Dog Health: Ichthyosis, Canine Ichthyosiform Dermatosis

Breeds at Risk

This condition occurs in a number of breeds, including Doberman Pinscher, Rottweiler, Irish Setters, Collie, English Springer Spaniel, Cavalier King Charles Spaniel, Golden Retriever, Labrador Retriever, American Bulldog, and terriers including West Highland White Terrier and Jack Russell Terrier.

In dogs, this hereditary condition affects the eyes and skin. The eye signs are due to keratoconjunctivitis sicca, a common ocular disease in the dog, but rarely of congenital origin. The skin signs are of an ichthyosiform dermatosis.

Ichthyosis in Humans

In human beings, ichthyosis is a similar disease, mainly inherited and with a neonatal onset, and sometimes accompanied by other developmental defects. In the Cavalier King charles spaniel, the coat abnormality may be noted at birth by the breeders as a 'curly coat', with deterioration of the skin signs as the animal became adult. These two conditions occurring together in this breed are well recognised by some breeders. Successful treatment is not possible, although some improvement, particularly of the keratoconjunctivitis sicca, can be obtained. The probable hereditary nature of the condition is an important factor for control.

Ichthyosis in animals resembles but is not identical to ichthyosis in humans. Humans are affected by over a dozen ichthyosiform dermatoses. most are inherited disorders with the onset of signs at or near birth, but some appear in childhood or adulthood. By contrast, all affected dogs are abnormal at birth, with skin cracks and peels off at about 2 weeks of age. Much of the body of these dogs is covered with tightly adhering, tannish gray scales and feathered keratinous projections which give a rough texture to the skin. Although some of these projections adhere to the skin, others constantly flake off, riding up hair shafts in large sheets. Large quantities of scaly debris accumulate on the skin surface forming dry , reddened patches. Masses of hard keratin accumulate on the paws making the entire paw of some dogs appear greatly enlarged, and the whole foot can seem heavier than normal. some dogs may have a severe hair loss.

Ichthyosis in Norfolk Terriers

In Norfolk terrier dogs pedigree analysis has proved an autosomal recessive mode of inheritance. The affected dogs usually have hyperpigmented skin with scaling following mild trauma. The lesions are most prominent in the areas where the skin is not protected by hair and is subject to frequent trauma. Images: Canine ichthyosis in Yellow Labrador retriever, Norfolk terrier, and Australian terrier.