Fatal thrombocytopenic hemorrhagic diathesis associated with dapsone administration to a dog.

Dapsone was given for six days to a dog with chronic skin disease. The dog then became weak and anorectic, and it vomited and had purpura caused by severe thrombocytopenic hemorrhagic diathesis. Despite treatment, the dog died a week later. There were clinical and pathologic evidence that the dog's platelets and megakaryocytes had been destroyed during the first few days of dapsone therapy. It was concluded that the syndrome was dapsone-induced and that thrombocytopenia should be considered among the adverse reactions to dapsone in the dog.