Dyschezia in dogs with discrete erosive anal disease and histological lesions suggestive of mucocutaneous lupus erythematosus.

Eight dogs suffered chronic defecation problems characterised by severe dyschezia, manifested by signs of fear and vocalisation on defecation. One or more depigmented, discrete erosions, easily bleeding on palpation, were found in the perineal region. Histopathological changes included interface dermatitis, apoptotic keratinocytes, focal hydropic degeneration of basal epidermal cells, focal thickening of the basement membrane zone and dermal lichenoid infiltrations with mononuclear and plasma cells. A diagnosis of cutaneous or discoid lupus erythematosus was made on the basis of these clinical, physical and specific histopathological changes. The dogs were treated systemically with immunomodulating drugs and good results were obtained.