Erythema induratum can be a manifestation of:
Erythema induratum of Bazin/ Nodular tuberculid /Bazin disease - Erythematous nodules develop over posterior leg, usually ulcerates - Lobular panniculitis Erythema nodosum/ Facultative tuberculid -develop over anterior leg, which does not ulcerate ( differentiating point with Erythema induratum)
Lepra reaction
Tuberculosis
Dermatitis
Psoriasis
Mycobacterial Infections