Food Allergy

Food allergy is commonly associated with auricular disease both in dogs and cats (see Chapter 6). The pathogenesis of cutaneous nontoxic adverse reaction to food can involve immune-mediated or non-immune-mediated mechanisms.

In cats, facial pruritus is probably the most common presentation of food allergy. Excoriations caused by the intense self-mutilation are usually not restricted to the pinna but also affect the preauricular area, face, and neck. As opposed to canine cases of food allergy, otitis externa is rare in cats.

In one study of 51 food-allergic dogs, Rosser⁸ stated that 80% of cases had otitis externa and that it was the only symptom in 20%. Pinnal lesions mainly result from otitis externa-related pruritus (Figure 12-5). Improvements in pruritus and skin lesions during the food trial may not be obvious if the perpetuating factors of the otitis externa are not treated initially (bacteria or yeast proliferation, inflammation associated ear canal or pinna changes).