Microscopic polyangiitis secondary to silica exposure.

There is sufficient evidence of the capacity of silica to induce autoimmunity in patients with some type of genetic susceptibility. There are several autoimmune diseases related to this exposure (rheumatoid arthritis, Sjögren's syndrome, sarcoidosis, systemic sclerosis). Nodular silicosis (clinical expression of this exposure in lungs) generates apoptosis, inflammation, loss of tolerance and a respiratory burst. There is evidence that relates silica with induction of antineutrophil cytoplasmic antibodies, but, until it is better explained, the reports of systemic vasculitis secondary to silica exposure are inconclusive. We describe a case of a patient with a history of occupational exposure to silica who developed microscopic polyangiitis.