[Bazin's erythema induratum: obsolete concept and terminology].

In 1855 Ernest Bazin, who had noted hard, deep and violaceous nodules on the legs of young women, created his famous "erythema induratum" classified among the "erythematous benign scrofulides". Some forty years later, identical lesions were observed associated with tuberculosis; Colcott-Fox called them "érythème induré de Bazin", and ever since that time erythema induratum has been presumed to be of tuberculous origin. In 1900, Darier spoke of "tuberculids" for erythema induratum, and Bazin's "scrofulides" were abusively translated as "tuberculids". In the early 20th century many authors described such skin lesions without any evidence of tuberculosis and later on many papers tried to deny this "systematic" association, but the idea that erythema induratum is caused by tuberculosis still lingers on in 1990. There are many arguments against a tuberculous aetiology, but although very few cases in large series are really associated with tuberculosis many patients have been treated with specific antituberculous agents. For numerous authors, erythema induratum in "tuberculous by definition". In 1945 Montgomery et al. created the "nodular vasculitis" concept. The clinical features are very similar to those of erythema induratum but the disease is certainly not of tuberculous origin. This new pathology has been well developed by French and Spanish authors (Bureau, Duperrat, Vilanova). Despite repeated efforts to separate these two "entities" no clinical or histological data are available to distinguish between erythema induratum and nodular vasculitis. The real meaning of "erythema induratum" is far from being clear: in old publications and sometimes in recent textbooks one can find the same name followed by of Bazin, Whitfield or Hutchinson. Some authors call the disease tuberculids, and other believe it is a true cutaneous tuberculosis.(ABSTRACT TRUNCATED AT 250 WORDS)