Since it has been understood that erythema nodosum is not a skin disease, there have been two conflicting opinions as to its nature. One is that it is an independent, acute infectious disease, possibly related to rheumatic fever. According to the other, it may be tuberculous. Uffelmann, of Germany, and Poncet and other French investigators were the first to suggest that certain cases of erythema nodosum were probably related to tuberculosis, because they had observed tuberculous manifestations in conjunction with the disease.
Pollak,1 of Austria, arrived at a similar, though more general, theory by another road. This was after the Pirquet tuberculin test had come into use. On performing the Pirquet test on a number of outpatients (children) with erythema nodosum, he found that they all had positive reactions, even between the ages of 2 and 6 years, when positive tuberculin reactions are not very common. For this reason,