Environmental allergens (such as ragweed, pollens, grasses, trees, molds, etc) have long been suspected as being a major factor in flare - ups of canine
seasonal allergic dermatitis (known as atopy).
The
seasonal effects of allergies to inhalants and ectoparasites such as fleas, followed by the onset of skin and coat disorders including pyoderma,
allergic dermatitis, alopecia, and intense itching, have also been linked to changes in behavior.