March 23, 2017

Prevalence of Cutaneous Adverse Food Reactions in Dogs and Cats

According to a review recently published in BMC Veterinary Research, the prevalence of CAFRs in dogs and cats varies with the presenting signs and type of diagnosis.
By Laurie Anne Walden, DVM, ELS
Cutaneous adverse food reactions (CAFRs) comprise both food hypersensitivities (mediated by the immune system) and food intolerances (not involving the immune system). CAFRs are also known by the less descriptive term food allergies.
 
According to a review recently published in BMC Veterinary Research, the prevalence of CAFRs in dogs and cats varies with the presenting signs and type of diagnosis. In the studies analyzed, CAFR prevalence was low overall—approximately 1% of all dogs and 0.2% of all cats seen at clinics included in the reports. However, prevalence was as high as 62% among dogs with allergic skin disease and 21% among cats with pruritus.
 
“Our objectives were to systematically review the literature to determine the prevalence of CAFRs among dogs and cats with pruritus and skin diseases,” write Dr. Thierry Olivry (North Carolina State University) and Dr. Ralf Mueller (Ludwig Maximilian University, Munich, Germany). They note that variation in CAFR prevalences reported in published studies could be due to differences in geographic populations, groups of animals included, or the method of diagnosis.
 
Drs. Olivry and Mueller reviewed 28 research articles published from 1980 to 2016. The articles included information gathered from clinics in 15 countries and from worldwide surveys. All but two of these studies were conducted at specialty clinics or university hospitals. The diagnosis of CAFR was based on the response to an elimination diet in 25 studies; the method of diagnosis was not specified in 3. “Importantly, in only four articles was an elimination diet performed in the entire population of study patients,” they write.
 
CAFR prevalence rates among dogs and cats with various clinical signs or diagnoses were as follows:
  • Dogs presenting with any diagnosis: median, 1%
  • Dogs with skin diseases: median, 6%; range, 0% to 24%
  • Dogs with pruritus: median, 18%; range, 9% to 40%
  • Dogs with any allergic skin disease: median, 20%; range, 8% to 62%
  • Dogs with cutaneous lesions consistent with atopic dermatitis: median, 29%; range, 9% to 50%
  • Cats presenting with any diagnosis: 0.2%
  • Cats with skin diseases: median, 5%; range, 3% to 6%
  • Cats with pruritus: median, 16%; range, 12% to 21%
  • Cats with any allergic skin disease: median, 10%; range, 5% to 13%
 
The chief limitation of the review was variation in the methods of diagnosing CAFR among the included studies, say Drs. Olivry and Mueller. They add that the reported CAFR prevalence was probably lower in studies in which elimination diet trials were not performed in all patients.
 
The authors recommend conducting elimination diet trials to rule out CAFRs in dogs and cats with nonseasonal pruritus or signs consistent with allergic skin disease.
 
 
Dr. Laurie Anne Walden received her doctorate in veterinary medicine from North Carolina State University. After an internship in small animal medicine and surgery at Auburn University, she returned to North Carolina, where she has been in small animal primary care practice for over 20 years. Dr. Walden is also a board-certified editor in the life sciences and owner of Walden Medical Writing, LLC. She works as a full-time freelance medical writer and editor and continues to see patients a few days each month.

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