Vet360 Vol 3 Issue 04 August 2016 - Page 35

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. 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. 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. 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. 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. 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. [\][ۈ[X[[›وHYX^H[\XYۛ\وH[HYX[YHHXX]\HوH\X\KXYXXYۛX\[YHH[[XX\[XH\ SH\ H[[Y\܈\]H[[[][]KH\X]Y][[][\\]HY\وY\ۙH]܈]]^][[H܈XYK\YH UQT M BU ͌UQT Mܚ[˚[ B M ̍H LN B