By Gary M. White, MD
Nodular vasculitis (NV) and erythema induratum (EI) are both terms that have been used to describe an inflammatory panniculitis and vasculitis of the calves. There is some confusion of the nomenclature. Classically, the term NV has been used to describe cases lacking evidence of infection by tuberculosis whereas EI has been used when tuberculosis infection is found. Alternatively, some use NV and EI interchangeably and use the term erythema induratum of Bazin (Bazin's disease) to refer to those cases caused by infection from Mycobacterium tuberculosis.
When an infectious agent is found, it is most commonly M. tuberculosis. However M. avium, Nocardia, Pseudomonas, and Fusarium have been associated with EI.
Tender, red, deep-seated nodules mainly on the calves but also elsewhere on the legs is characteristic. Ulceration frequently occurs.
A biopsy deep enough to obtain subcutaneous fat is in order. Mycobacterium tuberculosis may or may not be demonstrated with a Ziehl-Neelsen (ZN) stain or culture. A PPD should be obtained. The final diagnosis may often be obtained by polymerase chain reaction (PCR) detection of mycobacterial DNA in a skin biopsy. In one study of 26 cases of erythema induratum, PCR was positive in 54% and correlated with a documented response to antituberculous treatment in 80%. In another study, PCR was positive in 77%.
Workup for tuberculosis should be done by an infectious disease specialist. Effective therapy with antituberculous drugs clears the skin. If antituberculous therapy does not clear the skin, supersaturated potassium iodine and prednisone have been used.
Homepage | FAQs | Use of Images | Contact Dr. White