Diagnosis of canine claw disease – a prospective study of 24 dogs

Abstract

The aetiology of claw disease in 24 dogs exhibiting only claw disease was investigated with cytologic examination of claw exudate, complete blood count (CBC), serum biochemistry panel, urinalysis, total thyroxine (tT4) concentration, antinuclear antibody (ANA) titre, bacterial culture and sensitivity testing, fungal culture, histopathology of claw biopsy samples and elimination diet. Abnormalities on the CBC, serum biochemistry panel and urinalysis were minor and nonspeci®c. Total T4 concentrations were within the normal laboratory reference range. Fungal cultures and ANA titres were negative in all dogs. A bacterial infection was present in approximately half of the dogs. On histological examination of claw tissue, a cell-poor or cell-rich interface onychitis was seen in all but one dog. Evidence for an adverse reaction to food was present in four dogs. One dog responded completely to antibiotic therapy. Interface onychitis seems to be a histological reaction pattern of the claw matrix in the dog with various possible underlying aetiologies. In dogs with claw disease as the only clinical sign, the recommended initial diagnostic evaluation includes cytologic examination, bacterial culture and sensitivity, claw biopsy and an elimination diet.

Immunohistochemical Evaluation of Mononuclear Infiltrates in Canine Lupoid Onychodystrophy

“…3,5,[25][26][27]33,34 A syndrome first described by Scott et al 34 and named lupoid onychodystrophy by these authors showed histopathologic changes compatible with lupus erythematosus. However, in a subsequent prospective study of this syndrome, 25 no other systemic or cutaneous features of canine lupus erythematosus could be identified.…”

“…3,5,[25][26][27]33,34 A syndrome first described by Scott et al 34 and named lupoid onychodystrophy by these authors showed histopathologic changes compatible with lupus erythematosus. However, in a subsequent prospective study of this syndrome, 25 no other systemic or cutaneous features of canine lupus erythematosus could be identified. Furthermore, in that study, dogs with claw disease due to pyoderma and food adverse reaction showed the same histopathologic features described by Scott et al 34 These features included interface dermatitis, lymphocytic exocytosis, and hydropic degeneration of the basal cell layer, and the authors suggested that the observed interface dermatitis may be a reaction pattern of the canine claw matrix rather than being diagnostic for a particular etiology.…”

“…12,23,30 In the last decade, a number of studies have been published evaluating claw disease in the dog. 3,5,15,[25][26][27]33,34,36 These studies attempted to define claw disease and possible etiologies in more detail and gave useful information. One of these studies reported a number of dogs with exclusive claw disease, where the only histopathologic findings documented were a bandlike mononuclear infiltrate with interface dermatitis changes, 34 including basal cell hydropic degeneration, degeneration or necrosis of individual keratinocytes in the basal cell layer, and pigmentary incontinence.…”

“…34 No other signs of systemic lupus erythematosus, such as elevated antinuclear antibody titers, anemia, thrombocytopenia, or evidence of glomerulonephritis based on urinalysis and biochemistry panels, were present in dogs with lupoid onychodystrophy in a subsequent prospective study. 25 Furthermore, some dogs with these histopathologic features were diagnosed with bacterial infection or food adverse reaction, indicating that the presence of bandlike mononuclear infiltrates and interface dermatitis may be a ''reaction pattern'' of the canine claw. Vacuolization of claw matrix keratinocytes has been documented in normal canine claws, 27 complicating the interpretation of the histopathologic findings further.…”

Pathology in Practice

“…[1][2][3] Other diseases may involve the claw bed. [1][2][3] Other diseases may involve the claw bed.…”