulcers, pancreatitis, muscle wasting and liver problems.
When I was in high school, I remember taking our dog in for an allergy shot. The shot was actually a long–acting glucocorticoid (steroid) called triamcinolone. Although this treatment brought him relief, I later learned it also has many dangerous side effects. Early in my career, I saw a yellow lab who suffered from liver disease. Her gums, eyes and other mucous membranes were actually yellow in color from bilirubin. The dog had been on triamcinolone injections for most of her life to control her allergies. Now at only 8 years of age, her liver failed. Despite aggressive treatment, she did not survive.
Because of the side effects, I reserve steroid therapy for dogs with severe cases of allergies and allergies that are not responding to other treatments. For these dogs, I prefer using a drug called Termaril P that is a combination of the antihistamine trimeprazine and prednisone. This drug comes in a pill form. The oral dosing gives better options if side effects should develop. With an injection, once it’s in the body, that’s it. My goal in therapy is to control the dog’s allergies and then get them off as quickly as possible. That usually means the dog will be on the drug for about two weeks, starting with a higher dose for about 3 days and then tapering off. As a brief but important side note, tapering is critical. Animals should not stop steroid treatment without a taper.
Because intradermal or serum allergy testing and desensitization therapy are all expensive, some owners want to use steroids as a cheap alternative. Because of the potential side effects, I strongly discourage this approach. I think the risks associated with chronic steroid therapy far outweigh the benefit. In my opinion, the best treatment is to remove whatever is causing the allergy from the dog’s environment. If that is impossible, then pursue desensitization therapy. As I said before, steroids should be the last resort because of their side effects. Used properly, they are an excellent tool in a veterinarian’s arsenal but again, only in skilled hands after careful consideration.