Interferon-induced sarcoidosis.

Interferons (IFNs) are widely used for the treatment of various medical diseases. They have marked immunomodulatory effects, and many reports have been published associating IFN therapy with the induction of autoimmune phenomena and other disorders of immune regulation such as sarcoidosis. The clinical presentation of IFN-induced sarcoidosis (IIS) is insidious and can be confused with common constitutional side effects of these drugs. The age of onset of IIS is later than that of naturally occurring sarcoidosis. The most common organs involved are the lungs and skin. In the majority of cases, IIS follows a benign course. As we show in an illustrative case report, complete resolution after discontinuation of IFN therapy can be expected. This review summarises 65 cases of IIS reported in the literature and highlights the pathophysiology, clinical features, diagnostic modalities and therapeutic options for this increasingly recognised phenomenon.