Page 1484 - Clinical Small Animal Internal Medicine

1422 Section 12 Skin and Ear Diseases

avoided during the time of the diet. In particular, dog nal rechallenge. If a patient deteriorated after two days on
VetBooks.ir owners used to giving treats will often only be able to the old diet, then sequential rechallenges for four days
each should be sufficient. If the original rechallenge led to
complete a diet trial if suitable alternatives are agreed on
prior to starting the diet. For example, jerky of the meat
should probably be performed for two weeks each. This
used for the elimination diet can be home‐made or deterioration after one week, then sequential rechallenges
acquired in bigger pet stores as chews or treats. Dogs way, offending allergens can be identified and this knowl-
with a high affinity for scavenging need to be kept on the edge permits greater flexibility in feeding, although it
leash and cats with outdoor access are ideally kept requires more effort. And lastly, if a home‐cooked diet was
indoors. If those restraints are not possible for whatever used for the diagnosis, a commercial diet can be tried
reason, then an elimination diet trial may still be based on the feeding history of the patient.
attempted but the limitation of these more relaxed elimi-
nation diets is that a lack of improvement does not rule
out adverse food reaction in that patient, although some Therapy
patients may still improve when the intake of the offend-
ing allergen is limited at least to some degree. Ideally, avoidance of the offending food antigens is the
best way to treat adverse food reactions in dogs and cats.
If home cooking is used for long‐term management, care
Interpretation of the Outcome should be taken to create a well‐balanced diet and advice
of an Elimination Diet
from a veterinary nutritionist may be useful.
If a reevaluation after 6–8 weeks shows no improvement However, if avoidance is not possible or if flares due to
on an appropriate elimination diet and a secondary inadvertent ingestion of antigens are encountered, medi-
infection masking the improvement is not present, then cal treatment with antiinflammatory drugs also used for
adverse food reaction is ruled out and the diet trial does environmental atopic dermatitis may be attempted.
not need to be extended. If, however, there is some Glucocorticoids and ciclosporin are efficacious options
improvement seen, then in some patients it may be for dogs and cats suffering from cutaneous adverse food
necessary to continue the trial for up to 12 weeks. reactions, although anecdotal evidence indicates that
Improvement may be due to the elimination diet, con- higher doses are needed to achieve remission than with
current treatments, seasonal changes or other factors, so atopic dermatitis due to environmental allergens.
a rechallenge with the old diet is absolutely necessary for Oclacitinib (Apoquel; Zoetis) and lokivetmab (Cytopoint;
the diagnosis (although some owners will need some Zoetis) are also licensed for the treatment of allergic der-
convincing) and leads to deterioration of clinical signs matitis in dogs and thus are excellent, alternative options
within a few days. If after two weeks on the previous diet for controlling pruritus in canine patients with cutane-
there is no deterioration of clinical signs, adverse food ous adverse food reaction.
reaction is ruled out and improvement was due to other
factors. As soon as a deterioration is detected, the elimi-
nation diet is fed again and if clinical signs improve again Prognosis
(typically much faster than at the initial introduction of
the elimination diet), the diagnosis is confirmed. Once the diagnosis is established and offending allergens
Subsequently, there are three choices for the client. The are identified, the prognosis is excellent, although some
easiest is to stay on the elimination diet long term. However, rare dogs and cats will develop a reaction against the new
ideally, one food source after another is introduced again food antigens with time and will have to undergo a
gradually for a few days to weeks, depending on the origi- repeated change in their diet.

Further Reading

Bethlehem S, Bexley J, Mueller RS. Patch testing and allergic dermatitis in Switzerland. Vet Dermatol
allergen‐specific serum IgE and IgG antibodies in the 2008; 19(3): 150–5.
diagnosis of canine adverse food reactions. Vet Ricci R, Granato A, Vascellari M, et al. Identification of
Immunol Immunopathol 2012; 145(3–4): 582–9. undeclared sources of animal origin in canine dry foods
Olivry T, Bizikova P. A systematic review of the evidence of used in dietary elimination trials. J Anim Physiol Anim
reduced allergenicity and clinical benefit of food Nutr 2013; 97(s1): 32–8.
hydrolysates in dogs with cutaneous adverse food Roudebush P. Ingredients and foods associated with
reactions. Vet Dermatol 2010; 21(1): 32–41. adverse reactions in dogs and cats. Vet Dermatology
Picco F, Zini E, Nett C, et al. A prospective study on 2013; 24(2): 293–4.
canine atopic dermatitis and food‐induced