Zinc-responsive dermatosis in northern-breed dogs: 17 cases (1990-1996).

ABSTRACT

OBJECTIVE: To determine the response rate of zinc-responsive dermatosis to zinc supplementation, the optimal dosage of zinc required for resolution of lesions, the rate of recurrence of lesions, and to develop recommendations for maintenance dosages of zinc to be administered to dogs with this type of zinc-responsive dermatosis. DESIGN: Retrospective case series. ANIMALS 17 northern-breed dogs with a diagnosis of zinc-responsive dermatosis. PROCEDURE Histologic evaluation of skin biopsy specimens and review of medical records. Additional information was obtained from veterinarians and owners via a telephone questionnaire. RESULTS: In 12 of 17 dogs, lesions were unilateral initially, then became symmetrical as the disease progressed. Pyoderma was evident in 5 of 17 dogs, whereas 10 were pruritic. Most lesions initially developed between September and April, and 12 of 17 dogs developed lesions in February, October, and November. Initial dosages of zinc supplement ranged from 0.8 to 4.6 mg/kg of body weight/d (0.36 to 2.09 mg/lb/d). Effective/ maintenance dosages ranged from 0.5 mg/kg (0.23 mg/lb), twice weekly, to 8.0 mg/kg/d (3.6 mg/lb/d). Fifteen of 17 dogs had complete resolution of lesions after zinc supplementation. Lesions recurred in 9 of 16 dogs. Approximately half of the recurrent lesions were a result of a missed dose or a decrease in dosage or frequency of zinc supplementation. CLINICAL IMPLICATIONS An initial dosage of zinc supplement of 1.0 mg of elemental zinc/kg (0.45 mg of elemental zinc/lb), PO, every 24 hours is recommended. Treatment should be continued for 1 month to determine response to treatment, and the daily dosage should be increased by 50% if the initial dosage is not effective. Dogs are prone to recurrence of lesions if a dose of zinc is missed or the dosage or frequency is decreased.