Treating atopy: Keep patients comfortable without causing harm
Oct 01, 2005
In fighting allergies, our goal as veterinarians is to keep these patients comfortable without causing harm.
The first consideration in successfully treating an atopic patient is to know how to recognize atopy. It sounds simple, but there are many diseases masquerading as atopy. Atopy can start anywhere from 3 months to 3 years of age. It is likely repetitive, e.g. occurs at the same time every year. If you have a 12-year-old dog that you feel has "become" atopic, think again and go through the differentials to rule in atopy. Atopy likes to involve the face, feet and rectal area. The patient likes to rub his face, lick his feet and sometimes scoot. Besides being inhaled, we now know that percutaneous absorption of the allergen is important in canine atopy and what better place to absorb the allergen than the non-haired areas of the body, such as ventral feet and rectal area. Other manifestations of atopy include recurrent otitis, recurrent yeast or bacterial pyoderma including acral lick granulomas, ocular discharge, recurrent urinary tract infections, recurrent demodicosis, cutaneous histiocytosis and upper respiratory symptoms. Specific atopic breed idiosyncracies include German Shepherds, Labrador Retrievers and Boxers presenting with crusty, alopecic ear edges as seen in canine scabies, Siberian Huskies presenting with periocular and perioral crusting usually seen with zinc responsive dermatosis and various breeds presenting with cutaneous histiocytosis that responds to therapy for atopy, i.e. immunotherapy.
If a bacterial pyoderma is present and has not been treated or if yeast is found on skin smears, we will start by treating the pyoderma or yeast dermatitis first until total clearing plus one week. At that point, the owner is to call with a report as we need to know if despite clearing the lesions, the patient is still pruritic. If the patient is not pruritic but presents with a recurrent pyoderma, how long does it take to resolve the pyoderma, and more importantly, how soon does it recur?
These patients never seem to crawl out of their dermatologic problem because initially the steroid takes away the inflammation associated with the bacterial infection but goes on to immunosuppress the patient. So, at the end of the initial two to three weeks of antibiotics, the pyoderma is back even worse than before. The normal inclination is to repeat the steroid at a higher dose this time, and the same thing happens, but now the pyoderma is even worse than when you started.