Page 643 - Small Animal Clinical Nutrition 5th Edition

Skin and Hair Disorders 665

Answers and Discussion
1. Underlying allergic disease due to atopy, flea allergy or food allergy could cause the pruritus, dermatitis and seborrhea seen in this
VetBooks.ir patient and predispose the dog to secondary pyoderma. Atopy can be ruled out with intradermal and in vitro allergy testing.There
was no evidence of flea infestation.The clinical improvement was probably due to elimination of the superficial bacterial pyoderma.
2. Supplementing the current food with fatty acids or changing to another food with higher fatty acid levels may benefit this patient.
Fatty acid therapy alone is rarely successful in controlling moderate to severe pruritus in most patients with skin disease, but may
be effective when used concurrently with other therapies. A synergistic effect between fatty acid and antihistamine administra-
tion has been documented in some clinical trials involving allergic dogs.
Progress Notes
Intradermal skin testing was positive for a few weed antigens. Blood was drawn for in vitro (ELISA) allergy testing. Positive reac-
tions were found to house dust mites, several trees, several grasses and several weeds, including ragweed. The probable diagnosis
was atopy with secondary superficial pyoderma and seborrhea.Treatment was initiated with an antihistamine (hydroxyzine, 25 mg,
b
t.i.d.) and a fatty acid supplement (1 capsule twice daily with food) that delivered 500 mg of eicosapentaenoic acid (EPA) daily in
addition to the fatty acids in the food. Bathing with the shampoo was continued.
Eight weeks later the owners reported some improvement in the level of pruritus, but evidence of self-induced alopecia persist-
ed (barbered hairs on the dorsal lumbar region). The skin was also erythematous; salivary staining was evident in these areas. The
bathing, fatty acid supplementation and hydroxyzine administration were continued. Hyposensitization injections were started
using allergens identified by the ELISA performed two months earlier. The veterinary therapeutic foods were fed until they were
gone (about two weeks). At that time, the owner began feeding the dry and moist grocery store brand foods fed previously.
The owner reported significant improvement eight weeks later. There were no areas of visible erythema on the skin, but salivary
staining persisted on all four feet. There was mild oiliness and scale accumulation on the dorsum. Bathing, hydroxyzine adminis-
tration, hyposensitization injections and fatty acid supplementation were continued.

Further Discussion
The optimal dose of omega-3 fatty acids and γ-linolenic acid for control of inflammation and pruritus has not been established.
The levels of these fatty acids in the grocery brand foods the patient was eating were unknown. The venison and potato veterinary
therapeutic foods provided approximately 50 mg of omega-3 fatty acids per day to the patient. The supplement provided an addi-
tional 500 mg of EPA, which markedly increased total omega-3 intake.This dosing level may have been enough additional omega-
3 fatty acids (36 to 40 mg EPA/kg body weight) to benefit this patient. The clinical improvement was probably attributable to the
combination of all therapies used in this dog.

Endnotes
a. IVD Limited Ingredient Diets. Nature’s Recipe Pet Foods, Corona, CA, USA.
b. 3V Caps Skin Formula. DVM Pharmaceuticals, Miami, FL, USA.
Bibliography
Paradis M, Scott DW. Nonsteroidal therapy for canine and feline pruritus. In: Kirk RW, Bonagura JD, eds. Current Veterinary
Therapy XI. Philadelphia, PA: WB Saunders Co, 1992; 563-566.
Roudebush P. Consumption of essential fatty acids in selected commercial dog foods compared to dietary supplementation: An
update. In: Proceedings. Annual Members Meeting AAVD & ACVD. Norfolk, VA, 2001: 53-54.
Scott DW, Miller WH, Griffin CE. Small Animal Dermatology, 5th ed. Philadelphia, PA: WB Saunders Co, 1995; 211-218.