Erythema Induratum
of Bazin Nodular
Vasculitis
Currently, the terms erythema induratum of Bazin and nodular vasculitis are used as synonyms by most authors to describe the most common form of lobular panniculitis with vasculitis. Some investigators, however, prefer to retain the name erythema induratum of Bazin for those cases in which an etiologic relationship with tuberculosis is demonstrated and refer to the remainder of cases as nodular vasculitis. In some geographic areas, but not in others, polymerase chain reaction investigations have demonstrated that Mycobacterium tuberculosis DNA is present in most of the cutaneous biopsy specimens of patients with erythema induratum of Bazin, supporting the notion that tuberculosis is the most important etiologic factor for this panniculitis.
Erythema induratum of Bazin/nodular vasculitis (EIB/NV) is more frequent in middle-aged women, who develop erythematous subcutaneous nodules and plaques on the posterior aspects of the lower legs. Often, the involved extremities also show erythrocyanosis, heavy column-like calves, erythema surrounding follicular pores, and cutis marmorata . Usually, subcutaneous nodules become adherent to the skin surface, ulcerate , and then heal with scarring. The process is more frequent in obese women with some degree of venous insufficiency of the lower extremities, and the cutaneous lesions develop mostly during the cold months of the winter. Lesions are usually tender but may be indolent or painful under pressure. The course is protracted, and recurrent episodes over years, even decades, are common.
ERYTHEMA INDURATUM OF
BAZIN/NODULAR VASCULITIS AT
AGLANCE
Clinical
- Erythematous subcutaneous nodules and plaques on the posterior aspects of the lower legs
- More frequent in middle-aged women
- Often, ulceration and scarring
- Chronic course
Histopathology
- Mostly lobular panniculitis with vasculitis
- Extensive necrosis of the adipocytes in the center of the fat lobule
- Variable inflammatory infiltrate in the fat lobule: Neutrophils in early lesions and epithelioid histiocytes and multinucleated giant cells in fully developed lesions
- Vasculitis of the small veins and venules of the fat lobule
Treatment
- With positive Mantoux test or when Mycobacterium tuberculosis DNA is demonstrated: A full course of antituberculosis triple-agent therapy
- In other cases: Potassium iodide, supporting bandages, bed rest, and nonsteroidal anti-inflammatory drugs
As in other types of panniculitis, the histopathologic findings in lesions of EIB/NV vary with the evolution of the lesions.139 In early lesions, the fat lobules are scattered by discrete collections of inflammatory cells, mostly neutrophils, and there is extensive necrosis of the adipocytes in the center of the fat lobule. In fully developed lesions, epithelioid histiocytes and multinucleated giant cells occur that ingest lipid from necrotic adipocytes, giving a granulomatous appearance to the infiltrate. Small areas of caseating necrosis are seen at the center of some granulomas, showing all the histopathologic attributes of tuberculosis. Caseating necrosis may extend to the overlying dermis and epidermis, resulting in ulceration and discharge of liquefied necrotic fat.
The histopathologic requirement for vasculitis to establish the diagnosis of erythema induratum of Bazin is controversial. Even accepting vasculitis as a histopathologic criterion, there is no agreement about the nature of the involved vessel; some authors believe that the involved vessel is an artery, others favor venous involvement, and still others consider that both arteries and veins are involved. In our experience, when vasculitis is present, the small veins and venules of the fat lobule are the most commonly involved vessels in lesions of EIB/NV. However, we have studied cases with all the stereotypical clinico-pathologic features of this condition in which serial sections do not demonstrate findings of vasculitis. Therefore, we do not consider vasculitis as a sine qua non criterion to establish the diagnosis erythema induratum of Bazin when other characteristic findings are present, and the name erythema induratum of Bazin is, to us, more appropriate than nodular vasculitis.
In those patients with a strongly positive Mantoux test reaction or when M. tuberculosis DNA is demonstrated in the cutaneous biopsy specimen by polymerase chain reaction techniques, a full course of 9 months of antituberculosis triple-agent therapy is recommended. Potassium iodide is also an effective and rapid treatment for erythema induratum of Bazin. Additional helpful measures include supporting stockings, bed rest, treatment of the venous insufficiency of the lower extremities, and orally administered nonsteroidal antiinflammatory drugs.