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tvpjournal.com | January/February 2016 | Today's VeTerinary PracTice 71 DERMATOLOGY DETAILS Peer Reviewed of current diagnostic methods and criteria for canine ad 8 as well as updated treatment recommendations. 9 DILEMMA 3. What is the best way to diagnose food allergy in dogs and cats? asking this question may be the single easiest way to start an argument among dermatologists. Food hypersensitivity is considered the third most common allergic condition diagnosed in dogs and cats after fea allergy and ad. it can be seen alone or in combination with these other allergies. The controversies surrounding diagnosis of food allergy illustrate our inability to make evidence- based statements about this disease. Pitfalls & Challenges on clinical examination, there are no specifc dermatologic signs that reliably differentiate food allergy from the other types of allergic disease (Figure 2 ). clues to the presence of food allergy include: • History of year-round skin disease that does not always respond to standard anti-itch therapy, such as glucocorticoids • Presence of concurrent gastrointestinal signs (eg, mild or intermittent diarrhea, vomiting, flatulence) • initial occurrence during puppyhood (though food allergy can occur at any age). Clinical Pearls The few things that experts are likely to agree on regarding food allergy are: • s erum allergy tests are not reliable for diagnosis. False-positive and false-negative results are common. • The only accurate test for food allergy is a carefully performed, strict, dietary restriction– provocation trial. FIGURE 2. Pruritic abdominal/inguinal region in a dog with erythematous infammatory allergic skin disease. Note the indication of chronic, low-grade infammation as evidenced by the "lacy" hyperpigmentation pattern. It is impossible to distinguish via clinical signs whether the important allergens for this dog are environmental, food-related, or a combination thereof. Pearls & Pitfalls: Key Points 1. Watch out for methicillin-resistant Staphylococcus (MRS) as a cause of canine pyoderma. • To minimize development of antimicrobial resistance, treat dogs with mild to moderate superfcial pyoderma with daily topical chlorhexidine, not antibiotics. • Steer your clients to good sources of information on MRS, such as wormsandgermsblog.com. 2. Diagnosis of canine atopic dermatitis is made using clinical criteria, not with an allergy test. For a recent review of clinical diagnosis, see reference 8; for up-to-date treatment recommendations, see reference 9. 3. It is typically impossible to differentiate food allergy from other allergies based on clinical criteria alone. Serum testing for food allergy is unreliable; for correct diagnosis, use a dietary restriction– provocation trial. 4. Early reports indicate that the isoxazoline compounds (afoxolaner and furalaner) may be excellent treatments for canine generalized demodicosis. Stay tuned for more studies. 5. Avoid long-term treatment of idiopathic feline eosinophilic granuloma complex diseases with injectable long-acting corticosteroids. Such use promotes both diabetes mellitus and treatment resistance. Instead, consider protocols using cyclosporine or chlorambucil.