242 (23)

24

Table 24 :1: Aetiology of pododermatoses

History

INFECTIOUS DERMATOSES

Powirus infection Herpesvirus infection

Herpesvirus-associated erythema multiforme

Calicivirus infection

Bite abscess

Bacterial paronychia

Leprosy

Atypical mycobacterial infection

Nocardiosis

Actinomycosis

Botryomycosis

FUNGAL DERMATOSES

Dermatophytosis

Malassezia demnatitis

Candidiasis

Subcutaneous mycoses

Sporotrichosis

Cryptococcosis

Histoplasmosis

Blastomycosis

Coccidioidomycosis

PARASITIC DERMATOSES

Trombiculiasis Demodicosis Notoedric mange Anatrichosomiasis Leishmaniasis

ALLERGIC DERMATOSES

Atopic dermatitis Food intolerance Mosąuito bite hypersensitivity Allergic contact dermatitis

EOSINOPHILIC GRANULOMA COMPLEX

Eosinophilic plaąues Eosinophilic granuloma

AUTO-IMMUNE DERMATOSES

Pemphigus foliaceus Discoid lupus erythematosus Systemie lupus erythematosus

OTHER IMMUNE MEDIATED DERMATOSES

Cutaneous drug reactions Plasma celi pododermatitis

HEREDITARY DERMATOSES

Congenital hypotrichosis Pili torti

Hereditary epidermolysis bullosa Yitiligo

ENVIRONMENTAL DERMATOSES

Burns

Frostbite

Irritant contact dermatitis

TUMOURS

Sąuamous celi carcinoma

Trichofolliculoma

Fibrosarcoma complex

Cutaneous epitheliotropic T celi lymphoma

Digital metastasis of a pulmonary adenocarcinoma

DERMATOSES ASSOCIATED WITH A SYSTEMIC ILLNESS

Pancreatic paraneoplastic alopecia Paraneoplastic exfoliative dermatitis Superficial necrolytic dermatitis Vasculitis

Degenerative, mucinous lymphocytic mural folliculitis Xanthomatosis

SKIN CONDITIONS ASSOCIATED WITH BEHAVIOURAL DISORDERS

Nail chewing

The history helps to steer the clinician towards particular differentials. It is a vital step in the diagnostic process. Important points to consider are :

Breed: Persians are predisposed to dermatophytosis. In the Birman, claws are absent or rudimentary in congenital hypotrichosis⁵ (Fig. 24 : 2). The Siamese breed is predisposed to vitiligo which will often affect the feet ⁶ (depigmentation of the footpads (Fig. 24 : 3)), and morę rarely junctional epidermolysis bullosa⁷.

Age of onset: development of pedał lesions in a cat under 6 months would suggest dermatophytosis, a parasitic dermatosis (e.g. notoedric mange and demodicosis), a viral dermatosis (e.g. herpesvirus or calicivirus), or a genodermatosis (e.g. junctional⁷ and dystrophic epidermolysis bullosa⁸⁹, congenital hypotrichosis and pili torti). Pedał lesions in a young adult would initially suggest dermatophytosis or an allergic dermatitis (e.g. atopic dermatitis or food intolerance) (Figs 24 : 4-7). In an older, adult animal, auto-immune dermatoses ¹⁴ (e.g. pemphigus foliaceus (Figs 24 : 8,9) or systemie lupus erythematosus (Fig. 24 : 10)), dermatoses associated with systemie disease ¹⁴ (e.g. superficial