In lupus pernio, purple swellings resembling chilblains develop on the ears, nose, or cheeks. However, unlike chilblains, the swellings do not itch or cause pain. Lupus pernio is a characteristic feature of sarcoidosis, a disorder in which areas of inflamed tissue (called granulomas) develop in one or more parts of the body, most often the lungs, lymph nodes, skin, and eyes.
The cause of sarcoidosis is unknown, but it is thought to be an exaggerated response of the immune system, possibly to an infection.
Lupus pernio is usually treated with corticosteroids, which usually improve appearance, although the facial swellings may not disappear completely