Mycobacterial dermatitis.

Mycobacterial skin disease in cats associated with atypical mycobacteria is an uncommon disease in small animal practice, and the disease is rarely encountered in dogs. A mycobacterial etiology should be considered in cases of chronic nodular dermatitis, draining tracts, and panniculitis. Cats and dogs affected with atypical mycobacterial infections are usually otherwise healthy, and systemic illness is unusual. In most cases, a diagnosis is made based on histopathological findings and growth of a causative organism. Group IV atypical mycobacteria can usually be grown following submission of affected tissue. Treatment should be based on antibiotic sensitivity test results. Treatment is prolonged and is unsuccessful in many cases. In cases of feline leprosy and canine leproid granuloma syndrome, organisms are difficult if not impossible to grow, and clinical and histopathological findings should be used to make a diagnosis. Spontaneous resolution of disease has been reported in atypical mycobacteriosis, feline leprosy, and canine leproid granuloma syndrome.