Canine Allergies 101 - Environmental

Environmental allergies are also known as atopy.

This can be allergies to pollens, mold, other animals, plants, housedust, etc. It can be seasonal or year round. Classic skin lesions are on the abdomen, inner thighs and armpits. The gold standard for diagnosis is skin testing, but some labs have fairly accurate blood tests. (Sidenote - several labs advertise blood tests for food allergies but I recommend checking with a dermatologist first.)

Treatments include avoidance of allergens when possible, or antihistamines. Steroids are often used, but merely mask symptoms by suppressing the immune system, and have a whole slew of other nasty side effects. I use them only for the short term and as a last resort.

Cyclosporine is a new treatment that selectively suppresses the allergy portion of the immune system. It's supposed to be extremely effective, and very safe - but pretty costly for big dogs. As for antihistamines - Benadryl is effective in some dogs, but my experience has been that is not quite 50%. For any antihistamine, I recommend a two-week trial at the high end dose and frequency. If we see improvement, then you start decreasing the frequency and amount to get to the lowest effective dose. If we don't see any improvement in two weeks, then that particular antihistamine is unlikely to help, so you try a different one. Just like people, dogs have different responses to different drugs, so what might work for one may not work for another.

Also see Canine Allergies 101