Page 775 - Problem-Based Feline Medicine

34 – THE CAT WITH SIGNS OF LARGE BOWEL DIARRHEA 767

A response should be seen with the non-offending diet, Clinical signs
whether commercial or homemade, within 4 days if
Food allergy is an adverse reaction to food (usually
there is total compliance with the diet.
protein, but may also be carbohydrate) that is immuno-
Dietary indiscretion is a presumptive diagnosis made logic (i.e. food allergy, hypersensitivity, delayed hyper-
based upon the history of eating lizards, beetles, plants, sensitivity).
etc., lack of other physical examination or diagnostic
The signs are acute, and often include vomiting or
(fecal examinations negative for parasites, normal fecal
inappetance in addition to diarrhea.
cytology, normal blood work and radiographs) findings.
The GI signs of food allergy are usually chronic and
Differential diagnosis may be intermittent. They can involve vomiting
alone, diarrhea alone, or a combination.
Food allergy is the major differential diagnosis for cats
Clinical signs of food allergy may also involve the
with food intolerance and it is very difficult to distin-
skin around the head and neck (pruritus, alopecia, der-
guish the two conditions clinically. Since the treat-
matitis, otitis) as well as the GI tract, and vomiting or
ment for both food intolerance and food allergy is the
diarrhea is reported.
same and the response to treatment should be identi-
cal, it is probably unnecessary in clinical practice to Those cats that develop GI signs usually have vomiting
differentiate the two conditions. or small bowel diarrhea, however, some cats will
develop colitis due to food allergy and have large bowel
Treatment diarrhea, or episodes of mucoid feces.
In most cats, treatment of dietary indiscretion is symp-
Diagnosis
tomatic (e.g. feeding a high-fiber diet for cats with large
bowel signs, low-residue diet if both large and small Diagnosis of food allergy is based on cessation of clin-
bowel signs are present), with judicious use of antibiotics ical signs upon elimination of the offending sub-
(for bacterial flora manipulation) and fluid support if stance from the diet, and recurrence of signs when the
needed. Prevent access to the offending material. substance or diet is re-introduced to the cats.
Treatment of food intolerance involves the removal A response should be seen with the hypoallergenic
of the offending substance from the diet, which is diet, whether commercial or homemade, within 4 days
usually achieved by changing to a commercial diet con- if there is total compliance with the diet and the cat
taining different protein or carbohydrate sources, and no has not been previously sensitized to ingredients in
additives, flavorings, colorings, etc. the diet.
Intradermal skin testing and measurement of food-
FOOD ALLERGY (DIETARY specific IgE in the serum have been advocated by
HYPERSENSITIVITY)* some, but are fraught with both false-negative and
false-positive results since most food allergies are not
Classical signs mediated by IgE. Also, IgE present in the skin does not
correlate to IgE in the GI tract.
● GI signs (vomiting, diarrhea, weight loss,
inappetance) are most commonly Gastroscopic food sensitivity testing has not been
associated with this condition. reported to be useful in cats.
● Dermatologic signs (pruritus, alopecia,
papules) may accompany the GI signs in Differential diagnosis
some cases.
Colonic IBD is the major differential for cats with
See main reference on page 667 (The Cat With Signs of severe or persistent signs, and endoscopic biopsy will
Chronic Vomiting) for details. not distinguish between eosinophilia or inflammation