Pathology of an ulcerative dermatitis in Belgian Landrace sows

Chronic ulcers of the skin were observed in three Belgian Landrace sows. Lesions were located on ears, limbs, and in the mammary region and were resistant to treatment that included corticosteroid therapy. Major histologic changes were located at the dermo-epidermal junction. Ulcers were deep, and the adjacent epidermis had marked hyperkeratosis, acanthosis, and intracellular edema. Dermatitis was prominent, essentially located in the superficial dermis. By electron microscopy, basal lamina appeared disrupted. Dermo-epidermal separation occurred beneath the basal lamina. Collagen was morphologically normal. Desmosomes, hemidesmosomes, and anchorage fibers were present in areas adjacent to lesions. Ulcerative dermatitis of sows is morphologically similar to pemphigus, pemphigoid, systemic lupus erythematosus, epidermolysis bullosa simplex, erythema multiforme, toxic epidermal necrolysis, and drug eruption. However, significant differences exist between ulcerative dermatitis and these conditions.