Keratinization disorders in the dog -: A clinical update

Keratinization disorders are very much at the forefront in canine dermatology, because of their frequency, their aetiological and clinical varieties, and for some practitioners, because of the therapeutic difficulties involved. The term of seborrhoea has long been used to designate these disorders, but this term is inexact, since, in addition to the quantitative and qualitative abnormalities in sebaceous secretion, keratinocyte differentiation disorders are also to be observed. The tendency today is to refer to keratinization disorders when speaking of those disorders that cover primary causes, that is to say genetically demonstrated keratinization abnormalities or ones highly suspected as such, because of the strong breed predisposition to some of them. These abnormalities relate to alterations in the keratinocyte function and/or in the sebaceous glands and/or in the surface lipid film. In certain instances, the apparent keratinization abnormality is of unknown origin. The purpose of this update is to present the major characteristics of these keratinization disorders: ichthyosis, primary seborrhoea, vitamin A-responsive dermatosis, zinc-responsive dermatosis, lethal acrodermatitis in the Bull-Terrier, granulomatous sebaceous adenitis, Schnauzer Comedo Syndrome, nasal plantar hyperkeratosis, nasal parakeratosis in the Labrador Retriever, follicular parakeratosis in the Rottweiler, psoriasiform-lichenoid dermatitis, idiopathic lichenoid dermatitis and canine ear margin dermatosis.