Panniculitis with vasculitis.

Panniculitides encompass a great number of different entities; however, once a vasculitis has been detected histopathologically within the subcutaneous tissue, the differential diagnosis is mainly restricted to polyarteritis (panarteritis) nodosa (PAN), nodular vasculitis (NV), and Bazin's erythema induratum (EI). Patients with PAN may have the disease confined to the skin, but must be followed over a long period because many of them develop late systemic disease. The NV/EI group represents by far the most common type of lobular panniculitis with vasculitis; we prefer keeping the distinction between the two entities by underlining the equation NV positive tuberculin skin test = EI. Other lobular panniculitides with vasculitis are exceedingly rare and set in a systemic background which can be infectious (lepromatous leprosy panniculitides) or autoimmune/dysreactive (neutrophilic lobular panniculitis in rheumatoid arthritis, lobular panniculitis in inflammatory bowel disease).

Dapsone dependent nodular panniculitis.

A patient recorded to be suffering from tuberculoid leprosy since 1973 and on regular Dapsone monotherapy for about nine years developed asymmetrical, erythematous, subcutaneous, nodular swellings restricted chiefly to the extensor aspects of lower limbs two months after discontinuation of Dapsone therapy. During the course of Dapsone treatment, the patient had developed similar swellings twice previously each time when he stopped the drug for about a month. The swellings disappeared on commencement of Dapsone Treatment. This has been reconfirmed under our supervision. The biopsy of one of the lesions revealed panniculitis with vasculitis. The original diagnosis of leprosy was probably invalid.