DERMATOLOGY
FOOT PAD HYPERKERATOSIS : Familial foot pad hyperkeratosis : Familial foot pad hyperkeratosis has been described in Irish setters , Kerry blue terriers and Labrador and Golden retrievers . Other breeds may be affected as well . Symptoms are usually present by 6 months of age . All foot pads are usually affected with crusting , fissures and pronounced compact keratin that in some cases can produce horns . These lesions can result in severe lameness and pain . Histopathology shows moderate to severe hyperplasia with marked papillated and diffuse hyperkeratosis . Treatment is discussed below . Affected dogs should not be bred .
Idiopathic nasodigital hyperkeratosis : This is an idiopathic hyperkeratosis characterised by hyperkeratosis of the foot pads with or without involvement of the nasal planum . Idiopathic nasodigital hyperkeratosis is seen in older dogs and characterised by increased horny tissue on the nose and / or foot pads . The nose / foot pads appear vegetative with projections of firm , feathered and cracked horny tissue on the nose and / or foot pads . Sometimes only the margins are affected but in severe cases the entire nose and / or foot pad is involved . Certain breeds , such as the Cocker spaniel , may be predisposed . Histologically , idiopathic nasodigital hyperkeratosis is characterized by epidermal hyperplasia and marked orthokeratotic to parakeratotic hyperkeratosis .
The diagnosis is generally based on history and clinical findings , and , in some cases , histopathology . There is no specific treatment for these conditions . Symptomatic treatment may be considered when the hyperkeratosis is a problem . Excess keratin may be removed with regular filing , scissors or a blade and fast growing nails should be trimmed regularly . Daily foot soaks in 50 % propylene glycol may be of benefit . A topical corticosteroid-antibiotic cream may be used for fissured lesions . Owners should be warned of the potential “ mess factor ” associated with these topical therapies . Secondary bacterial infections should be treated where present . Oral Vitamin A therapy may be of benefit . Idiopathic nasodigital hyperkeratosis of the footpads ( http :// foothillsanimalhospital . blogspot .
CUTANEOUS VASCULITIS : Cutaneous vasculitis involves inflammation of the blood vessel walls and perivascular connective tissue , followed by ischaemia and necrosis . This condition may be primary but is usually secondary to infections ( bacteria , rickettsia , fungi ), auto-immune disorders ( e . g . SLE ), chronic diseases ( neoplasia , diabetes mellitus ) and hypersensitivity disorders . Over 50 % of vasculitis cases are idiopathic . With acute vasculitis the face ( nose , lips ), ear pinnae , digits , foot pads , scrotum and oral mucosa are mainly affected . Skin lesions initially include ecchymotic plaques and haemorrhagic pustules . With time fissures and “ punched out ” ulcers appear .
These necrotic lesions are painful . Systemic signs such as fever , anorexia , muscle and joint pain and lymphadenopathy are common . Chronic vasculitis typically affects the ear pinnae , tail tip , digits and foot pads where progressive ischaemia results in well circumscribed lesions . Systemic signs are uncommon in chronic vasculitis cases . The diagnosis is supported by histopathology of skin biopsies of the margins of lesions . Although many cases of vasculitis are idiopathic , attempts should be made to identify an underlying cause .
Treatment for idiopathic vasculitis often includes pentoxifylline as a first choice . Other therapies include prednisolone alone or in combination with azathioprine , chlorambucil or cyclosporine . Tetracycline / niacinamide may be used for milder forms . Topical corticosteroids and 0.1 % tacrolimus may be useful for localized lesions .
CANINE DISTEMPER : Canine distemper is a multisystemic , often fatal disease , caused by a paramyxovirus virus . It commonly causes gastrointestinal , respiratory and neurological disease , but can also cause vesiculopustular dermatitis and foot pad hyperkeratosis (“ hard pad ” disease ). Classic skin signs such as hyperkeratosis of the foot pads often develop after clinical cure or when the earlier clinical manifestations have cleared .
The foot pad lesions may sometimes be seen in older dogs with an incomplete vaccination history . Since vaccination can prevent distemper , distemper related skin disorders are rare . Diagnosis can be confirmed by histopathology when intra-cytoplasmic and intranuclear inclusion bodies can be seen . There is no specific treatment .
SYSTEMIC LUPUS ERYTHEMATOSUS ( SLE ): SLE is an auto-immune condition where multiple circulating auto-antibodies participate in immune-mediated tissue injury directed against the dog ’ s own body . The most common clinical findings include cyclical fever , polyarthritis , kidney disease and skin disease . Skin lesions are diverse and include erythema , ulcers and crusts of the face ( nose , lips ), ear pinnae , limbs , axillae and inguinal area . Ulceration and thickening of the foot pads may also occur .
Diagnosis of SLE can be difficult due to the cyclic nature of the disease . Specific diagnostic tests include the antinuclear antibody test ( ANA test ) and biopsies for histopathology and immunopathology . SLE is treated with immunosuppressive dosages of prednisolone with or without azathioprine or cyclophosamide .
Issue 04 | AUGUST 2016 | 35