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1054.e2 Zinc-Responsive Dermatosis

Zinc-Responsive Dermatosis
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• Zinc absorption is also negatively affected
BASIC INFORMATION
by essential fatty acid deficiency, high levels treatment is usually noted within 6 weeks.
Lifelong treatment is required.
Definition of iron in water, or prolonged diarrhea. • Syndrome II: correct diet. Lesions improve
Uncommon but well-recognized zinc-responsive • It is suspected that low zinc levels cause poor in 2-6 weeks in most cases. Some animals
scaling disorder of the skin can be hereditary lytic enzyme function (affecting epidermal may benefit from a short course of zinc
or secondary to a dietary imbalance. maturation) or increased epidermal turnover supplementation (see above).
rate (leading to hyperkeratosis). • Essential fatty acid supplementation (omega-3
Epidemiology and omega-6) may aid zinc absorption.
SPECIES, AGE, SEX DIAGNOSIS
• Syndrome I: age of onset is typically 1-3 Chronic Treatment
years; range is 2 months to 11 years. Diagnostic Overview • Treatment for patients with syndrome I is
• Syndrome II: most common in young, The diagnosis is based on signalment, history, usually lifelong.
rapidly growing puppies and clinical and histopathologic findings. • It has been suggested that low doses
(0.15 mg/kg PO q 24h) of prednisone or
GENETICS, BREED PREDISPOSITION Differential Diagnosis prednisolone can be added to the regimen
• Syndrome I: Alaskan Malamute, Siberian • Superficial necrolytic dermatitis (hepatocu- to aid gastrointestinal (GI) absorption
Husky, and Samoyed; also reported in taneous syndrome) (induction of metallothionein) if response
Pharaoh hounds, Doberman pinschers, • Dermatophytosis is inadequate. Improved response may also
Great Danes, and possibly Boston terriers; • Nutritionally deficient diets be due to an antiinflammatory effect on the
lethal acrodermatitis due to a genetic defect • Demodicosis skin.
in zinc absorption has been described in bull • Pemphigus foliaceus • Different forms of zinc may be tried if
terriers there is poor response to therapy. It has
• Syndrome II: any breed; reported in Great Initial Database been suggested that IV sterile zinc sulfate
Danes, Doberman pinschers, and several • Skin scrapings (p. 1091): generally negative administration (e.g., 10-15 mg/kg diluted
other breeds • Fungal (dermatophyte) culture: expect 1 : 1 with saline and infused slowly) may
negative result help animals that do not respond to oral
RISK FACTORS • Skin cytologic exam to assess possible second- supplementation because of poor intestinal
Rapidly growing puppies fed diets deficient ary bacterial or yeast overgrowth absorption (treatment may be necessary
in zinc or high in phytates (high plant/grain • If diarrhea is noted, perform fecal flotation in Pharaoh hounds). Treat weekly for at
content) or calcium and any additional appropriate testing. least 4 weeks, then every 1-6 months as
maintenance.
Clinical Presentation Advanced or Confirmatory Testing
DISEASE FORMS/SUBTYPES • Skin biopsy: epidermal parakeratotic hyper- Drug Interactions
• Syndrome I: hereditary keratosis is the most common finding, and • Zinc salts may reduce the absorption of
• Syndrome II: dietary follicular parakeratosis is highly suggestive. some fluoroquinolones and chelate oral
• Zinc concentration in serum or hair: may tetracyclines, reducing the absorption of zinc.
HISTORY, CHIEF COMPLAINT be abnormal but analysis is difficult and • Penicillamine and ursodiol may inhibit zinc
• Owner may note scaling and crusting unreliable absorption.
dermatosis.
• Pruritus may precede development of other TREATMENT Possible Complications
clinical signs and occurs in almost one-half • Emesis: zinc in the form of methionine or
of cases. Treatment Overview acetate may be less likely to cause stomach
The goals of treatment are to resolve the scaling irritation. If vomiting occurs, lower the dose,
PHYSICAL EXAM FINDINGS ± alopecia and inflammation, control the sec- or give with food.
• Focal cutaneous erythema and alopecia ondary microbial dermatitis, and ensure the • Large doses of zinc can inhibit copper
progress to scaly and crusted lesions. patient is eating a nutritionally balanced diet. absorption in the intestine.
• Secondary microbial (bacterial and yeast) • IV zinc sulfate treatment may result in cardiac
dermatitis Acute General Treatment arrhythmias. Always monitor electrocardio-
• Predilection sites: periocular, ears, bridge of • Assess and correct dietary deficiencies. gram during administration.
the nose, perioral, footpads, pressure points • Treat secondary bacterial or yeast dermatitis • Zinc toxicosis (p. 1053)
on limbs; scrotum, prepuce, perianal region, (pp. 614 and 851).
and vulva may also be affected. • Keratomodulating shampoos (e.g., salicylic PROGNOSIS & OUTCOME
• Dull, dry coat acid/sulfur shampoos) to remove scales and
• Some puppies with syndrome II present with crusts • Syndrome I: fair to good prognosis for most
depression, anorexia, delayed growth, fever, • Syndrome I: supplementation is recom- animals
and lymphadenopathy. mended at 1-3 mg/kg of elemental zinc • Syndrome II: excellent prognosis if dietary
daily. Start at the lower dose, but in some deficiency is corrected
Etiology and Pathophysiology cases, doses on the order of 2-3 mg/kg may
• Genetic defect involving zinc absorption be needed. Zinc gluconate (generic) 5 mg/ PEARLS & CONSIDERATIONS
reported in Alaskan Malamutes kg PO q 24h or zinc sulfate 10 mg/kg PO
• Diets high in calcium or phytates (plant/ q 24h. Zinc sulfate tablets may be crushed Comments
grain products) bind zinc, decreasing and mixed with food to enhance absorption • Zinc chelated with an amino acid such as
absorption and decrease gastric irritation. Response to methionine offers greater bioavailability

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