Among autoimmune skin diseases, pemphigus foliaceous (PF), discoid lupus erythematosus (DLE) and pemphigus erythematosus (PE) are more frequently encountered in dogs. PE shares both clinical and histological findings with PF and DLE. Clinical lesions appear on the muzzle, periocular areas and dorsal portion of the nose, ears and feet. Intra-epithelial pustules with acantholytic cells (typical in PF) and interface dermatitis with hydropic degeneration and apoptosis of basal keratinocytes (typical in DLE) are visible.
Since the age of 4 months, a 7 years-old female Newfoundland dog showed a skin disease that began with crusts on the muzzle and on the nasal and periocular areas, subsequently affecting the limbs. The owners stated that the antibiotic therapy was completely ineffective while prednisolone administration (2 mg/Kg BID) evolved in considerable enhancement. Dose reduction to 1 mg/Kg BID always determined recrudescence and lesion worsening. The general conditions of the dog were good at clinical examination. The dermatological examination showed depigmentation of the muzzle and of the dorsal portion of the nose; a pustulous dermatitis, small areas of erosions and alopecia (fig. 1) were detected. Analogous less severe lesions were observed on both periocular areas and particularly on the upper eyelids (fig. 2). Finally the limbs show a dermatitis with severe pustules, ulcers, corneal scales and alopecia (Fig.3).
The cytological examination of the crusts showed the presence of some neutrophils with intra-cellular cocci and a few acantholytic cells. Since the cortisone therapy had already been suspended for 20 days, skin biopsy samples were collected from limbs and nose. The histopathological examination showed epidermal hyperplasia with orthokeratotic keratosis and several small intraepidermal-subcorneal pustules with neutrophils and a few acantholytic cells. Interface dermatitis was observable in both biopsies and was characterized by lymphocyte infiltrate, plasma cells and melanophages; hydropic degeneration and apoptosis of basal keratinocytes was observed. Taken together the reported findings are compatible with pemphigus erythematosus.
Some authors consider the PE as a localized photo-sensible form of PF. However in the dog an interface dermatitis, resembling what observed in LED, is present. Recently this flogistic process has been considered as an non-specific response shared by several nasal dermatosis. Some authors however reported cases in which ANA were detected in the serum together with intercellular deposition of Ig (between keratinocytes and in the BMZ).
cane e del gatto. Ed. italiana a cura di A. Fondati, ed. UTET, Torino, p 114. – Scott D. W., Miller W.H., Griffin C.E. Muller & Kirk’s Small Animal Dermatology, 6th Ed WB Saunders Co, Philadelphia, 2001.