Page 748 - Problem-Based Feline Medicine

740 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

additives except a pet vitamin. Use either a commer-
FOOD INTOLERANCE***
cial hypoallergenic diet or a homemade diet (see
page 741, Food intolerance, for details).
Classical signs
Intestinal biopsies will have mild to severe infiltrates
● Signs may range from intermittent
of inflammatory cells, which may be lymphocytic,
vomiting or diarrhea to pruritus, dermatitis
plasmacytic or eosinophilic or a combination of those
and other dermatologic signs.
cell types. There is currently no way to differentiate
the inflammatory infiltrates present in cats with
See main reference on page 669, Food sensitivity in
food allergy from those typically seen in cats with
“The Cat With Signs of Chronic Vomiting” for details.
IBD.
Clinical signs
Differential diagnosis
Adverse reactions to foods may be dermatologic or
The presence of dermatologic signs suggests that gastrointestinal and the percentage of signs associated
atopy and flea allergy as well as other dermatologic with either component is unknown.
conditions should be considered.
Intermittent to persistent vomiting (usually < 1 day)
Some cats will have GI signs only, and thus other dif- or diarrhea are the most common GI signs. Flatulence
ferentials such as food intolerance, parasites, and meta- and weight loss may occur.
bolic or neoplastic diseases should be considered.
Dermatologic signs may include pruritus, dermatitis or
Inflammatory bowel disease is also a disease that
alopecia.
mimics food allergy and is very difficult to differenti-
ate from it. In contrast to food allergy, food intolerance is a non-
immunologic reaction, and can occur on the first
exposure to the offending food or additive. A wide
Treatment
variety of food ingredients may be responsible.
Once an elimination diet has been identified that suc-
The relative occurrence of GI versus dermatologic
cessfully relieves the clinical signs, the cat should
signs and the importance of one or the other in the diag-
remain on that diet indefinitely. However, it is best
nosis of food intolerance is unknown. However, a com-
to try to identify a commercial diet that most
bination of dermatologic and GI signs should raise the
closely resembles the elimination diet so that the cat
index of suspicion of a food-related problem.
receives a nutritionally complete and balanced
diet. Most homemade elimination diets are not nutri-
Diagnosis
tionally balanced and are not suitable for long-term
maintenance. There is no diagnostic test for this problem other than
to observe a beneficial response to an appropriate
Cats may develop a hypersensitivity to any diet,
dietary trial for 1 week. Resolution of clinical signs is
including the so-called hypoallergenic diet, and in that
often apparent within 4 days.
situation, another novel protein source will need to be
selected. The best elimination diet to obtain a diagnosis is made
from a single novel protein and novel carbohydrate
Most cats with food allergy only respond partially or do
source with no added colors or preservatives. For the
not respond at all to prednisolone therapy or anti-
homemade diet, boiled white rice or potato (1/3 cup)
histamines.
and a novel meat source that the cat has not previously
The importance of preventing access to any food eaten (2/3 cups venison, rabbit, duck, ostrich, crocodile,
other than the elimination diet should be emphasized kangaroo, tofu, turkey, whitefish, etc.) are good options.
to the owners. Use food intended for human consumption, not pet meat.