by ANDREW M. STREIBER, DVM

Q:  My dog’s allergies seems to flare up and cause him to itch more in the fall, than during the spring and summer months.  What might explain this?

A:  It’s logical to assume that spring and summer would be the most troublesome seasons of the year for any animal (humans included!) previously diagnosed with allergies.  Over time however, I have come to think otherwise.

The seasonal rise in allergic dermatitis in our pets can be attributed to several factors, and may vary depending on climate.  Here in Southern California, warm Santa Ana winds start blowing, carrying allergens with them.  Fall foliages such as grasses, trees, plants and flowers start to bloom, bringing various pollens and aerosolized inhalants.

In colder regions, home furnaces are back in use and may stir up dust or anything else that has collected in the ducts during the off season.  The addition of particles to the air we breath likely acts on our animals and the allergens with which they already live.

Though environmental factors might go a long way to answer your question, a safe approach to this issue does not vary from season to season.  In dogs, we must always begin by ruling out hypothyroidism, dietary issues and ectoparasites as the cause of allergic dermatitis before we may rule atopy — allergies to the environment — in.