Cutaneous Adverse Food Reaction Doesn’t Mean a Life of Bland, Unbalanced Diets

The human-animal bond is the treasured connection between a pet and the pet owner. There are several factors that contribute to the quality of this bond in regards to companion animals. One of the most important aspects of this integral connection is the quality and type of nutrition in the pet’s diet. It is often said that if one is concerned about the well-being of the family dog, then one should look no further than what is in his or her stomach. Dietary nutrition plays several crucial roles in the development of young dogs and the maintenance of health throughout life. There are several disease processes that have been associated with poor nutrition. For example, feeding methods, feed consumption, specific nutrients, and electrolyte balances within the diet have all been shown to influence hip dysplasia in dogs. Therefore, it should be noted that diseased dogs may have different nutritional requirements from generally healthy dogs and specific diets should be fed.

The pet owner can sometimes become overwhelmed with the selection of dietary options available for their beloved pets. Thankfully, dogs display considerable dietary flexibility to accommodate this fact. There are roughly 400 distinct dog breeds recognized worldwide. These different breeds represent a large variation in body size and weight. Dogs have the ability to consume and utilize energy from both animal-based products and a variety of edible plant-based foods. Within the various breeds, the behavior of an individual is controlled by numerous factors. Diet should be considered an important contributor to the social interactions and mental wellbeing of both humans and dogs. Studies have shown that diets rich in vitamins and minerals may decrease anti-social behavior in animals. When fed a diet containing poorly balanced nutrition, dogs can develop similar cognitive deficits and neuropathology as seen in aging humans and elderly suffering from dementia. Research studies focused on this topic have shown that dog food enriched with antioxidants decreased the rate of cognitive decline in aged beagle dogs.

Proper nutrition also plays a pivotal role in canine hypersensitivity disorders. These conditions, specifically atopic dermatitis (AD), can be frustrating to manage for both the pet owner and for the veterinary clinician. It affects roughly 10% of the canine population making it a common underlying condition. Atopic dermatitis in the canine patient is often due to environmental allergens, but can be a manifestation of cutaneous adverse food reaction (CAFR). This means that a patient presenting with AD due to a dietary allergy can appear clinically identical to one with AD due to aeroallergens. It is up to the veterinary clinician to differentiate between the two by means of history and exclusion. There have been several recent studies examining different aspects of CAFR and its importance as an underlying condition. Once diagnosed, management of this condition with commercially available diets and treats may be a welcomed realization for millions of pet owners and pets alike.

In general, CAFR can manifest at any age. AD will typically begin between the ages of 6 months and 3 years. Dogs diagnosed with food-induced AD tended to be younger (< 1 year) or older (> 6 years) than those with aeroallergen-induced AD. As mentioned previously, canine AD has been shown to have a genetic basis. This has also led to the realization that several breeds are at an increased risk. Predisposed breeds include West Highland white terriers, Labrador retrievers, golden retrievers, boxers, French bulldogs, German shepherds, and cocker spaniel dogs. There does not appear to be an overwhelming sex predilection for canine AD with the exception of male golden retrievers and female boxers being slightly overrepresented.

The most common clinical sign seen with canine CAFR is pruritus with greater than 90% of affected dogs experiencing this. In some cases, owners may report this as being an intense pruritus that may or may not respond to anti-inflammatory doses of glucocorticoids. The veterinary clinician should keep in mind that pruritus can manifest in several ways in the canine patient, including excessive grooming, licking, rubbing, and head shaking. Many patients will experience a generalized pruritus, but specific areas, such as the paws, ventrum, or ears may be focal points of discomfort.

The distribution of lesions associated with the canine AD syndrome characteristically affects specific body areas, such as the flexor aspect of the elbow, the interdigital region, the axillary region, the inguinal region, and the face. In the early stages of this condition, primary lesions (e.g. erythema, papules) are predominantly found over these areas. As the syndrome becomes chronic, secondary lesions (e.g. excoriations, lichenification, alopecia) are noted with the same distribution. The owner may note that the clinical signs can be seasonal or non-seasonal depending on the offending allergen levels in the environment.

There is still much that is unknown about the pathogenesis of CAFR and it remains the center of a considerable amount of research. It is imperative that the veterinary clinician remember to develop a treatment plan for the individual patient that centers on the prevention of flares. No plan is perfect and flares of the CAFR should be anticipated. The pet owner should be counseled on the expected flares and the means on which to control them without panic. The goal in managing CAFR is to improve the quality of life for the canine patient and improve the human-animal bond.

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