Zinc Responsive Dermatosis

Note: We do not currently have a health liaison for this disorder. If you would like to volunteer, please contact president@samoyedhealthfoundation.org and we will be happy to answer any of your questions. For a description of the position, please click on disorder health information liaison.

Thank you to Hazel Fitzgibbon for providing this disorder information.

Summary

Zinc Responsive Dermatosis is a skin disorder that responds to treatment with zinc. It is one of the manifestations of zinc deficiency. The deficiency can be dietary, or in some Arctic breeds, Samoyeds being one of them, it can be an inherited disorder of zinc absorption.

Signs and Symptoms

Initial symptoms are thick scaly/crusty patches and alopecia (hair loss) around the eyes and muzzle. This can also be seen on the ears, hocks, under the pads and around the reproductive organs in both dogs and bitches. Thick crusting occurs on pressure points, e.g. elbows. Hair may be dull and harsh and secondary skin infections can occur. Many dogs will scratch or chew at affected areas due to itching. Symptoms may occur at any age, but typically are first seen in young adult dogs.

Extended zinc deficiency can cause other problems, including lack of appetite and ensuing weight loss, slow wound healing, keratitis (inflammation of the cornea) and conjunctivitis (inflammation of the conjunctiva – the tissue that covers the inner eyelid and the white of the eyeball). Lymphadenopathy (enlarged lymph nodes) can occur in very young dogs.

Causes

There can be several reasons for zinc deficiency:

Dietary:

Feeding incomplete feeds with insufficient zinc
Over feeding other mineral supplements, especially calcium, iron and copper
Feeding excess phytates, a substance found in some cereal-based diets that interferes with zinc absorption in the intestine

Hereditary:

Malabsorption, commonly thought to be a recessive, inherited disorder in Arctic breeds

Risk Factors

Related dogs with disorder
Arctic breed (Samoyed, Alaskan Malamute, Siberian Husky)

Diagnostic Tests

Skin problems are generally hard to diagnose but this one has definite changes that can be easily recognized. Diagnosis can be made by microscopic analysis of a punch biopsy of the skin. This biopsy can be done under local anesthetic. The diagnosis is confirmed by the dog’s response to zinc supplementation.

Treatment Guidelines

Note: Treatment of animals should only be performed by a licensed veterinarian. Veterinarians should consult the current literature and current pharmacological formularies before initiating any treatment protocol.

If the cause of the zinc deficiency is dietary, an improvement in diet and short term zinc supplementation can usually bring improvement in a month or two.

If the cause is hereditary, the zinc supplementation will usually relieve symptoms, but may have to continue lifelong. Zinc can be administered by mouth but care must be taken not to overdose an affected dog as zinc poisoning can occur. The correct dose must be determined for each dog. Larger doses can cause vomiting. If large doses are needed, they can be divided and given, with food, several times a day. In some cases zinc is given intravenously. Once a correct dosage is determined with the aid of your Veterinary Surgeon, it will probably have to be maintained for the life of the animal.

Symptoms will recur if the supplementation is not maintained. Even as little as one missed dose can cause recurrence. Symptoms may occasionally flare up whilst supplementation is being administered. If this happens, they are usually of a short term duration, 2 – 3 weeks, and generally resolve spontaneously as long as the maintenance dose is still given.

Antiseborrheic shampoo can be used for relief of affected areas, but care must be taken when using around the eyes. Topical relief such as Aloe Vera gel for immediate relief can be used, although sparingly.

Management

The gene(s) responsible for poor absorption appear to be recessive, but there are as yet no genetic markers in evidence in any of the affected breeds. Spaying females with the disorder has been reported to allow some owners to decrease, or cease zinc supplementation.