Sarcoidosis at onset of Psoriasis: a common immunopathogenesis. Review and case report.

Sarcoidosis is an inflammatory systemic disease that may present in many different ways. The pathophysiological mechanisms are not still well known, although sarcoidosis results from an exaggerated Th1 immune response. About 30% of sarcoidosis patients may suffer from skin lesions during the course of the disease and, occasionally, psoriasiform lesions have been observed. Sarcoidosis may present associated with other diseases and psoriasis is actually one of them, even though not particularly frequent. Few cases of patients who showed clinical and histological features compatible with both pulmonary sarcoidosis and psoriasis vulgaris have been reported. We report an interesting case of a patient affected by sarcoidosis at the onset of psoriasis and discuss immunopathogenetic mechanisms that can be associated with these conditions. Recent data confirm that sarcoidosis is a Th1/Th17 multisystem disorder. These clarifications may be helpful in the management of the diseases and in identifying patients at risk.