One such antigen is the tubercle bacillus. T lymphocyte response to purified protein derivative of tuberculin, which can cause a delayed-type hypersensitivity reaction. To date, no fatal cases of erythema induratum have been reported. The chronic, recurrent, painful nodules and resultant scarring, however, can be a source of significant morbidity. There is a female predominance.
Pulmonary tuberculosis is most common.
Tuberculous cervical lymphadenitis is the next most common finding. Tender, erythematous nodules on lower legs. A chronic, recurrent course. Heals with ulcerations or depressed scars. Involves not only shins, but also calves.