Page 589 - Small Animal Clinical Nutrition 5th Edition

Adverse Reactions to Food 611

Adverse food reactions in dogs produce no set of pathogno- cases in two studies, suggesting a potential increased risk
(Carlotti et al, 1990; Rosser, 1993a).
monic cutaneous signs. A variety of primary and secondary skin
VetBooks.ir lesions occur and include: 1) papules, 2) erythroderma, 3) exco- patterns such as: 1) severe, generalized pruritus without lesions,
Dermatologic signs include several different clinical reaction
riations, 4) hyperpigmentation and 5) seborrhea sicca. Adverse
food reactions often mimic other common canine skin disor- 2) miliary dermatitis, 3) pruritus with self trauma centered
ders including pyoderma, pruritic seborrheic dermatoses, folli- around the head, neck and ears, 4) self-induced alopecia, 5)
culitis and ectoparasitism (MacDonald, 1993; Scott et al, pyotraumatic dermatitis and/or 6) scaling dermatoses (Mac-
2001). Twenty to 30% or more of dogs with suspected adverse Donald, 1993; Scott et al, 2001; Carlotti et al, 1990; White and
food reactions may have concurrent allergic disease, such as Sequoia, 1989; Rosser, 1993a; Guaguere, 1995; Roudebush and
flea-allergic or atopic dermatitis (Baker, 1974; Jeffers et al, McKeever, 1993; Medleau et al, 1986). In one study, angioede-
1991; Rosser, 1993; Hillier and Griffin, 2001; Jackson et al, ma, urticaria or conjunctivitis occurred in one-third of cats with
2005). Some dogs present with only recurrent bacterial pyoder- adverse food reactions (Rosser, 1993a). Adverse reactions to
ma, with or without pruritus, wherein all clinical signs resolve food may also be implicated in cats with the so-called
temporarily with antibiotic therapy (Scott et al, 2001; White, eosinophilic skin diseases such as eosinophilic plaques,
1986; Harvey, 1993). eosinophilic granulomas and indolent ulcers of the lips (Mac-
Food anaphylaxis is an acute reaction to food or food addi- Donald, 1993; Scott et al, 2001; Roudebush and McKeever,
tives with systemic consequences. The most common clinical 1993; Waisglass et al, 2006). Concurrent flea-allergy or atopic
manifestation in dogs occurs in localized form referred to as dermatitis triggered by environmental allergens may occur in
angioedema or facioconjunctival edema (Scott et al, 2001; up to 30% of cats with suspected adverse food reactions
Thompson, 1995). Angioedema is typically manifested by large (Carlotti et al, 1990; Rosser, 1993a).
edematous swellings of the lips, face, eyelids, ears, conjunctiva It has been suggested that moderate to marked peripheral
and/or tongue, with or without pruritus (Scott et al, 2001; lymphadomegaly is found in up to one-third of cats with der-
Thompson, 1995). The same types of substances that induce matologic manifestations of food allergy (Scott et al, 2001).
systemic anaphylaxis evoke angioedema (Thompson, 1995). Absolute peripheral eosinophilia occurs in 20 to 50% of feline
Most veterinary practitioners attribute angioedema solely to cases (Scott et al, 2001; White and Sequoia, 1989; Medleau et
insect envenomation (biting or stinging insects) but a number al, 1986).
of other common causes include food, drugs, vaccines, infec-
tions and blood transfusions (Scott et al, 2001; Thompson, GI Responses to Adverse Food Reactions in Dogs
1995; Nichols et al, 2001). These reactions usually occur with- and Cats
in minutes of allergen exposure and generally subside after one Gender predilections have not been established for GI disease
to two hours. resulting from adverse reactions to foods (Walton, 1967; Baker,
One of the authors (PR) has seen angioedema of the tongue, 1974). Similarly, there are no well-documented breed predispo-
palate and throat repeatedly in the same dogs after ingestion of sitions to GI food allergy, but Chinese Shar-Pei and German
mushrooms,domestic flowers or other plants.This presentation shepherd dogs are commonly affected. Furthermore, gluten-
resembles the oral allergy syndrome in people, which is a form sensitive enteropathy has been well documented in Irish setter
of contact urticaria confined almost exclusively to the orophar- dogs (Batt et al, 1984). A wide age range of patients can be
ynx (Sampson, 1993). Clinical signs in people include rapid affected, including dogs and cats as young as weaning age.
onset of pruritus and angioedema of the lips, tongue, palate and Every level of the GI tract can be damaged by food allergies.
throat. Signs usually resolve rapidly. This syndrome is most In dogs, cats and people, clinical signs usually relate to gastric
commonly associated with ingestion of various fresh fruits and and small bowel dysfunction, but colitis can also occur (Hey-
vegetables. Affected people are often primarily sensitized to man, 1989; Guilford and Badcoe, 1992; Sampson et al, 2001).
certain airborne pollens (especially birch or ragweed pollen); Vomiting and diarrhea are prominent features. The diarrhea
the immunologic basis for this syndrome is IgE cross reactivi- can be profuse and watery, mucoid or hemorrhagic (Guilford
ty. One report details the clinical and immunologic findings in and Badcoe, 1992; Baker, 1990). Intermittent abdominal pain,
a dog that developed oral allergy syndrome to tomato after intermittent diarrhea, weight loss, flatulence, irritable de-
prior sensitization with Japanese cedar (Fujimora et al, 2002). meanor, soft feces and increased frequency of defecation are
also seen (Guilford et al, 2001; Loeffler et al, 2004). Concurrent
Dermatologic Responses to Adverse Food Reactions cutaneous signs may be seen. GI disturbances occur in up to
in Cats half of dogs and cats with cutaneous manifestations of food
The age of cats affected with food sensitivity has ranged from hypersensitivity (MacDonald, 1993; Scott et al, 2001; Loeffler
six months to 12 years; a gender predisposition has not been et al, 2004, 2006). In experimentally induced food hypersensi-
documented (Carlotti et al, 1990; White and Sequoia, 1989; tivity, the most common clinical signs are diarrhea, an increase
Rosser, 1993a; Guaguere, 1995; Roudebush and McKeever, in the number of bowel movements and occasional vomiting
1993; Medleau et al, 1986). In one study, almost half the cats (Roudebush and McKeever, 1993; Frick, 1991). Pruritic dogs
developed the disease by two years of age (Rosser, 1993a). with more than three bowel movements per day are more like-
Siamese or Siamese cross cats accounted for nearly one-third of ly to have an adverse reaction to food as part of the reason for