Zinc Responsive Dermatosis in Dogs

Zinc is a necessary nutrient for maintaining healthy skin and hair. Dogs who do not get enough zinc can develop zinc-responsive dermatosis (ZRD). Dogs showing symptoms of zinc-responsive dermatosis benefit from prompt veterinary evaluation.

Zinc-responsive dermatosis is rare in dogs. Dogs with unbalanced diets are at risk of zinc deficiency, which can lead to dermatosis. Dogs on homemade or specialty diets are at higher risk of nutrient deficiencies. Excess supplementation of canine diet without veterinary guidance may also contribute to development of ZRD in some dogs.

The severity of zinc-responsive dermatosis depends on which type is present, and whether secondary infections develop.

Type 1 zinc-responsive dermatosis is caused by a genetic defect in intestine function. At-risk breeds include:

• Siberian huskies
• Alaskan malamutes
• Bull terriers
• Doberman pinschers
• Great danes

Type 2 ZRD is most prevalent in the puppies of large, rapidly growing breeds.

In some cases, other breeds of dog have this form of dermatosis as a result of severe intestinal disease.

Dogs with zinc-responsive dermatosis are more vulnerable to bacterial and fungal infections such as Malassezia.

There are 3 types of zinc-responsive dermatosis in dogs, which all have their own root causes.

Type 1 is caused by a genetic defect which prevents the intestines from absorbing zinc properly, even when there is plenty of zinc in the diet.

Type 2 is caused by specific minerals in the dog’s diet that interfere with zinc absorption, even when there is plenty of zinc in the diet. Typically, this is related to dietary supplements that contain plant-based antioxidants and calcium.

Type 3 zinc-responsive dermatosis is also known as “generic food disease” because it occurs in dogs who eat poor quality dog food that do not contain sufficient zinc.

The main symptoms of zinc-responsive dermatosis are crusty, scaly, thick lesions on the skin or mucous membranes.

Lesions are often accompanied by loss of hair.

Diagnosis of zinc-responsive dermatosis aims to rule out other possible causes of the symptoms. Most cases of zinc-responsive dermatosis are diagnosed based on symptoms improving after increasing zinc in the diet. Other diagnostic tools include:

• Physical examination
• Nutritional history
• Skin biopsy
• Measurement of zinc levels in the blood or hair

Treatments include:

• Improving the diet to include sufficient zinc
• Eliminating supplements with plant-based antioxidants and calcium, in order to improve zinc absorption
• Supplementing with zinc

The prognosis for dogs with type 1 zinc-responsive dermatosis depends on the amount of zinc the intestine is able to absorb. Dogs with no zinc absorption typically do not survive longer than 18 months. The prognosis for dogs that absorb some zinc is good with life-long zinc supplementation.

The prognosis for dogs with type 2 and type 3 zinc-responsive dermatosis is good with the elimination of zinc-blocking minerals from the diet or improving the diet. Typically, the lesions resolve within 6 weeks.

Type 1 zinc-responsive dermatosis is hereditary. Avoiding breeding dogs with this disease is recommended.

Types 2 and 3 are preventable by ensuring sufficient zinc in the diet and avoiding supplements that block the absorption of zinc.

Type 1 is very rare, and some reports suggest that it has been bred out completely.

Types 2 and 3 are more common, but are still rare overall.

• Zinc supplementation
• Improving the diet
• Eliminating phytates and calcium supplements