A 29-year-old woman presented with a two years history for asymptomatic purple to brown lesions on her nose, cheeks and frontal areas. No pruritus or scaliness was present. The patient had no rash in any other location and no history of recent drug use. Routine laboratory tests were normal...

 What is your diagnosis?

Diagnosis: Sarcoidosis

Sarcoidosis is a systemic granulomatous disease of uncertain etiology.

There are severeal distinct appearances to cutaneous sarcoidosis. Lupus pernio characterized by persistent, pulrple plaques on the nose and is strongly associated with nasal mucosal lesions, and with lung and bone involvement.

Histopathologically, in typical lesions of cutaneous sarcoidosis, there are well-demarcated islands of epithelioid cells containing only few, if any, giant cells.

For unknown reasons, it seems that sarcoidosis is a common disease in northern Iran.