There are many etiologies. Idiopathic nodular vasculitis may be seen on the calves of women in middle age who have varicosities. Mycobacterium tuberculosis infection is one of the strongest associated triggers. The term erythema induratum (of Bazin) refers specifically to cases of nodular vasculitis associated with underlying tuberculosis. Cases can also be induced by infectious agents such as Nocardia, Pseudomonas, Chlamydia, or hepatitis B or hepatitis C infections. Drugs may also be causative agents, with tumor necrosis factor (TNF)-alpha inhibitors, notably etanercept, implicated in case reports. The condition is thought to be either an immune complex-mediated vasculitis or a type IV cell-mediated response to an antigenic stimulus.
Related topic: cutaneous tuberculosis
L95.8 – Other vasculitis limited to the skin
55275006 – Nodular vasculitis
- Erythema nodosum is usually found on the anterior lower legs instead of posterior, is more septal, is usually less granulomatous, and is usually without vasculitis.
- Other types of infection-induced panniculitis tend to demonstrate more prominent neutrophils. Organisms may be identified with special stains and cultures.
- Polyarteritis nodosa
- Perniosis, also known as pernio and chilblains, occurs primarily on acral sites, with erythematous or violaceous macules, plaques, nodules, or ulcers, and is associated with cold exposure. Histologically, perivascular and often perieccrine lymphocytes, dermal edema, edema of vessel walls, and sometimes thrombi are seen.