Ichthyosis (Canine Ichthyosiform Dermatosis) is a group of skin disorders characterized by dryness, roughness, and scaliness. Most are genetic, but some are acquired, developing in association with other systemic disease or genetic syndromes. In dogs, this hereditary condition affects the eyes and skin. The eye signs are due to keratoconjunctivitis sicca. The skin signs are of an ichthyosiform dermatosis. This condition occurs in a number of breeds, including the Doberman Pinscher, Rottweiler, Irish Setters, Collie, English Springer Spaniel, Cavalier King Charles Spaniel, Golden Retriever, Labrador Retriever, American Bulldog, West Highland White Terrier, Norfolk Terrier, and Jack Russell Terrier. The owner should understand the chronic nature, incurability, and difficult treatment of ichthyosis. Although the affected dog's general health may seem good, the skin changes are often irreversible.
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 problems 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.
In the Cavalier King charles spaniel, the coat abnormality may be noted at birth as a 'curly coat', with deterioration of the skin with time. These two conditions occurring together in this breed are well recognised. Successful treatment is not possible, although some improvement, particularly of the keratoconjunctivitis sicca eye disorder, can be obtained. The probable hereditary nature of the condition is an important factor for control. In the Norfolk Terrier pedigree analysis has proved an autosomal recessive mode of inheritance. The affected dogs usually have dark skin with scaling following mild trauma.
West Highland White terriers are believed to be predisposed to canine ichthyosiform dermatosis
- Congenital keratoconjunctivitis sicca and ichthyosiform dermatosis in the cavalier King Charles spaniel. Barnett KC. In: J Small Anim Pract. 2006 Sep;47(9):524-8.
- The Merck/Merial Manual for Pet Health (Home edition)
- K. F. Barnhart, K. M. Credille, A. Ambrus and R. W. Dunstan. A Heritable Keratinization Defect of the Superficial Epidermis in Norfolk Terriers.
- Thelma Lee Gross. Veterinary Dermatopathology.
- George H. Muller, Danny W. Scott, Robert Warren Kirk, William H. Miller, Craig E. Griffin. Muller and Kirk's Small Animal Dermatology.