Diagnostic Workup of Equine Atopic Disease

Diagnosis of atopic dermatitis is based on history, clinical signs, and the exclusion of other differential diagnoses. A seasonal history is often seen initially, particularly with equine atopic disease and insect hypersensitivities. Dermatopathology may not be particularly rewarding in the diagnosis of atopic dermatitis because it is relatively non-specific; but it can rule out other infectious, neoplastic, and autoimmune disorders. Testing for IgE using intradermal testing (IDT) has been investigated extensively in the past decade. It has been utilized for the selection of allergens for allergen-specific immunotherapy (ASIT), rather than as a diagnostic tool, in humans, dogs, cats, horses, and other mammalian species. Although available, there is no accurate in vitro or in vivo test for food allergies. The only accurate way to diagnose an adverse food reaction or intolerance is food avoidance.