Semin Respir Crit Care Med. 2020 Jun 27. doi: 10.1055/s-0040-1713130. Online ahead of print.
Sarcoidosis is a chronic, multisystem, inflammatory disorder of unknown etiology that is characterized by noncaseating granulomas that impair normal organ functioning. Sarcoidosis predominantly affects the lungs, but the skin is often cited as the second most frequently involved organ. Cutaneous manifestations of sarcoidosis are highly variable and ongoing research seeks to better understand the relationship between clinical morphology and disease prognosis. Skin findings in patients with sarcoidosis can be "specific," in which sarcoidal granulomas infiltrate the skin, or they can represent a "nonspecific" reactive inflammatory process, as is seen in calcinosis cutis and erythema nodosum. Cutaneous sarcoidosis can be the initial presenting sign or develop later in the course of the disease. In some patients, the skin will be the most involved and impactful organ system and will drive therapy. In other cases, the skin will be an incidental or minor finding, but may be easily accessible for biopsy to confirm the diagnosis. There are many potential therapies for sarcoidosis, though no one therapy is universally effective.