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|14 Dermatological manifestations of systemie diseases

D. Heripret

Dermatological manifestations of systemie diseases are starting to be documented in the cat, although their pathogenesis is not always understood. They are very diverse, clinically, and relate to various systemie illnesses. Their diagnosis is important as these skin lesions enter into the differential diagnosis of many different conditions and may appear before the underlying illness. Unlike in the dog, endocrinopathies very rarely cause skin lesions in the cat. Spontaneous and iatrogenic Cushing’s syndrome are very rare, spontaneous hypothyroidism is exceptionally rare, hyperthyroidism produces a few non-specific changes in the skin, and dermatological signs associated with sex hormone imbalances are now hotly disputed. However, the cat has a whole rangę of systemie disease-associated dermatological lesions, of its own.

■    15 Skin tumours

Franęoise Delisle - Patrick Devauchelle

Tumours of the skin and its adnexae are some of the most diverse and common tumours seen in the cat. Such a large variety is possible because the skin is madę up of lots of different components, each of which can potentially form a tumour. We, therefore, see epithelial tumours which involve the malpighian layer, the adnexal sebaceous or sweat glands and hair follicles, tumours of the melanogenesis system, mesenchymal tumours developing in the dermis or subcutaneous connective tissue, tumours derived from lymphoid tissue and finally, nerve and vascular tumours. The majority of skin tumours in the cat are primary. Tumours secondary to, for example, a pulmonary adenocarcinoma (which is usually asymptomatic) or a mammary adenocarcinoma are much less frequent.

| 16 Genodermatoses

Erie Guaguere - Zeineb Alhaidari - Jacąues Fcmtaine

Genodermatoses are rare, although they constitute a developing field in feline dermatology. In recent years, investigative procedures such as electron microscopy and immunohistochemistry have led to the identification of new genodermatoses. It is important to be familiar with these conditions as they enter into the differential diagnosis of many different dermatoses. Genodermatoses affect the epidermis and its adnexae, the melanogenesis system, the dermo-epidermal junction and the dermis. In this chapter, the following conditions are reviewed: hereditary greasy seborrhoea of the Persian, congenital hypotrichosis, follicular dysplasia, hair dysplasia, pili torti, genetic abnormalities of melanin pigmentation, hereditary cutaneous asthenia, and urticaria pigmentosa of the Sphinx.

■    17 Skin conditions associated with behavioural disorders

Catherine Mege

Skin conditions associated with behavioural disorders are probably rare but remain under-diagnosed in the cat. They are characterised by self-induced lesions (e.g. alopecia, nail chewing and various mutilations). Advances in the study of animal behaviour have enabled these conditions to be placed in the context of behavioural disorders (e.g. anxiety, depression and dysthymia). Thanks to a better understanding of the behaviour of the domestic cat and the availability of new psychotropic drugs, pheromones and behavioural therapies, specific diagnosis and effective treatment are now possible.