Clinically known as atopy, inhalant allergy is a hypersensitivity to environmental allergens manifested through irritation of the skin and ears. Atopy occurs in 10 to 15 percent of the dog population and tends first to occur when the canine is between one to two years old. Feline atopy can occur at any age. It is not uncommon for animals to have atopy in conjunction with other allergies such as food hypersensitivity and flea allergy dermatitis.
Patchy hair loss including bacterial demodex, or ringworm infection, or hormonal diseases such as hypothyroidism and Cushing's disease. These diseases should be ruled out by appropriate testing. Skin biopsy of affected areas shows dysplastic (abnormally shaped) hair follicles which are filled with keratin.
In mildly affected animals, the only sign is the formation of asymptomatic comedones (blackheads) which are dilated hair follicles on the midline of the back. In more severely affected dogs, secondary bacterial infection may develop, causing crusts, pimples, hair loss and itching.
Single to multiple raised, hairless, lobulated white to pale pink skin or sometimes pigmented skin masses which may ooze an oily white material. Masses range in size from ¼” – 1” in diameter.