Southern style itch with grits-sure fire methods to control atropy and complicating problems (Proceedings)
The combination of clinical diseases observed in pruritic dogs has been a consistent finding over the decades. The occurrence of the atopic dog with flea allergy dermatitis and secondary bacterial pyoderma led to the common expression in th '80's of the Southeastern Triad not that the S.E. has any royalty rights to this combination of clinical problems. Certainly, throughout North America, anywhere fleas are found the triad is observed. The incidence of atopic dermatitis in the Southeastern dog is, without exception, the largest single disease responsible for pruritus. A large proportion of the atopic dogs concurrently have flea allergy (70% or>) and a small percentage may have cutaneous adverse reaction to food (aka food allergy- 15%). Factors related to the preponderance of atopy can only be postulated as there is no single factor responsible in this multifaceted disease. While genetic predilection represents a strong basis for the disease, environmental factors weigh in with near comparable affect. Increasing number of pedigree dogs seems to be an observation although overinterpretation of this finding is cautioned since the owner's of pedigree dogs are those most likely to solicit veterinary attention for their atopic pet. Much understanding of the immunological basis has occurred in the last 25 years with more novel therapeutics becoming part of our daily choice in treating this condition. The development of more refined serum allergy testing has provided veterinarians in all parts of the country to include the option of allergen specific immunotherapy as a choice for the treatment of atopic dermatitis with the expectation of reasonable clinical outcome. Immunological evidence now supports the events that are associated with immunotherapy. Randomized-controlled studies continue to be reviewed with increasing awareness of the outcome of our treatment choice.
Flea allergy continues to be a commonly recognized entity most often associated with atopy and a resurgence observed in the Southeast within the last 8 years. The development of more novel chemicals for flea control has certainly enhanced our success for adequate control although perseverance of the flea as a consequence of many factors assures its survival. While newer products become an asset to our flea control efforts, it does not preclude the need for appropriate history and the continued effort of an integrated approach toward flea control. Maximizing success still requires a complete overview of the problem including the habitat, potential flea population dynamics, pets and non-pets that contribute to the problem as well as the identification of the flea allergic animal. The flea is still a survivor and would do well on one of those reality shows or a sequel to Ironman II.
Bacterial Pyoderma has seen a tremendous change in the past decade with prevalence observed in more than 75% of referral atopic dogs. The recognition of Staphylococcal organism's ability to mutate with resulting resistance is a complex problem with ever increasing incidence. The need for being a good custodian of antibiotic therapy places more responsibility on the practicing veterinarian to follow guidelines to optimize clinical response and minimize the development of resistance factorsThe prevalence of yeast dermatitis rounds out the Southeastern Triad for the "Plus One". Three decades ago this condition was only being recognized where today there are cases documented on a daily basis. As with the bacterial pyoderma, malassezia is an opportunist and is almost always observed secondary to a primary disease with atopy being the most common. The occurrence of malassezia is likewise almost always observed with co-existing bacterial infection although it may be observed as an independent facultative pathogen. Research has demonstrated that dogs harboring organisms resulting in disease will likely develop an immediate hypersensitivity reaction to the yeast further potentiating the pruritus associated with metabolic byproducts of the yeast. Recognition and treatment of this component becomes an important part of the overall treatment plan. Microscopic diagnostic evaluation should be performed prior to treatment and during the reassessment. Principles of therapy should be considered similar to the use of antibiotics.
Patterns of pruritus are beneficial in development of a differential diagnostic list. Pruritus affecting the head (face &/or ears), ventrum and extremities include three prominent differentials: 1. Canine atopy 2. Adverse food reaction (food allergy) and 3. Canine scabies. These diseases provide the basis for the evolvement of a basic working list of diseases to initiate diagnostic evaluation. Canine scabies can be easily ruled out despite the lack of disease confirmation from multiple skin scrapings. Dietary trials are usually successful in identifying a diet related problem (remember that the vast majority of food related allergy animals also have concurrent canine atopy). Another concurrent allergic relationship is the presence of flea allergy. The distribution pattern of flea allergy dermatitis in the dog specifically affects the pelvic region with the dorsal lumbar sacral involvement as well as caudal-medial thighs and inguinal area which is quite unique compared to canine atopy. Occasionally food allergy may have the same pattern as flea allergy. Canine atopy does not typically have papules. When they are observed, it is always best to think of concurrent infection first since atopy is less commonly associated with a popular dermatitis.