Nocardiosis is an infection by several species of the genus Nocardia (family Actinomycetaceae). Perhaps the most common is Nocardia brasiliensis. Nocardia infection may be either systemic or cutaneous. Cutaneous infection may occur in various forms including lymphocutaneous, cervicofacial (in children), hematogenous spread of systemic disease, mycetoma or superficial skin infection. Nocardia is found in soil and may enter the skin through trauma, e.g an insect bite [Dermatology 1999;198;159].
A lesion may develop at the site of trauma and then spread as nodular lymphagitis. The initial lesion may be an inflammatory nodule, plaque or abscess. Necrosis and/or ulceration may occur. Immunocompromised patients are at increased risk.
The organism may be seen on gram stain as delicate branching gram-positive rods. It may be cultured. Histology may show sulfur granules which represent gram positive rods at the center of the microabscess.
The latest infectious disease treatment guidelines should be consulted.
Dermatology Online Journal 17(12)
Indian Dermatol Online J 2014;5:300
Primary Nocardiosis from N. Brasiliensis at an IV catheter site. JAMA Derm 2015;151;895